Is it possible to obtain an STC for single-pilot ops in a jet certified for two pilots? I have been doing research on whether or not one could realistically obtain an STC for a super-midsize jet certified for two pilots and legally fly it single-pilot.

For reference, my chosen aircraft is the Hawker 4000, which can be had for significantly less than most jets certified from the manufacturer for single-pilot ops. Additionally, the Hawker boasts performance figures that laugh at all other light jet numbers and its Relative Value Analysis (RVA) is comparable to jets costing $25M+.

I cannot find information anywhere on gaining single pilot certification in any aircraft not originally certified for single pilot operations. I would even take into consideration the possibility of a complete retrofit of the flight deck with Garmin 3000 or some other system designed to be flown single pilot (like that in the Phenom 300).

Thanks!

Cessna did this sort of thing for the CE-525 series (CJ) jets. Effectively the required crew varies based on cockpit arrangement/equipment. As per the type cert

  Minimum Crew for all Flights (see NOTE 5 for cockpit equipment/arrangement restrictions):

  One pilot (in the left  for all Flights pilot seat) plus additional
  equipment as specified in the Kinds of Operations Equipment List
  (KOEL) contained in the Limitations Section of the FAA Approved
  Airplane Flight Manual (AFM)

  OR

  One pilot and one copilot

Note 5 for reference:

  Approval for operation with a minimum crew of one pilot is based upon
  the cockpit equipment installation and arrangement evaluated during
  FAA certification testing. No significant changes may be made to the
  installed cockpit equipment or arrangement (EFIS, autopilot, avionics,
  etc.), except as permitted by the approved MMEL, without prior
  approval from the responsible Aircraft Certification Office.

However that is the original type cert and it was done by the manufacturer, who has the resources to test these kinds of things. Doing it on your own is bound to be cost prohibitive, even considering you may have to pay a second pilot to fly with you for the entire ownership of the aircraft.

This is also fairly similar to the case in the heavy metal world with the dropping of flight engineers and navigators when control was consolidated to the two pilots. So far as I know none of this was done via STC but appeared on the TC itself.

Technically it may be possible, practically, it seems unlikely.

If your looking for single pilot jet performance there are plenty of early era ex-military jets hitting the market that are far faster than any business jet you can buy...


May pilots perform FMS database updates under Part 135? Are pilots allowed to perform FMS database updates under part 135?  If so, do they need formal training entered in their pilot records before they are allowed to do it?

Updating a navigation database used to be considered preventative maintenance and was required to be performed by a mechanic under Part 135.  However, the regulations were changed at the end of 2012 (here is the final rule) and it no longer falls under this category so pilots are allowed to update "aeronautical databases" (a new term) if it is "easy" to do (see the regulation quoted below for the exact requirements).  There is no training requirement specified by the regulations, however there may be company specific procedures which require it.

14 CFR 43.3 was updated, and now says (in part):

  (k) Updates of databases in installed avionics meeting the conditions
  of this paragraph are not considered maintenance and may be performed
  by pilots provided:

  (1) The database upload is:

  (i) Initiated from the flight deck;

  (ii) Performed without disassembling the avionics unit; and

  (iii) Performed without the use of tools and/or special equipment.

  (2) The pilot must comply with the certificate holder's procedures or
  the manufacturer's instructions.

  (3) The holder of operating certificates must make available written
  procedures consistent with manufacturer's instructions to the pilot
  that describe how to:

  (i) Perform the database update; and

  (ii) Determine the status of the data upload.


Can I use PVC pipes for the rib on the wings of my homemade airplane? Can I use a PVC pipe as the rib of the wings of my homemade airplane?A rib is already load tested, and it failed at 40kg of weight and it is supposed to hold just 10kg in flight.

Yes, of course you can.

However, it's probably not a very good idea.

PVC pipes are pretty strong and light; circular-section PVC pipes have an excellent strength-to-weight ratio.

Being strong and light isn't enough though. Construction materials need to have the appropriate properties (like being strong and light) in the right conditions.

In the case of an aeroplane wing, that includes the conditions that aeroplane wings are subjected to: rapidly-changing stresses, vibration, sustained load, torsion and so on. You need to know: will PVC remain strong under such conditions?

Then presumably, you will need to find various ways of joining your PVC sections to each other and to other materials. How will these joins be made? How will they behave under the conditions an aeroplane wing is subjected to? How will the joining methods affect the properties of the PVC pipes?

Aircraft designers tend towards the conservative; even the most radical of aircraft designers would not be considered daring compared to the radical leaps taken by designers in other fields. That's because the chief reward for brave leaps in aviation is death.

All the same, over its history, aviation has tried all kinds of things (usually, quite carefully). If aviation has successfully used PVC pipes in aircraft construction, there'll be a record of it and a tradition of it. The successful pioneers of PVC-pipe-based aviation will not, however, have embarked on their adventures on the basis of an encouraging Stack Exchange reply.

If you don't already know the answers to the questions I mentioned above, and are not already in possession of reliable information about techniques, tools, practices and theory for working safely with PVC load-bearing structures, I'd prefer to use PVC pipes for plumbing only.


What runway alignment should I expect from a straight-in approach? More precisely, in the case when a straight-in approach is present, what is the maximum angle between the final approach course and the runway heading for a straight-in minimum apply?

I had thought it is 15° for GPS IAP and 30° for others. However, when I looked at RNAV (GPS) RWY 28L @ KMRY, the angle is |279.4° - 261°| = 18.4° > 15°. Is there any other rule that applies, or is this simply an exception?

Note that on IAP runway diagram (bottom-left), there is usually an arrow with a distance from FAF to MAP and course direction, and they are omitted here.

This is an interesting question because it turns out that RNAV approach criteria aren't defined in the TERPS as you would expect. Instead, there's a separate FAA order 8260.58 for RNAV approaches.

The TERPS does indeed give 30° as the maximum offset for most approaches (e.g. section 4-2-4) and 15° for VOR/DME RNAV approaches (section 13-3-4), but VOR/DME RNAV approaches are still based on ground stations (section 13-1):

  VOR/DME RNAV systems use signals based solely upon a VOR/DME, VORTAC,
  or TACAN reference facility. These systems use radials and distances
  from a reference facility to compute position and flight track
  information

On the other hand, the criteria for 'true' RNAV approaches not based on ground stations are defined in 8260.58 and they allow for offsets up to 30°  for approaches without vertical guidance (section 3-2-2):

  a. Offset. When the final course must be offset, it may be offset up
  to 30 degrees (published separately from vertically guided) when the
  following conditions are met:

  (1) Offset ≤ 5 degrees. Align the course through LTP.

  (2) Offset > 5 degrees and 10 ≤ degrees. The course must
  cross the runway centerline extended at least 1500 feet prior to LTP
  (5200 feet maximum).

  (3) Offset > 10 degrees and ≤ 20 degrees. The
  course must cross the runway centerline extended at least 3000 feet
  prior to LTP (5200 feet maximum). For offsets > 15 degrees, CAT C/D
  minimum published visibility 1 SM, minimum HAT of 300 feet.

  (4) Offset 20 to 30 degrees (CAT A/B only). The course must cross the runway centerline extended at least 4500 feet prior to the LTP (5200 feet
  maximum).

Since the approach you showed doesn't have vertical guidance, it would fall under this section and therefore the offset of 16.76° marked on the plate is normal.


Vancouver FIR meaning In looking at Garmin Pilot, there is something labeled "Vancouver FIR" which has 3 segments. It's located over the northern Cascades and to the east of the northern tip of Vancouver Island (Canada). What is that "Vancouver FIR"?

Specifically, I'm interested in flying over those mountains at a few thousand feet AGL (in and among the mountains) and am wondering if this "Vancouver FIR" is something I need to worry about.

I'm currently working on obtaining my Private Pilot Certificate in the United States.

FIR stands for Flight Information Region.  There is lots of information about these on-line, to the point that it isn't worth regurgitating it here.

However, the FIR should be the least of your concerns at this stage of your training...

If you want to fly "in and among the mountains" of the extremely rugged North Cascades, I would strongly recommend you get your Private Pilot Certificate first, then take a mountain flying course as a minimum before you get any lower than 1000' above the highest peak in a sector, and/or gliding distance from a wide flat valley floor with suitable emergency landing spots.

Narrow valleys and downdrafts on the lee side of ridges are killers.

I live up here in Washington state and have flown in the mountains for years, but they are no place for a beginner on a student solo.  Especially this time of year.


Changing the interception angle in autopilot for OBS or VOR in the G1000 from 30 to something more aggressive I am flying the G1000 and have noticed that if I program in an OBS TO or a VOR TO (this might apply to FROM as well), the angle at which I fly relative to my programmed in bearing is 30 degrees.

For example, if I am flying 180 and want to fly to an airport nearby with an OBS setting of 250 and put this in and turn on NAV, the plane will turn to 220, which indeed will intercept 250 at some point. But if I am not far from the airport I am wanting to approach at 250, this interception will get me too close to the airport, by the time I reach 250. So I would like a more aggressive interception angle than 30... maybe 90? How would I do that?

The manual does not state any way to do that. You can adjust the vertical navigation flight path angle, but not the horizontal intercept angle. You'll have to fly that yourself. In addition, in this case you should be telling the G1000 where you want it to go, rather than which heading to go. If you just tell it the heading it will never figure out what it has to do to get you to that nearby airport, so in this case it is working as advertised.


In which phases of flight should the carb heat be turned on? I have about 200 flight hours in a fuel-injected C172. I have just jointly bought a C152 with a carburetor and I am getting used to using the carb heat. I am scared whenever I hear stories about engine failures due to carb icing.

What I know is to turn CH on when:

RPM lower than 2000
When visible moisture is in the air and when it's raining

But should I leave CH on when taking off in the rain? Can you give me some ideas about other phases and conditions of the flight when I should turn on the carb heat?

Carburettor icing is rare at high RPMs, as there will not be much of a venturi effect. To have carburettor icing in such a scenario, it would have to be very cold and very humid/wet, in which case you would probably also encounter airframe icing, and might want to reconsider your flight.

Applying carby heat has two downsides:

The air will be unfiltered, meaning dirt or other contaminants can be sucked into the engine;
More importantly, the warm air means you won't be able to reach your usual maximum RPM.

These are two undesirable traits for takeoff.

The POH in a Cessna 172 I fly says to have carburettor heat off for takeoff and landing, but only really says it should be on when you suspect icing. I was taught to be much more conservative - prevention is better than cure. I apply carby heat whenever the RPM is below the 'green range', unless it is especially hot and dry outside. However, I remove it when I'm about 30 seconds from landing, in case I need that extra power for a go-around. You also shouldn't apply it 'half way'. Either it's all in or all out.

Boldmethod has a good article on why it's important, and you should pay attention to the conditions where it is most likely to occur.


Will there be dynamic or variable separation minima in future? In the future, is it possible to apply in the same airspace different separations between pairs of aircraft? Depending on the relative speed, navigation capacity of the aircraft, intersection geometry, etc.

What will be necessary to be able implement this type of separation?

There already is, to some extend.

Firstly, there is a big difference between separation in surveillance environments and non-radar environments. In non-radar environments, the separation minima are much larger, because separation is based on position reports provided by the aircraft, which is deemed less accurate than radar data.

In radar environments, the separation needed is generally 5 NM. However, in many terminal areas this is reduced to 3 NM - but only for aircraft going 250 KIAS or less (so, reduced relative speed). Moreover, on final approach, separation is commonly reduced to 2,5 NM - again, since the planes are going slow and pointing in the same direction (the runway), the relative speed is low.

Note that the navigation capabilities of individual aircraft does not matter, since separation is based on ground based equipment (radar), NOT on position information provided by the aircraft.


What is the fuel burn rate for climb of a C-130J Hercules? I am trying to graph the payload range for a C-130J Hercules and I need an approximate value for fuel burn rate which I cannot seem to find online. Does anyone know approximately how much fuel a C-130J hercules would burn to climb 1000 ft?
This would be under atmospheric conditions and at standard speeds. The fuel burn rate of any other similar aircrafts is also appreciated. I am just looking for an educated estimation.

A rough estimation: for a mass of 60000 kg, the energy needed for that (1000 ft = 305 m) altitude change will be 60000 x 9,8 x 305 = 179 MJ. Jet fuel has a heating value of 44 MJ/kg, and if we assume a global conversion efficiency of –say– 7%, the fuel needed would be 179/(44 x 0,07) = 58 kg...


Will I have to redo flight time for switching to a new CFI? The CFI that I am flying with is experiencing health issues and may not be able to fly anymore.  If I switch to a different instructor will I have to redo flight time with the new instructor or is it perfectly OK to log flight instruction with different instructors.  So far I have only about 4 hours instruction and have not soloed.  My jurisdiction is the USA.

You will not need to repeat the hours. I flew with two different instructors during my training due to my first one heading off to the airlines and it was not an issue, as a matter of fact its pretty common. The FAA considers flight time, flight time. Once you logged the hours they are yours for the rest of your life.

However the new instructor will most likely have you repeat some of the stuff you went over with the first CFI just to see where your skills are at. If you only have 4 hours under your belt is likely you have just done turns, climbs, decents, and possibly stalls so switching instructors will be no issue. It takes a fair bit of time to build a rhythm with an instructor anyway.

Just some advice, if you are at a flight school that has a few others to pick from its worth it to ask them what their intentions are. Most instructors are there to build hours towards ATP then its off to the airlines. You should ask instructors how many hours they have left if they are going to ATP out, the more hours they have the longer they will be around. This will help you prevent the situation where you have to change instructors again.


Why does the BAe 146 have higher maintenance costs than other comparable jet aircraft? In many discussion(1)(2) it is stated that the BAe 146 has higher maintenance cost and higher cost of operations in compare to other jets due to its complexity.

  Quoting IslandHopperCO (Reply 21): The PSA (then USAir) BAe-146s were
  parked in the desert in 1991 due to high maintenance costs according
  to USAir. More likely was that USAir couldn't turn a profit on the
  western routes that PSA used to make money on, because those routes
  were dropped when the plane were parked.

  No that is pretty much correct...PSA also had major problems with
  reliability. In fact BAE provided them with a spare because they broke
  down so much. Who knows if they would have gotten rid of them because
  of that. They were kinda ugly but in a cute way....that smile really
  did it!

Why are the maintenance and operating cost higher?
Why is it more complex than other jets?

higher maintenance cost and higher cost of operations in compare to other jets due to its complexity.

That seems ironic considering what Wikipedia says

According to the BAe 146's chief designer, Bob Grigg, from the very start of the design process, making the aircraft as easy to maintain as possible and keeping operator's running costs as low as possible were considerably high priorities.
Velupillai 1981, pp. 1245-1246, 1253.

Why is it more complex than other jets?

Because it has four engines? I believe short-haul airliners of similar capacity mostly have only two.

Why are the maintenance and operating cost higher?

Wikipedia says of the original Lycoming engines used:

The ALF 502 has experienced multiple issues. Its internal electronics could overheat, triggering an automatic shutdown of an engine with no option of in-flight restart, and certain rare atmospheric conditions could cause a loss of engine thrust due to internal icing.[29] Additionally, the BAe 146 experienced aerotoxic syndrome due to leakage of tricresyl phosphate (TCP) into its bleed air; this has been blamed on problems with leaking engine seals. Exposure to these toxic fumes is a dangerous health risk

Note: the above is speculation, you'd have to ask an airline maintenance manager.
There are interesting maintenance anecdotes / whinges at pprune

High price of spare parts.
Accessibility of some components.
N1 harness that goes through engine fan strut.
Quick release fastners needed on engine core covers.
FADEC harness (RJ) can't be changed without dropping the donk.
Lower engine power cables that freeze full of moisture.
Corrosion issuse with the gear bay longeron strut.
The nose landing gear steering lube leaks out and the internals corrode
Air con pacs are unreliable.
Honeywell apu's are unreliable, Garrets better.
Fuel tanks need proper draining off every day to get rid of moisture.
Tri-wing fasteners often fail on removal.


What is this F-18 Hornet "air intake" for? I think I read once that they served to cool the on-board computer systems, but I'm not sure.

It's for keeping the boundary layer flow from entering the intake, it's called a splitter plate. I think it's done to prevent turbulence inside the turbine (prevent compressor stall) and to make sure the intake doesn't ingest slow air, to maximize efficiency.


What are the bumps in the F-22 Raptor wing for? As you can see in the picture there are several bulges or bumps in the wing that are located in the aileron and flaps. Somebody told me these are to hide the linear actuator, pushrod, and control horn. However, if the bulge is connected to the wing and aileron how is it possible for it to be there? If the aileron is moving independent of the wing, how is the bulge connected to both at the same time?

Yes they are fairings for the actuating mechanism for the control surface.  I can't speak directly to the F-22's details but, this kind of thing is done on lots of airplanes.  The F-22's control surface blister fairings are perhaps a bit more sophisticated and 100 times more expensive, but the concept isn't all that special.
The blister on the fixed structure will have an overlap with the blister on the moving element.  The blister on the moving element, like the aileron in the image below, will slip under the fixed part of the blister when it moves down, and there will be additional material forward of the joint that is exposed when the aileron moves up to maintain the contour.
In the somewhat grainy image, you can make out a dark line along the interface between aileron and wing that follows the profile of the blister (along with staining that could be discoloration from seeping hydraulic fluid).  There is likely a flexible seal strip to provide the smoothest possible transition but with enough compliance to accommodate the geometric changes in the surface contour, as the two halves of the bulge telescope with each other, and still keep the aerodynamic seal.

In profile it would look something like this:


Does a Mexican citizen studying in the US with an FAA license need a visa when landing at airports in Canada? I'm from Mexico but worked in San Francisco for 4 years under a TN Visa. During that time I learned how to fly and obtained a PPL and then an IFR rating.

I'm now living in Boston getting a Masters Degree under an F1 Visa. I'm interested in flying into Canada. Canada requires visas for Mexican citizens, but a friend claims that there's an exception for pilots. I only want to check out Montreal, so I would be in Canada for 48-72 hours max.

What's a good resource to see visa requirements for pilots from different countries flying into countries other than their own?

Thanks!

You should call the Embassy of Canada in Mexico for advice on your situation. They will best be able to advise a Mexican passport holder on their entry requirements. Their number is +52 55 5724 7900.


What advantage might interplane-strut mounting offer to ailerons, on the Curtiss Model F? Glenn Curtiss's 1912-1918 Model F biplane flying boat has large ailerons on the struts between the wings, not contiguous with any other flying surface.  Did this aileron position have any advantage that either he knew of or that we now know?
[Per SupBruh's comment, contrast this position to conventional upper-wing position.  Lower wing was rare even then, and particularly for a seaplane where an aileron this big would hit the water when deflected.]
He knew about wing warping, so he knew the effectiveness of camber (hinging an aileron at a wing's trailing edge) as compared to just changing an airfoil's angle of attack.  He knew how to make a hinge: this aircraft uses them at rudder and elevator.
He also knew about modern ailerons: in 1908 he flew an aircraft with them.
Maybe he chose such a large chord for the ailerons to try to increase their authority.  Photos suggest that the airfoil was just a flat plate, which stalls at a deflection angle much less than that of a conventional aileron.  But the drag from a stalled aileron that big would produce scary adverse yaw.

Disclaimer: I can only speculate, having no direct involvement with the development of the Curtiss Model F.
Stick forces were not really an issue with the small and slow early aeroplanes. As both size and speed went up, they would become a design consideration first because the pilot strength is lowest for lateral motion of the stick or control horn. With more aerodynamic experience, elaborated ways of reducing stick forces were employed.
My explanation, therefore, is that this is an early attempt at reducing stick forces. Hinged at the trailing edge, the complete chord length of the aileron would be behind the hinge line and no offsetting moment could be produced. Also, being part of the wing, ailerons hinged at the trailing edge will float up once lift is created. This requires both ailerons to be interlinked with stiff control cables which again raises stick forces, now from friction. Also, this preload from lift limits the effectiveness of a downward deflection of a wing-mounted aileron.
The free-flying aileron, on the other hand, has the advantage of starting with a clean sheet, if you will:

No preload exists, so it will be equally effective in up- and downward deflection.
It is not encumbered by the boundary layer of a wing flying before it, so its neutral axis will be easy to find and be constant over angle of attack, unlike that of a wing-mounted aileron. This was certainly not formulated this way at the time of the design of the Model F, but experience would bring the designers to exactly the same conclusion. The same considerations brought Junkers (more precisely: Otto Mader) to the offset flaps and ailerons in their designs from the late 1920s to early '30s.
With the aileron position between wings, the hinge line can be freely chosen at any chord position. The picture below (source) shows that a small part of the aileron was ahead of the strut, suggesting that the hinge line was not at its leading edge, but set back a bit. This enables the forward part to act as a balance, thus reducing stick forces.

I would expect that the Curtiss Aerorplane Company tried out different hinge line positions, which is easily done with the inter-wing arrangement, and settled on the one shown above, because it reduces stick forces considerably but still produces a clear centering force, which is important for agreeable handling qualities.
I do not think that the inter-wing position would reduce wing flex: Lift forces from the aileron are introduced into the wing by the rear strut, so both torsion and bending are very similar to a wing with ailerons on its trailing edge. To reduce torsion, the aileron would have to be mounted on the forward struts. Then they would even warp the wing in a way supporting the intended rolling moment. I speculate, however, that Curtiss and his engineers maybe considered that option but were afraid of the resulting aerodynamic interference between wings and ailerons.
That the inter-wing position lost against the balanced, wing-mounted aileron is certainly due to the much lower drag of the latter. Note that the inter-wing aileron needs its own rigging. With the increased experience of balancing ailerons, the wing-mounted version lost its main disadvantage and became the overall better solution.


How can one achieve supersonic cruise capabilities without afterburners? I have read that in order to have stealth capabilities of the F22, it was designed such that it could cruise at supersonic speeds without using afterburners, which increase RCS. How is this possible? what is the technology behind this?

A normal jet engine has subsonic flow throughout. This avoids shock problems such as choking or excessive acoustic noise.
A conventional afterburner accelerates the exhaust flow to supersonic speed, allowing it to push the plane past the speed of sound. It is placed after the turbines in order to avoid those shock problems.
A supercruise engine must deliver supersonic exhaust flow without using an afterburner. Luckily, in a hot gas the speed of sound is much higher than in a cold gas. So as long as the exhaust is not cooled before exit, its high exit velocity stays subsonic within the engine and only "looks" supersonic relative to the outside air.
The problem with this is that you cannot obtain the usual benefits of mixing bypass air with it to increase its mass flow and thermodynamic efficiency, because that would cool it and create a standing shock wave across it, slowing it to subsonic speeds.
The end result is a bit of a design compromise; relatively high mass flow through the core, relatively low bypass ratio, some sacrifice of efficiency.


how can i help the air force at this age if I'm only 13 years old? I'm young, 13 to be exact. I'm not old enough to join and I really want to help the brave men and women in the skies.How can I help the air force at this age?

As stated by Crossroads, AFROTC is an option. So is the Civil Air Patrol. Both will give you a taste of armed uniformed services life. Otherwise, look into volunteer opportunities locally to support the armed forces. Military.com may be a good start on researching charity organizations. Just be respectful in the forums, please.


Is it legal to fly without a transponder? Everything is legal / airworthy.
Except:
Transponder is installed.  It does work.  It has NOT been inspected in any time frame that would show it is properly maintained.
Flight is
Golf, Echo, Delta < 2500 AGL
Can I shut off the transponder and fly legally?

Yes, you can in the US in Class D, E & G airspace according to 14 CFR 91.215. You will need to placard the transponder INOP, and make a note in the aircraft logbook. But, you must stay out of any Mode C Veils, and further than 30 miles from Class B airports. Also, stay below 10,000 feet MSL unless that means you are below 2,500 feet AGL. However, you can request a deviation to 91.215 from ATC in advance.


How is the FPA (flight-path-angle) computed? How is FPA computed by the Auto-pilot to follow the  desired FPA? One part is clearly VS, is the other part IAS or Ground speed? Where does Ground speed come from?

The flight path is a path defined with respect to the ground. Therefore, the flight path angle must be computed with the ground speed:

The flight path angle $\alpha$ is calculated by the on-board computers with:

$$ \alpha = \text{arctan} \left( \frac{V/S}{\text{GS}} \right) $$

The source of the ground speed would in general be aircraft dependent, but for an airliner this would come from the Air Data Inertial Reference System (ADIRS). See also How is the actual ground speed of an airliner measured?

Some non-precision approach charts will also have a table with required vertical speeds for various ground speeds to maintain the target flight path angle. This is particularly helpful if your aircraft cannot fly a given FPA itself. This is an example from Amsterdam Schiphol (EHAM) VOR Approach for runway 09:

If you e.g. fly with a ground speed of 150kt on this approach, you would just dial in 800ft/min and you would get the desired 3° FPA.


Are there regulations for the field of view from cockpits? Are there any design or ergonomic regulations with regard to the pilot's vertical and horizontal vision angles from the cockpit?

For example, pilot should see space 30 deg. above and 20 deg. below horizontal.

The certification specification for aircraft are deliberately a bit vague on the topic. This allows manufacturers to come up with creative solutions that may have been prohibited if specific angles where required in the specification.

For large aircraft, EASA has requirements CS25.773 in the Certification Specification 25 (CS25) PDF which is included below this answer. The FAA requirements are similar in FAR 25.773.

To make sure that there is an agreed standard on what is acceptable to the certifying authorities, acceptable means of compliance have been published. Manufacturers may deviate from the AMC's if they have good arguments for it.

An example of the FAA AMC on this topic can be found in AC25.733-1 (PDF).
The FAA document refers to standard ARP 4101/2 which is the successor of SAE 580B (unfortunately you have to pay for these documents).

From this answer and the image there contained, you can see how the outside visual field of view of the cockpit of the A320 family compares to the 580B standard.

  CS 25.773 Pilot
  compartment view (See AMC 25.773)  a) Non-precipitation conditions.
  For nonprecipitation conditions, the following apply:

  (1) Each pilot
  compartment must be arranged to give the pilots a sufficiently
  extensive, clear, and undistorted view, to enable them to safely
  perform any manoeuvres within the operating limitations of the
  aeroplane, including taxiing, take-off, approach and landing.

  (2)
  Each pilot compartment must be free of glare and reflection that could
  interfere with the normal duties of the minimum flight crew
  (established under CS 25.1523). This must be shown in day and night
  flight tests under non-precipitation conditions.

  (b) Precipitation
  conditions. For precipitation conditions, the following apply:

  (1)
  The aeroplane must have a means to maintain a clear portion of the
  windshield during precipitation conditions, sufficient for both pilots
  to have a sufficiently extensive view along the flight path in normal
  flight attitudes of the aeroplane. This means must be designed to
  function, without continuous attention on the part of the crew, in –

  (i) Heavy rain at speeds up to 1·5 VSR1, with lift and drag devices
  retracted; and

  (ii) The icing conditions specified in Appendix C and
  the following icing conditions specified in Appendix O, if
  certification for flight in icing conditions is sought (See AMC
  25.773(b)(1)(ii)):  (A) For aeroplanes certificated in accordance with CS 25.1420(a)(1), the icing conditions that the aeroplane is certified
  to safely exit following detection.

  (B) For aeroplanes certificated
  in accordance with CS 25.1420(a)(2), the icing conditions that the
  aeroplane is certified to safely operate in and the icing conditions
  that the aeroplane is certified to safely exit following detection.

  (C) For aeroplanes certificated in accordance with CS 25.1420(a)(3),
  all icing conditions.

  (2) No single failure of the systems used to
  provide the view required by subparagraph (b)(1) of this paragraph
  must cause the loss of that view by both pilots in the specified
  precipitation conditions.

  (3) The first pilot must have a window that:

  (i) is openable under the conditions prescribed in subparagraph
  (b)(1) of this paragraph when the cabin is not pressurised;

  (ii) provides the view specified in (b)(1); and

  (iii) gives sufficient
  protection from the elements against impairment of the pilot's vision.

  (4) The openable window specified in sub-paragraph (b)(3) of this
  paragraph need not be provided if it is shown that an area of the
  transparent surface will remain clear sufficient for at least one
  pilot to land the aeroplane safely in the event of -  (i) Any system
  failure or combination of failures, which is not, Extremely Improbable
  in accordance with CS 25.1309, under the precipitation conditions
  specified in sub-paragraph (b)(1) of this paragraph.  (ii) An
  encounter with severe hail, birds, or insects (See AMC 25.773(b)(4)).

  (c) Internal windshield and window fogging. The aeroplane must have a
  means to prevent fogging to the internal portions of the windshield
  and window panels over an area which would provide the visibility
  specified in sub-paragraph (a) of this paragraph under all internal
  and external ambient conditions, including precipitation conditions,
  in which the aeroplane is intended to be operated (See AMC 25.773(c)).

  (d) Fixed markers or other guides must be installed at each pilot
  station to enable the pilots to position themselves in their seats for
  an optimum combination of outside visibility and instrument scan. If
  lighted markers or guides are used they must comply with the
  requirements specified in CS 25.1381.

Many aircraft have eye position gauges in the cockpit that pilots can use to adjust their seat for optimal view. They either try to line up little colored balls or look through a small sight. Here are a few examples:

Airbus A320

Image Source

Cessna Citation

Image Source

ATR-72

Image Source

McDonnell-Douglas MD-80

Image Source


What are the differences between an OBS, a CDI, a Heading indicator, and an HSI? What are the differences between an OBS, a CDI, a Heading indicator, and an HSI? As far as I can tell they all use VORs. Why would 4 different version of the same instrument be invented? Is the HSI the most advanced of the 4 because it shows the most detail?

Check out this manual from the FAA on flight instruments

Heading Indicator:

The heading indicator is fundamentally a mechanical
instrument designed to facilitate the use of the magnetic
compass. Errors in the magnetic compass are numerous,
making straight flight and precision turns to headings difficult
to accomplish, particularly in turbulent air. A heading
indicator, however, is not affected by the forces that make
the magnetic compass difficult to interpret.

Heading Indicators are not VOR related. They simple provide an alternative to the compass and are generally used when the compass reading may be inaccurate (non straight and level flight). Due to their functionality they need to be periodically aligned with the compass.

Course Deviation Indicator:

A course deviation indicator (CDI) is an avionics instrument used in aircraft navigation to determine an aircraft's lateral position in relation to a course. If the location of the aircraft is to the left of course, the needle deflects to the right, and vice versa.

The OBS (Omni Bearing Selector) knob is on the CDI, it is not its own instrument. The knob allows the selection (via the outer ring) of the radial (course) you wish to track from a VOR ground station. When tracking a radial you only track left/right deviation and thus only a single needle is required (the first picture you have). For instrument flying you also need to track the glide slope for an approach and thus vertical deviation may also be displayed on a CDI. When on an instrument approach the CDI is used to track the left/right deviation from the runway (not a VOR).

Horizontal Situation Indicator (HSI):
Is a CDI and Heading Indicator packed into one unit. it provides both left right deviation along with glide slope information as well as heading indication in turns. Many HSI's are coupled to auto pilots and may allow course selection via a heading knob if they are connected to do so. The HSI is not any more advanced than the sum of its counter parts but it is more complex and to a new pilot may be hard to read.


How to calculate the stability derivative of Pitch Moment with respect to AOA rate? How to separate the stability derivatives: $C_{M\dot \alpha}$ and $C_{Mq}$.

I can imagine a $q=const, \dot \alpha=0$ movement like this

But what a $\dot\alpha=const, q=0$ movement would be look like?

$q = 0$ means no change of pitch angle. You also have a constant rate change in AoA ($\dot{\alpha} = const$).

The difference between the pitch angle ($\theta$) and AoA ($\alpha$) is the flight path angle ($\gamma$).

$\theta = \alpha + \gamma$

From this it follows that the flight path angle changes opposite to the change of change of AoA.

$\dot{\gamma}=-\dot{\alpha}$

This is not a manoeuvre that will happen in real life. An approximation of such a situation can happen when after a brief but strong pull-up the pitch angle is kept constant while the path angle of the aircraft is still increasing. The rate of change of the AoA will not be constant in such a manoeuvre.


What is this "Micro T-tail" on the F-102? I just noticed this unusual thing on the F-102 Delta Dagger. It looks like a micro T-tail. What is it actually, and what is its purpose?

The T tail is the VHF Antenna Localizer of the AN/ARN-31 Instrument Landing System.

source: Convair F-102 Delta Dagger Pilot's Flight Operating Manual


How well can a helicopter handle someone jumping onto it while taking off? I see it a lot in movies, curious how say...an Robinson R44 would respond to a 200-pound man jumping and grabbing onto the skids while it's ~10ft off the ground and in the process of taking off??

Edit:
more specifically, how dramatic would the effect be?
with Hollywood physics, the chopper would stumble as if the hand of god lightly slapped its side?

The total mass of a light helicopter is about 1000 kg (depending on type and actual payload, of course). The 200 pound guy adds about 10%  to the total mass (and weight). The skids are relatively close to the centre of gravity (COG).

Immediate impact

Kinetic energy

In terms of mechanics, the jumping man will have a mostly inelastic collision with the helicopter, and he will transfer both, kinetic energy and impulse accordingly. One may simply choose the helicopter as reference coordinate system to calculate the resulting change of (vertical) speed for the helicopter:
$$\Delta v_\rm{H} = \frac{m_\rm{G} \Delta v_\rm{G}}{m_\rm{H}+m_\rm{G}} = \frac{1}{11} \Delta v_\rm{G}  \ \ \ \ \ \ (m_\rm{H}=1000 \rm{\,kg},\ m_\rm{G}=100 \rm{\,kg})$$
In the movie, the jumping man will just make it. The relative speed will be close to zero, and divided by 11 will be even closer to zero. If he had a significant speed relative to the skid, he would not be able to hold himself.

The transfer of kinetic energy is negligible for the stability of the helicopter.

Added weight

The total weight of the aircraft increases by 10%. This sudden change creates a jolt which is clearly perceptible inside the helicopter, also suddenly changing the vertical acceleration. The (vertical) speed is the mathematical integral of the (vertical) acceleration. The speed will steadily change. The same holds true for the (vertical) position of the aircraft, which is the mathematical integral of the (vertical) speed.

In other words, the inertia of the bigger mass will prevent sudden  change of vertical speed. For the pilot, this 10% disturbance will be very obvious, and he needs to counteract.

(Note that there was a related question recently: What would happen if a plane lost half of its weight instantly?)

Imbalance

The imbalance caused by the guy hanging somewhere else than under the COG creates a torque. This torque creates an angular acceleration. This angular acceleration integrates to angular speed, which integrates to roll and pitch respectively. While the angular acceleration starts suddenly, the angular speed can only change steadily.

The helicopter will not loose its attitude in a fraction of a second, like it happens in Hollywood movies.

Countermeasure

The pilot will use the Collective control to counter the added weight, and the Cyclic control to counter roll and pitch. Provided that the pilot reacts timely enough, it should be possible to stabilize the helicopter. 100 kg additional mass should not prevent the helicopter from climbing, unless it was already overloaded and without safety margins before the 200 pound guy arrived.

More critical is the torque created by the offset load and the resulting COG shift. I am not aware of the roll and pitch performance of small helicopters, but I believe that they are able to fly with somebody standing or hanging on a skid. Asymmetric load of this magnitude will likely impact stability and manoeuvrability, but will not necessarily cause a crash.

If the fearless 200 pound guy instead would jump and hold to the tail skid, the additional weight would be much further from the COG, and the outcome probably be disastrous.

Safety

This does not mean that it is safe to continue the flight with the 200 pound guy hanging anywhere on one skid. Pilots always need to verify if the amount and distribution of the load is within the performance limits of their aircraft. See "Helicopter - Weight & Balance, Performance" for some explanation and example (note Figures 2-5, 2-6, and 2-7). Depending on the helicopter performance and the load distribution before the guy jumps, the new distribution may be within the specified safe longitudinal and lateral COG envelopes, or not.


What's the rule of thumb for power and rpm in a constant speed prop? I think I understand the relationship between the power lever and the RPM lever in an aircraft with a constant speed prop thanks to this question. However, what'd be a general rule of thumb for flying a small aircraft (e.g. Cessna 170) that has a variable-pitch propeller?

Edit:
I'm flying a Cessna 170 that has been modified to fit a constant speed prop. What I'm trying to determine are the general recommendations for flying with them. Things like: On takeoff you should use full power & full rpms, on cruise lower power to 75% but keep full  rpms, etc. I'm not sure if there are general recommendations to begin with.

The answer to your question is actually really simple: do not exceed the limitations specified in the POH.

Really, that's it!  Note that LIMITATIONS are not the same as RECOMMENDED PROCEDURES.  Recommended procedures are just that: recommendations.  Limitations (exclusively from the "limitations" section of the POH) are the hard and fast rules you must adhere to.

Full RPM in Cruise
As long as your POH does not impose a limitation on takeoff RPM (the Seneca II has such a limitation, for example), then there is nothing wrong with using max RPM from takeoff to shutdown. You won't damage the engine.  If the POH provides a limitation on engine RPM (specifically in Section II of the POH), you must adhere to that limitation.  It's common to see a 5 minute "max RPM" limitation on some turbocharged engines.  Great, takeoff at max RPM then pull the engines back to the top of the green arc until you land.  Easy!

Manifold Pressure & RPM
Mike Sowsun said:
"You should always follow the manufacturer's procedures but a general rule for direct drive normally aspirated engines is to keep the manifold pressure less than the RPM for cruise power. (eg. 24 inches of MP at 2400 RPM)."

If you decide to apply "rules of thumb" to all phases of flight you will be voluntarily handicapping your airplane's full potential.

Some definitions:
Oversquare - manifold pressure > RPM (23" @ 2100 RPM)
Undersquare - manifold pressure < RPM (23" @ 2500 RPM)
Square - manifold pressure = RPM (23" @ 2300 RPM)

Do not embrace the idea that manifold pressure should never, ever exceed the value of the first two digits of the engine RPM (sounds pretty arbitrary when I put it that way, right?).  It actually may be beneficial to run an engine "oversquare" in some cases!  This is another example of why knowing your aircraft's "Section II" limitations is important.  If 23" @ 2100 RPM falls within the limitations, go for it!!  You won't hurt the engine.  Same with 25" @ 2300 RPM or 26.756431" @ 2196.454634 RPM.  I think you get my drift.  As long as your manifold/RPM combination falls within the limitations set out in Section II of the POH, you're golden!!

Now, climbing out on a hot day with a garden variety Lycoming or Continental (like in 170)?  29" @ 2100 RPM probably isn't wise.  30" @ 2700 RPM?  Yeah, that's better!  25" @ 2500 RPM isn't bad but it's no better or worse that 26" @ 2700 RPM or 30" @ 2650 RPM.  Remember, there's nothing special about "square" manifold/RPM values.  I'd routinely run the IO-520 in my Bonanza at max manifold pressure and max RPM from takeoff to cruise and simply leaning to an EGT target as I climbed (and watching CHTs, of course).  Only when leveling off in cruise did I pull it back to an economical setting (sometimes oversquare, sometimes undersquare; always lean of peak).  The engine ran beautifully with good CHTs and incurred no unusual wear.  In fact, the engine's health improved.  Exhaust and plugs became noticeably cleaner and compressions improved.

In cruise, set the power to any combination of manifold/RPM you desire provided that setting falls within the limitations in your POH.  You won't hurt the engine with a valid manifold/RPM setting.  It's possible to put undue stress on a motor with a bad mixture setting, though.  POHs are notorious for giving poor guidance with regard to mixture settings.  Mixture settings require a little more attention above ~65% power but that's another topic entirely.

I recommend that everyone with engine questions read John Deakin's "Pelican Perch" articles.  He's THE source for fact based, accurate engine operation information. He happens to have touched on this "oversquare" myth here.  See Myth #2.

Edit: I credited John Deakin with my linked article.  I was mistaken.  The author of the linked article is Linda Pendelton.  She links to a Deakin article, though.

Mike Busch also addresses the oversquare myth here.


How are fly-by-wire airliners controlled in case of complete electrical failure? In this comment, it is postulated that even fly-by-wire aircraft (Airbus) are demonstrated to fly without any electrical systems.

  All Airbus aircraft are demonstrated controllable with complete electrical failure. They would be pretty difficult to land if the electronics didn't at least partially recover (because the backup only allows controlling pitch and yaw and roll only via yaw-roll stability), but it would still be possible. [...] Jan Hudec Dec 21 '14 at 21:38

My question, assuming complete electrical failure, how exactly is this done? What controls have mechanical linkage (pitch trim? engines? flaps/slats?) Would it be possible, in theory, to land the plane in such a way that some passengers could walk away? (Perfect weather, miles of flat tarmac runways everywhere, cinematic pilot capabilities)

For the complete electrical failure in the aircraft, the following systems have to fail:

The onboard power generation system, usually a synchronous generator has to fail in all the engines.
The APU (Auxiliary Power Unit) has to fail.
The RAT (Ram Air Turbine) should fail to deploy.
The batteries and static inverters should fail (this won't help in controlling the aircraft, just added for sake of completeness).

The probability of this happening is very very low, and can be discounted. It is more probable that some other system (for e.g, hydraulics) fail before this happening. So far, to the best of my knowledge, no complete power loss has been reported in any fly by wire aircraft.

The reason the Airbus aircrafts are controllable in case of electrical failure is due to the fact that the fly-by-wire system has multiple redundancies that offer layered protection:

Normal Law offers all the protections (like stall, load factor etc). This is the system in operation during normal flights.
Alternate Law offers limited protection including stability, load factor and stall protections
Abnormal Alternate Law limits the load factors and offers yaw damping only
Direct Law is the lowest level of fly-by-wire system and directly transmits the pilot inputs to control surfaces, while still giving stall and load factor warnings
In case all these fail, the system reverts to mechanical backup, where pitch control is achieved through the horizontal stabilizer and lateral control is accomplished using the rudder pedals.

In case of mechanical backup, the system will operate as long as hydraulic power is available. In case of electrical failure, as long as hydraulics are OK, the pilot should be able to control the aircraft.

However, usually, if there is no power, there is no hydraulic pressure (except reservoir, maybe) and the control is lost. In case of the Baghdad DHL aircraft, only hydraulics was lost and power was available.

There are some more points to consider in case of total electrical failure.

In case the control surfaces are moved by electric power (like 787), power loss means loss of control.
Power loss implies that the engine thrust cannot be controlled (of course, the engines won't be operational in that case anyway).
Some fly-by-wire aircrafts are unstable by design. In these cases, any power loss will lead to loss of control and crash.
I'm not sure there is any direct mechanical linkage in civil airliners. The amount of force required to operate such a system would be enormous.

Bottom-line is, in case of complete power failure, the aircraft is as good as dead. One example is a Fairchild Swearingen Metroliner (which was not fly-by-wire), that lost complete electrical power due to a lightning strike. The aircraft entered into a uncontrolled flight, which loaded the aircraft beyond limit, resulting in its disintegration.


Why is ARP (Airfield Reference Point) needed? An airport reference point is the centre point of an airport, located at the geometric centre of all the usable runways. The ARP is computed as a weighted average of the end of runway coordinates.

I don't know which country you are referring to.  These are countries that rely on TERPs for instrument procedures.
From the FAA TERPs Order 8260.3D

Definitions

Airport reference point (ARP). The official horizontal geographic location of an airport. It
is the approximate geometric center of all usable runways at an airport.

Page 2-16: The ARP is used to center the MSA on the airport.
Page 3-7:  The ARP is used to determine the distance requirements of remote altimeter settings.
Page 11-5:  The ARP is used to align the FAC with a circling only approach.
Page 14-31: The ARP is used to center the VCOA (Visual Climb over Airfield)


Can one "create" a private interpilot air-to-air frequency to chat? I've been looking for an answer to this for the past couple of hours and can't find anything on the matter. (Yes, I've read this What radio frequencies are used for intercom in formation flying?  , but it didn't answer my question, as I'd like to know about frequencies that are not in use by any authorities or  organisations and are not used for anything official,  such as search and rescue).

A pilot mentioned to me she "created" frequencies to talk in private with her mate (air-to-air interpilot). I found one link that says pilots sometimes use unallocated frequencies to chat , so I assumed she meant that, but I've just read on AOPA that all 760 channels available in the VHF   aviation band are actually allocated (I'm assuming in the USA, as the reference is an FAA circular) even if some are not used at all times.

So, can you "create" a private frequency? If I'm right to assume that that makes no sense, can you join a private frequency (do they exist??) or use an unallocated one to chat privately? In case it's the latter, how does that work if all frequencies are allocated already (or is that just in the USA)?

Thanks a lot for your help

Every frequency is allocated somewhere, in fact the same frequency will be used over and over throughout the world. This works because air band radios are relatively short range, about 200nm at best, so all you really need to do is find a frequency that isn't used anywhere near you and tune to that. This is what formation or group flights do.

That will not be private in the sense that it cannot be overheard, anyone with an air band radio can listen in. It will also not be private in that only you could use it, again anyone could tune into the same frequency for the same purpose. Formations often have secondary frequencies to tune to in these cases, but it's rare they need them.


Is required that your alternate airport has approaches other than GPS approach? I start to read AIM and AC90-105A about alternate considerations.If I have GPS(TSO-129 let’s say),Can I file based on a GPS-based IAP at the alternate airport,and my alternate airport only has GPS approach?

See 9.5 of the referenced document:

  9.5 Contingency Planning for Alternate Airport.
  9.5.1 Alternate Airport Considerations. For the purposes of flight planning, any required alternate airport must have an available instrument approach procedure (IAP) that does not require the use of GPS. This restriction includes conducting a conventional approach at the alternate airport using a substitute means of navigation that is based upon the use of GPS. For example, these restrictions would apply when planning to use GPS equipment as a substitute means of navigation for an out-of-service very high frequency omni-directional range (VOR) that supports an instrument landing system (ILS) Missed Approach Procedure (MAP) at an alternate airport. In this case, some other approach not reliant upon the use of GPS must be available. This restriction does not apply to pilots
  with navigation systems meeting the requirements below.

  9.5.1.1 For flight planning purposes, TSO-C129( ) and TSO-C196( ) equipped users (GPS users) whose navigation systems have fault detection and exclusion
  (FDE) capability, who perform a preflight RAIM prediction at the airport
  where the RNAV (GPS) approach will be flown, and have proper knowledge
  and any required training and/or approval to conduct a GPS-based IAP, may
  file based on a GPS-based IAP at either the destination or the alternate airport, but not at both locations. At the alternate airport, pilots may plan for applicable alternate airport weather minimums using:

  Lateral navigation (LNAV) or circling minimum descent altitude
  (MDA);
  LNAV/vertical navigation (VNAV) decision altitude (DA), if equipped with and using approved barometric vertical navigation (baro-VNAV) equipment;
  RNP 0.3 DA on an RNAV (RNP) IAP, if they are specifically authorized users using approved baro-VNAV equipment and the pilot has verified RNP availability through an approved prediction program.

  Note: If the above conditions cannot be met, any required alternate
  airport must have an approved IAP other than GPS that is anticipated
  to be operational and available at the ETA, and which the aircraft is
  equipped to fly.

  9.5.1.2 Pilots with WAAS receivers, TSO-C145( ) or TSO-C146( ), may flight plan to use any IAP authorized for use with their WAAS avionics as the planned
  approach at a required alternate, with the following restrictions. When using
  WAAS at an alternate airport, flight planning must be based on flying the
  RNAV (GPS) LNAV or circling minima line, or minima on a GPS approach
  procedure, or conventional approach procedure with “or GPS” in the title.
  Properly trained and approved, as required, TSO-C145( ) and TSO-C146( )
  equipped users (WAAS users) with and using approved baro-VNAV
  equipment may plan for LNAV/VNAV DA at an alternate airport.
  Specifically authorized WAAS users with and using approved baro-VNAV
  equipment may also plan for RNP 0.3 DA at the alternate airport as long as
  the pilot has verified RNP availability through an approved prediction
  program. Code of Federal Regulation (CFR) Part 91 nonprecision weather
  requirements must be used for planning. Upon arrival at an alternate, when the
  WAAS navigation system indicates that LNAV/VNAV or localizer
  performance with vertical guidance (LPV) service is available, then vertical
  guidance may be used to complete the approach using the displayed level of
  service.


Is the physical MAX8 design bad because software is required for the aircraft to stay airborne? I'm not an aviator by any means, but one thing that has come up in recent conversations with friends is that the MAX8 is inherently unsafe because alone, unpowered, the craft is not 'aerodynamically stable'.

As we understand it, the new engine configuration means that the plane has a tendency to point upwards, requiring software to constantly point the nose down (which also seems kinda sketchy, cuz.. software). I imagine that if there was nothing to run the software, the nose would raise higher and higher until the whole thing was trying to backflip. I understand it wouldn't go totally vertical, but I guess maybe enough to stall or something else just as bad.

Is this true and is this the only aircraft with this kind of 'software or bust' design?

Edit:

My apologies, this question is probably pretty terrible for the majority of the people on this particular stack, but the thought has come up and been validated enough in conversations that I thought to ask folks here to get a better idea and/or be proven wrong (as has happened). I had no idea about phugoid or any of that kind of thing. I only really have "heavier engines cause the craft to pitch upward requiring software to point downward" and "software requires power to run" to base any kind of premise on. I appreciate your patience.

Just to address a misconception

alone, unpowered, the craft is not 'aerodynamically stable'.

I don't believe this is true.

Unpowered
The problem addressed by MCAS is not specifically unpowered flight but flight when the aircraft has a high angle of attack. Because of the need to mount the wider engines further forward to maintain ground clearance, there is a tendency for the engine housing to cause additional aerodynamic forces that rotate the aircraft in the pitch axis - these forces tend to push the nose up. The forces are higher than on prior 737s.

By "unpowered" you might be thinking more of electrical power than engine power. The two are usually related. However any aircraft like the 737 has multiple electric power generators, if the generators on both main engines fail, there is a Auxiliary Power Unit (APU) that can provide electrical power. If both engines and the APU fail, many aircraft have a ram air turbine (RAT) that deploys to produce hydraulic and/or electric power. If both engines, the APU and the RAT fail, there are batteries that provide enough power for minimal necessary controls for a short while, maybe of the order of 30 mins.
I don't know about the 737, but the 30-year-old A320 family of fly-by-wire aircraft has a mechanical backup mode where the pilot can control the aircraft using purely mechanical means and non-electrical instruments. In 30 years I think the closest any aircraft has come to this was a 2005 A319 incident where the cockpit went dark and I believe the pilot flew for a while without any computerised aids, they quickly restored power and continued to their destination. I know of no reason to think the 737 is more dependent on computers for stable flight.
Even without any electrical power, an aircraft like the 737 ought to be no less "aerodynamically stable" than the earliest 737.

Aerodynamically stable
It is normal for aircraft trim to be adjusted during various phases of a flight. The aircraft is still considered 'aerodynamically stable'. When commencing an unpowered glide, the pilots would likely adjust trim. This applies to almost all aircraft.
It is normal that an aircraft in flight, without manual control inputs and without automated inputs from an autopilot etc, can exhibit undesirable flight characteristics such as a phugoid cycle. An aircraft with this sort of behaviour is normally regarded as aerodynamically stable.
I have not read anything to suggest the 737 NG or MAX series are inherently unstable. Even in an unpowered glide.
So far as I know, the only aircraft that are deliberately made inherently unstable are high-agility fighter aircraft.

Maneuvering Characteristics
MCAS stands for Maneuvering Charactersitics Augmentation System. From what I've read, a large part of the motivation for it was to make the aircraft controls feel the same as an older generation 737 - hence the name. Boeing felt that a pilot getting out of an older 737 could get into a 737-MAX and use & experience the same forces on the control yoke as before when climbing out after take off etc.

Related:

How are fly-by-wire airliners controlled in case of complete electrical failure?

Can large airliners such as a 747 maneuver without electricity?

What went wrong inside Boeing's cockpit?, BBC, 17 May 2019


Does the NTSB ever not follow up a preliminary report? Two years ago, there was a fatal crash in Fredericksburg, VA in which 6 people died in a Beech 95-B55. For some reason, the story struck me, and I wrote a note to myself to follow up on it.

The NTSB published a preliminary report 12 days after the crash (on 8/24/2016) but has not published any report since then. Do investigations sometimes end at preliminary reports, or will they someday follow up with a final report?

The NTSB case is ERA16FA288. I searched the NTSB's "Aviation Accident Database & Synopses" page for all events in Virginia on 8/12/2016 (as well as googling the airplane's tail number), and couldn't find anything after that preliminary report.

As a retired NTSB employee, I can say that reports with an FA number like that one should definitely close out with a probable cause determination, typically within a year.  Two years is an outlier, and the delay is likely attracting some internal attention.  If you really want to find out about the status, you can call 202-314-6290 and ask for the Ashburn field office.  It's probably their case, and the manager should be able to figure out what's holding it up.


Is it true that the red lights on building antennas help the aircraft "detect/visualize" ground objects? I was thinking that red lights on the antennas on buildings help aircraft to see if there are tall objects in the ground. Is this right?

Source

Those lights are used to show obstacles that may interfere with the aircraft's course, such as antennas, buildings, wind turbines, and they are mandatory.
The name of those lights is Aircraft Warning Lights, and here is an article from Wikipedia about them.


Smoking in the cockpit - how is this tracked? A finding in the final report of US-Bangla Airlines Flight 211 crash is that the captain was smoking in the cockpit during the flight (page 46, section 3.1.2 e of the final report). My questions are:

Are all occupants of the aircraft breathing second hand smoke
including the first officer? Smoke detectors do not work in the
cockpit?
More importantly, how would this kind of behavior be tracked and
corrected in the airline industry? Are the Cockpit Voice Recordings
reviewed? Are there systems/policies in place?

Yes, they would be breathing second hand smoke, but aircraft are well ventilated. The other cockpit crew would be exposed to some amount of smoke. The amount that makes it to the passengers from a single cigarette in the cockpit would probably be undetectable.
Smoke detectors are not very effective at detecting cigarette smoke. I believe this is because most of the smoke passes through filters (the fairly ineffective one on the end of the cigarette and the two very effective ones in the smoker’s chest) which remove particulates and it is therefore not very dense. It takes pretty thick cigarette smoke to set one off.
I don’t know about the rules in Bangladesh, but most of the time airlines are not allowed to listen to cockpit voice recordings. In the US that would be a violation of eavesdropping statutes. The US law stipulates that they may only be used for accident investigation purposes and only transcripts of relevant portions may be released publicly. They can be subpoenaed for a trial only if the publicly released transcript is insufficient and

discovery of cockpit voice recorder recordings is necessary to provide the party with sufficient information for the party to receive a fair trial.
ISBA Amendments of 1990, 104 Stat. 4655.

The pilot’s unions are very much against using the recording or transcripts for any other purpose than accident investigation.
It would end up being down to the other crew reporting them. I doubt it occurs often enough for anyone to keep track of the number of reports for it, and i doubt it would be reportable to any aviation authorities. It would be handled internally to the specific airline.


Is 'make small one turn' a standard phrase? I've heard it somehow that some of USAF controllers say this. is the phrase used in real ATC? if it is, is there any other similar phrases?

More standard English, at least in the U.S., would be "make one small turn", but I've never heard such a term used. Also, "small" doesn't explicitly define how much of a turn, and it doesn't indicate the direction of the turn. ATC instructions are usually precise, something like, "turn right 90 degrees for identification." I remember getting that type of instruction from controllers in setting me up for practice PAR approaches (civilian equivalent of GCA) at Kingsley Field, Klamath Falls, Oregon, U.S.A back in 1969. However, in the next 30 years of flying I never heard a like instruction, at least that I remember, for the simple reason that I never had to fly a PAR approach for real.

The abbreviations are:
PAR - Precision Approach Radar
GCA - Ground Controlled Approach


Why is landing not usually a continuous descent? I have noticed on commercial flights (Ryanair, Boeing 737 specifically), that during the last 20 - 30 minutes of the flight, the aircraft alternates between descending and ascending pitch.

Why is this? Why not just gradually descend?

Further info: The route flown was London, UK to Budapest, Hungary.

The plane wouldn't be ascending during the descend sequence. It instead follows a stair-step sequence. The times where the plane remained level may have felt like ascending even though it wasn't. It is very hard to judge that in the passenger cabin.

It is much easier for the pilot to have a sequence of descends to a specific altitude alternating with keeping altitude until the next marker. It also provides a timeline during which he can handle his checklist.

Doing a full continuous descend brings the danger of ending up too high and needing to re-intercept the glideslope from above. This needs more vertical speed and if something goes wrong can end up with the plane undershooting the runway in the worst case. Intercepting from below each time is much safer and makes that the airplane will never descend steeper than the glideslope and the horizontal sections allow for a margin to correct any minor mistakes.

It is also safer to change the configuration of the airplane (flaps/gear) while in level flight rather than during descend. Staying level for a bit also allows the plane to bleed off the airspeed gained during the descent.


Do all 737NG have inerting systems? My understanding is that Boeing 737-600/-700/-800/-900 are all 737NG.

I've read before that the previous generation (737 Classic) can't be used in the USA as they don't have fuel inerting systems.

But do all (or nearly all) 737NG have fuel inerting systems? I'm thinking here about 737NG worldwide, and not necessarily those in the USA.

The Boeing 737 NG series first flew in 1997, but the fuel inerting system was only certified in 2006 according to b737.org.uk (emphasis mine):

Centre Fuel Tank Inerting
To date, two 737's, 737-400 HS-TDC of Thai Airways on 3 Mar 2001 and 737-300 EI-BZG operated by Philippine Airlines on 5 Nov 1990 have been destroyed on the ground due to explosions in the empty centre fuel tank. The common factor in both accidents was that the centre tank fuel pumps were running in high ambient temperatures with empty or almost empty centre fuel tanks.
Even an empty tank has some unusable fuel which in hot conditions will evaporate and create an explosive mixture with the oxygen in the air. These incidents, and 15 more on other types since 1959, caused the FAA to issue SFAR88 in June 2001 which mandates improvements to the design and maintenance of fuel tanks to reduce the chances of such explosions in the future. These improvements include the redesign of fuel pumps, FQIS, any wiring in tanks, proximity to hot air-conditioning or pneumatic systems, etc.
737s delivered since May 2004 have had centre tank fuel pumps which automatically shut off when they detect a low output pressure and there have been many other improvements to wiring and FQIS. But the biggest improvement will be centre fuel tank inerting. This is universally considered to be the safest way forward, but is very expensive and possibly impractical. The NTSB recommended many years ago to the FAA that a fuel tank inerting system be made mandatory, but the FAA have repeatedly rejected it on cost grounds.
Boeing has developed a Nitrogen Generating System (NGS) which decreases the flammability exposure of the center wing tank to a level equivalent to or less than the main wing tanks. The NGS is an onboard inert gas system that uses an air separation module (ASM) to separate oxygen and nitrogen from the air. After the two components of the air are separated, the nitrogenenriched air (NEA) is supplied to the center wing tank and the oxygenenriched air (OEA) is vented overboard. NEA is produced in sufficient quantities, during most conditions, to decrease the oxygen content to a level where the air volume (ullage) will not support combustion. The FAA Technical Center has determined that an oxygen level of 12% is sufficient to prevent ignition, this is achievable with one module on the 737 but will require up to six on the 747.
The Honeywell NGS was certified by the FAA on 21 Feb 2006 after over 1000hrs flight testing on two 737-NGs. Aircraft have been NGS provisioned since l/n 1935 and it has been installed since l/n 2620 onwards. The NGS requires no flight or ground crew action for normal system operation and is not dispatch critical.

So all older NGs were built without an inerting system. According to this article, the FAA required new models since 2008 to have an inerting system and retrofitting of all 737s until 2018 (emphasis mine):

The headaches are hitting Boeing 737 operators, which make up the bulk of the early adopters among those required to comply with the FAA’s Fuel Tank Flammability Reduction (FTFR) rule. The rule, passed in 2008, called for new-production versions of the affected models—737s, 747s, 757s, 767s, 777s, Airbus A300s/A310s, A320-family models, A330s and A340s—to have fuel tank inerting or flammability reduction systems installed starting in late December 2010. It also required airlines to retrofit half of their affected fleets with an approved system by 2015 and complete the rest by 2018. The phased compliance led operators to prioritize their largest subfleets to ensure they met the first deadline, putting 737s at the top of the list.

It is quite possible that not every airline worldwide has completed this retrofitting.


How do turbofan nacelle lengths compare? For example, compare the JT9D and the PW4000 below (both from Pratt & Whitney, both on a 747):

(Left, Right) The PW4000 has a longer forward nacelle, and a covered exhaust cone.

On the inside—apart from optimizations—they're the same engine:

(Flight) Comparison from an article titled Son of JT9D takes shape. (Click image for larger size.)

From the Airbus A330 Wikipedia article:

All three engines above on the A330 adhere to the same noise restrictions. Apart from what it says under the CF6, all of them feature an exhaust cone that converts the annular exhaust to a circular one to reduce drag.

So, is the choice merely cosmetic/branding, or is there a trade-off of sorts?

Based on the two comparisons above, I'm leaning toward ruling out noise suppression, and internal engine design.

Meeting noise regulations is the primary reason for using a long nacelle. Some engines may not need it. Since it adds weight and drag it is not used unless required. Use may be partially offset by improvement in efficiency, but this does not normally justify usage on its own.

If a particular engine design does not meet the specification, the long nacelle can block certain emissions 90deg to the engine axis which might make the installation compliant. Noise is generated where flows of dissimilar speed mix.

flow from a core mixing

An extended nacelle encloses noise from the instabilities, shielding an observer abreast the noise source where certification measurements are made. A short nacelle provides no shielding.

The engine installation has to meet noise requirements when it is certified for use on an aircraft. Some manufacturers surpass the requirements, attempting to appeal to customers that might be more noise sensitive. Rolls claims to have the quietest installation on the 330 and they are the only one with the extended nacelle. The underlying engines differ in design; they also differ in noise output. It wouldn't surprise me if the 700 core failed to meet the reg with a mid nacelle, exceeded it with the long, and the marketers turned necessity into a feature. The Trent 7000 is developed from the 787's Trent 1000 and has a different core and its installation on the A330neo
uses a mid length nacelle.

A similar but less critical situation exists for the flow from the front fan. The short nacelle on your 747 example would not provide as much noise shielding from the front fan as the mid length nacelle. The PW4000 is a derivation of the JT9D, so it is not the same engine as you state. More importantly, its certification on the 747 took place some twenty years after the JT9D under more strict noise regulations, hence the longer nacelle.


What ILS type approach my flights landing could be? I had one of the foggiest landing experiences recently and I'm interested if any of you could guess what type of ILS could it be like CAT I,II,IIIA or IIIB?
So the METAR issued 9 minutes before my flights touchdown stated RVR as 100 meters and the METAR issued 21 minutes after the landing stated RVR 750 meters.
The aircraft type is A321NX IndiGo Airlines and Airport VILK the RWY is 27.
Here are the METAR and TAF reports ..it could be wrong but I have just tried to gather them with the information I had so I'd love If someone could decipher it for me please !
METAR REPORTS
(After Landing and Deboarding)
SA 02/02/2021 03 : 30
METAR VILK 020330Z 00000KT 0100 R27/0750 FG NSC 11/08 Q1020
BECMG 0150 FG=
(During Approach and Landing) [Touchdown at 03:09]
SA 02/02/2021 03 : 00
METAR VILK 020300Z 00000KT 0000 R27/0100 FG VV/// 08/07 Q1019
NOSIG=
(During Holding Pattern)
SA 02/02/2021 02 : 30
METAR VILK 020230Z 00000KT 0000 R27/0075 FG VV/// 08/06 Q1019
NOSIG=
Below are the TAF reports for the flight -:
TAF VILK 020200Z 0203/0212 VRB02KT 0050 FG VV///
BECMG 0204/0206 0800 MIFG FG NSC BECMG 0207/0209 32004KT 2000 HZ=
TAF VILK 012300Z 0200/0209 00000KT 0200 FG VV///
BECMG 0204/0206 0800 MIFG FG NSC BECMG 0207/0209 32004KT 2000 HZ=

The 3 METARs all indicate extremely poor visibility. The first one (02:30Z) said:

0000 R27/0075 FG VV///

which means visibility less than 50m (0000), Rwy 27 RVR 75m (R27/0075), fog (FG) and vertical visibility not measured (VV///).
The second METAR (03:00Z) still reports visibility less than 50m, but RVR has improved to 100m. The Airbus A321 is certified for CatIIIB down to RVR of 75m (Airbus getting to grips with CAT II / CAT III operations), so technically an approach would have been allowed before, but note that the METAR is only updated every 30 minutes. The pilots were probably informed by the tower or approach controller about the actual current RVR value.
After landing, the third METAR (03:30Z) already shows improved visibility of 100m and an RVR of 750m, indicating that the fog has started to clear.

Here are the minima for the Cat II/III ILS Rwy 27 approach at VILK (Lucknow):

The Cat II is out of the question with a required RVR of 300m (or 350m without autoland in Cat D aircraft). The Cat IIIA would have required at least 175m RVR.
Since the RVR was reported as 100m before landing, the pilots must have prepared for a Cat IIIB ILS approach with autoland. Once the pilots verified that the requirements for a Cat IIIB approach are fulfilled, it does not really matter if the RVR gets a bit better by the time they land, so even if it was 200m at the time of landing, the approach would have been performed with Cat IIIB.

Landings with Cat IIIB seem to be quite common in India according to bangaloreaviation.com:

On the domestic side, only the A320 operators Air India (NACIL-I), GoAir, IndiGo, and Kingfisher have most of their pilots Cat-IIIB certified. Boeing 737 operators Jet Airways, JetLite, and SpiceJet have their pilots certified to the lower Cat-IIIA standard (175 metres runway visibility).
[...] not surprising since the Airbus A320/A319/A321 comes with Cat-IIIB capability built-in, [...]


What are the standard ATC light signals and emergency messages? Apart from 'mayday' which other common emergency messages are used? Is there any regulation regarding them?

Any other light are used by ATC than these? : https://learntofly.ca/wp-content/uploads/2010/11/ATC-Light-Gun-Signals.gif

Is it the same Emergency messages and  Light signals used worldwide or are they different US-Europe ?

Those signals are regulated by ICAO Annex 2 rule of the air:
https://www.icao.int/Meetings/anconf12/Document%20Archive/an02_cons%5B1%5D.pdf

Therefore international.Some other ground signals are indicated there but as far as light signals the ones you showed are the only ones.


Why do some companies perform their freight flights only during the night? I heard that for example FedEx among others performs the majority of their flights during the night, the same goes for TNT. Is the reason for that is that during the day all of the freight is being collected and then loaded for delivery in the evening? Or is there another reason?

As the previous answers have stated, their schedules are determined by what best suits their needs. However, those schedules can be complicated by contractual and curfew requirements.

A contractual example: Thousands of expatriate Brits live in the south of Spain. They want their morning London papers. We would depart Stansted (just north of London) as soon as possible. We were contractually committed to have the load to Barcelona by 07:00 local, with huge penalties if we failed (the papers were worthless by noon), and then on to Palma de Mallorca. Hopefully by now, they transmit the papers electronically and print them locally.

A curfew example: A cargo flight departing Hong Kong bound for Chitose, Japan (refuel there then on to Anchorage). The old Kai Tak airport at Hong Kong had a 23:00 local curfew; Chitose had a curfew until 06:00 local. The solution to that was to depart Hong Kong just before the curfew, land at Taipei and park for a couple of hours (I forget the exact time), and then continue to Chitose to arrive just after 06:00 local.

All Japan airports at the time had a curfew from 23:00 local to 06:00. You could go out to the south end of the airport just before 06:00 local, and set your watch by the first arrival of what was tens of aircraft, both passenger and cargo, whose departure time was determined by the need to arrive as soon as possible after the airport opened


Is it possible to know why an airline operates specific equipment on certain routes? I've spent far too long staring at flight tracking sites, and occasionally I think I'll notice some pattern in what types of aircraft a given airline uses for certain scenarios/routes.

For example, Delta seems to operate a lot of MD-88's on short-haul routes that other airlines would likely use ERJs or CRJs on. They also seem to use 757s on quite short hops (ATL to southeastern cities ~1hr away).

Another example would be why British Airways operates 747s to some cities, and 777s to others, and exactly how they decide where to use which aircraft.

Is there a good reference for figuring out the reasoning behind why airlines use a given aircraft for a given route? Or are there too many different factors and too much corporate secrecy to really know for sure?

There are many factors, but you can often predict what class of plane will be used for a particular route by the distance and demand.

For smaller cities, they want to fill the planes, but they also need several flights per day to cover the fixed costs of serving that airport (and make things convenient for customers), so it's often better to have a commuter jet bouncing to the nearest hub and back several times per day day than one large plane that carries an entire day's worth of passengers in one shot.  For larger non-hub cities, they'll do roughly the same thing but with mid-size planes.

Between hubs, they'll run the largest narrow-bodies to connect all the various small cities not served by a common hubs, plus hubs themselves tend to be large cities with plenty of native demand too.

For international, they'll run wide-bodies because they need higher fuel capacity, and there's rarely a convenient time for customers due to the long flight times combined with crossing several time zones, so you might as well pack them into as few planes as possible.

Notably, some carriers fly several different types, each optimized for specific route types, while others fly just a few types (or even just one) because that makes maintenance, pilot training and fleet scheduling easier--but may limit what kinds of routes they can fly profitably.  When airlines merge, they'll usually have similar fleets--and in cases where they don't, they'll quickly start dumping types they don't like and replacing them with types they do.


What is the difference between a waypoint and a significant point in an airspace? I know ATS routes are made up of waypoints, but what are Significant Points used for? Is there a difference, or are they really just two names for the same thing?

According to ICAO PANS-ATM (Doc 4444) 16th Edition,
Waypoint is a type of significant point.
Mentioned in Chapter 1 - Definition as

Significant point :- A specified geographical location used in defining an ATS route or the flight path of an aircraft and for other
navigation and ATS purposes.  Note.— There are three categories of
significant points: ground-based navigation aid, intersection and
waypoint. In the context of this definition, intersection is a
significant point expressed as radials, bearings and/or distances from
ground-based navigation aids.
Waypoint is defined as a specified geographical location used to define an area navigation route or the flight path of an aircraft
employing area navigation.

So in short waypoint is a significant point used to define an area navigation route or the flight path of an aircraft employing area navigation


If I buy my own aircraft in which to earn my PPL, does my instructor need to be certified to fly the type of aircraft I own/am training in? It seems the most cost-effective way to earn my PPL is to purchase my own plane (with the intention to keep it for quite some time). I believe I would therefore need to find a CFI that is certified for that aircraft type, correct?

You are sort of correct. For the ground instruction for your basic Private Pilot Certificate, it would not really matter. For the actual flight instruction, the CFI has to be certificated for the category and class of aircraft in which you are being trained by them. If the aircraft is a taildragger, high performance, and/or complex aircraft, the CFI will need an endorsement in their logbook from another CFI showing that they have been trained for that scenario. If the aircraft requires a type rating (which almost no trainer aircraft does), the CFI will need a type rating on their certificate in that aircraft as well. Those aircraft requiring a type rating are generally defined by the FAA as:

(7) Aircraft type ratings—
(i) Large aircraft other than lighter-than-air.
(ii) Turbojet-powered airplanes.
(iii) Other aircraft type ratings specified by the Administrator through the aircraft type certification procedures.

Remember, the above explanation applies to the instructor’s Pilot Certificate for them to have the privileges to act as PIC while flying. The instructor’s CFI certificate is a separate certificate allowing them the basic privileges of instructing. The categories and classes listed on a CFI certificate are a little more general than those listed on a Pilot Certificate. An instructor will need both certificates to give the actual flight instruction in flight in the air. Ground instruction is different.
Most people learn to fly in something along the likes of a Cessna 150, 152, 172, 177, or (in some rare cases) 182. The Piper Cherokee line is another popular trainer. Even Cirrus has a line of aircraft that are very suitable as trainers. Any aircraft around that size or smaller is a great start.
As long as the CFI has an ASEL (Aircraft Single Engine Land) class rating on their Pilot Certificate and an ASE (Aircraft Single Engine) rating on their CFI certificate, they can instruct you in almost all aircraft typically used as trainers. If the aircraft in which you want to train is a float plane, the instructor will need an ASES (Aircraft Single Engine Sea) class rating on their Pilot Certificate. If the aircraft is a multi-engine, the CFI will need a multi-engine class rating (AMEL or AMES) as well as have a Multi-Engine Instructor certificate. If the aircraft is a rotorcraft, that falls into a different category than the above aircraft. Gliders also fall into a totally different category. So do balloons.
One caveat is that some CFIs are limited to training students for the Sports Pilot Certificate, only. While a regular CFI can train students for the Sport Pilot Certificate, a Sport Pilot CFI can not train students for the Private Pilot Certificate. Although the hours acquired in one can apply to the other in the same category and class, the Sport Pilot CFI can only endorse students for that specific test and checkride.
For a more in depth description of aircraft category, class, and type ratings as they apply to pilot certificates, please see Title 14 of the Code of Federal Regulations (14 CFR a.k.a. the FAR/AIM) Part 61.5. Especially pay attention to Subpart (c) pasted below.

(c) The following ratings are placed on a flight instructor certificate when an applicant satisfactorily accomplishes the training and certification requirements for the rating sought:
(1) Aircraft category ratings—
(i) Airplane.
(ii) Rotorcraft.
(iii) Glider.
(iv) Powered-lift.
(2) Airplane class ratings—
(i) Single-engine.
(ii) Multiengine.
(3) Rotorcraft class ratings—
(i) Helicopter.
(ii) Gyroplane.
(4) Instrument ratings—
(i) Instrument—Airplane.
(ii) Instrument—Helicopter.
(iii) Instrument—Powered-lift.
(5) Sport pilot rating.


Is there a 'common courtesy' distance that should be complied with when initiating contact with ATC for class D airspace? Some background: I'm a student pilot preparing for an upcoming stage check involving XC diversions and have been trying to visualize different scenarios of what I'd need to do when diverting. One case I was thinking about is if you're flying, say, directly above class D airspace (in this example, maybe 3500 ft) and intend to divert there, is it considered acceptable to call the tower while directly overhead, or are you expected to be further out laterally before making an initial call?
I apologize if this is a pretty unusual question, but I want to make sure I'm not violating any unspoken rules.
To illustrate what I mean, assume I want to land at KLGB. Should I call overhead (red dot) or is it advised to get some lateral distance first (to blue dot) and then call?

To answer the question in the title, the AIM 4-3-2 says:

When operating at an airport where traffic control is being exercised
by a control tower, pilots are required to maintain two-way radio
contact with the tower while operating within the Class B, Class C,
and Class D surface area unless the tower authorizes otherwise.
Initial callup should be made about 15 miles from the airport.

FWIW, I fly out of a class D and usually call 10 miles out, which gives plenty of time to contact ATC. As always, use some judgement: if the airspace is busy and the radio traffic is heavy then call further out. If it's very quiet then calling closer to the airport should be fine.
All that said, the body of your question is about being directly overhead the field. That seems like an unusual scenario (to me) but there's nothing wrong or problematic about it. I'd just call the tower, tell them where I am and that I intend to land, and let them tell me how and where to join the pattern. I can think of two practical points that might come up:

They might assume you have some sort of emergency, so be ready to tell them you don't (unless of course that is your reason for landing there!)
They might give you instructions to join the pattern that are difficult to comply with because they don't know what you and your aircraft are capable of. Or they might ask you how you'd like to join. Have a plan, be ready to say "unable" if you aren't comfortable with their instructions, and if necessary just tell ATC you need to fly some distance away from the airport to get down to pattern altitude.


Could someone use an axe to break through a locked cockpit door? Could someone accomplish entry with an axe, considering how tough cockpit doors are?

Do planes carry axes?

Axes are not carried in the cabin and the door is designed to resist attack using tools available in the cabin

  Fire/crash axe/crowbar. Fire axes were provided to obtain emergency access to areas and parts of the airplane which are not easily accessible (e.g. behind sidewall, electrical or ceiling panels). The handle is insulated to protect against electric shock. In the past, fire axes might be found in the flight deck and in the passenger cabin but on most carriers, in compliance with anti-terrorism regulations and procedures, axes are no longer carried and have been replaced by insulated crowbars in the passenger/cargo compartment.

From http://www.skybrary.aero/index.php/Cabin_Fire


Can a pilot amend a flight plan in-flight? Which information pilot can change in-flight?
For example:

Altitude. Ask to climb higher?
V to Z. VFR rules to IFR (VFR to IFR)?

Anything and everything (well, maybe not the aircraft type...). A flightplan is just that - a plan. The pilot's intentions can change during flight for any number of reasons. Just inform ATC of your new intentions, request a new clearance as appropriate, and ATC will accommodate the request if possible. Happens all the time.


Why do cargo airlines frequently choose passenger aircraft rather than aircraft designed specifically for cargo? Cargo airlines are known to regularly use planes designed primarily for passenger travel.

Why don't they almost exclusively use aircraft designed specifically for cargo?

Price, commonality, and size choice.

A very large proportion of an aircraft's cost is in design and certification. It's followed by the engines, the avionics, and the fuselage. Not much cost can be removed from an aircraft by removing the passenger-specific elements of design. That is done in freighter versions.

Freighter models like the 747-8F already realize most of the possible savings. Second-hand airliners are cheaper still, and they're not hard to convert. Rip out the interior, install cargo securing systems, and fly.

Commonality with airliners means airliner-derived freighters are easier to service and repair anywhere one needs to. And, as Dohn Joe rightly adds, get pilots for; cargo airlines are both a training ground for passenger pilots and a career path of its own.

Finally, there are more airliner models than freight-only aircraft models, so there's more choice of the right payload and range capability.

This reuse of passenger airliners for freight is a great example of efficiency. Passenger airlines tend to have very high utilization, putting lots of cycles on their airframes and lots of fuel through them, so they care for better fuel efficiency, availability, and passenger experience (or at least their expectations when booking, considering the 9-abreast 787) delivered by newer airframes.

Cargo airlines run looser schedules, because their clients don't care much for their flights leaving on time (air freight is usually offered in 2-5 days), which shifts the optimization focus from fuel efficiency towards capital costs. They are able to use up the rest of the airframe's life in a less-critical job, where the oversight is a bit more forgiving and delays due to lower availability are more acceptable.

The An-225 is special in that it occupies a class above every other freighter in capability. It does the jobs nothing else can, but, until recently, the only airframe built has been able to serve the whole world.


Why are many military fighter aircraft designed to fly supersonic? It is my understanding that these aircraft rarely fly at supersonic speeds anyway—the ordnance they carry, the increased fuel burn (even with supercruise), and the increased chance of detection make supersonic flight either hard to maintain or seem unnecessary. In addition, it would seem more beneficial to perform subsonic evasive maneuvers against an incoming missile than to try to outrun it (many air-to-air missiles fly at Mach 3 or higher). Finally, the subsonic Sea Harrier even downed a supersonic-capable Mirage III and many supersonic-capable IAI Daggers to no losses during the Falklands War. Though this can be attributed to the superior pilot training and offensive technology of the Harriers, how come many other aircraft were/are produced with a supersonic requirement?

One reason is interception (with interceptor, not missiles).

Defence is probably more important. Defence with fighters is still important for three reasons:

There are relatively effective counter-measures against surface-to-air missiles. A fighter pilot can adjust the strategy to the counter-measures encountered, missile can't.
In peace or limited conflict situations it is often not known whether a suspicious target is hostile at all and the only way to identify it is to have a fighter fly to it and have the pilot identify it with their eyes.
Fighter can also do other things than use lethal force. In peace time you generally don't want to shot down an intruding military aircraft of another country straight away. Fighter can chase it away from your territory or can try to arrest it (force it to land on your own airbase). And fighters are also used to identify and possibly navigate to safety civil aircraft that lost radio contact.

So when a potentially hostile aircraft is detected entering your territory, fighters are sent to intercept it and help it, arrest it or shot it down depending on what it turns out to be.

If the fighters are slower than the intruder, they may not be able to intercept it at all (they don't usually know where it is flying so they can't wait for it). The faster they are, the larger area they can defend. In this case the interceptors take off without external fuel tanks (as they won't be flying very far) and with only relatively small air-to-air missiles, so they can fly fast.

Conversely if you try to penetrate the enemy territory, flying faster limits the number of fighters that can intercept you. However in this case it is more useful to rely on stealth or flying low to evade detection, so attack aircraft often are either not supersonic or have lower maximum speed.


How does an engine failure affect the flight of an airplane? I'm not even close to an aviation enthusiast, but after watching some videos I found I have a deep misunderstanding on how airplanes work.

.

I've seen many cases where one of the engines fail and the plane has to fly on a single engine for a long time.

How doesn't the fact that the forces are now uneven drive the airplane to a side drift? (I'm sure this is all wrong, but I just don't understand how)

It does.  Asymmetric thrust will in fact force the airplane into a turn unless the pilot counteracts this by using rudder and aileron to command an equal turn force in the other direction.  Typically both opposing rudder, and banking away from the dead engine will be used to result in straight (although uncoordinated) flight.