I hold both a Sport Pilot License and a Student Pilot certificate. Can I do my BFR in a C-172? FAR § 61.56.(c).(1) states that every two years I must have

  Accomplished a flight review given in an aircraft for which that pilot is rated by an authorized instructor.

The answer to my question hinges on the exact meaning of the word "rated". If I've been signed off to solo in a C-172, am I "rated" for that aircraft as far as this regulation is concerned?

Nope, sorry! If you need a flight review, use an LSA you have been endorsed for.

§61.56(c)(1) states that a flight review must be:

  Accomplished [...] in an aircraft for which that pilot is rated

According to the AOPA (note: this article is specifically targeted at non-Sport pilots):

  Rated is interpreted as category and class [emphasis mine]

And in another article, the AOPA continues:

  Sport pilot certificates will be issued without category/class designation

...and just for the final nail in the coffin, here's the FAA itself (thanks, @Pondlife!), in AC 61-98B:

  A pilot who holds only a sport pilot certificate may only take a flight review in a light sport aircraft for which he or she holds an operational privilege. For example, a sport pilot who holds airplane privileges could not take the flight review in a Cessna 172 since that airplane is not a light sport airplane and he or she does not hold operating privileges for that airplane.

Long story short, this all means that no, a Sport Pilot cannot perform a flight review in a non-LSA type. Because you require specific logbook endorsements in make/model for category/class/speed (an LSA like a Sting S3 vs Airplane Single-Engine Land), you are not rated to fly a Cessna 172, for example. Your solo endorsement isn't a rating, as it isn't part of a certificate - it's an endorsement.

Once you become a Private Pilot, you'll be able to do a flight review in almost any ASEL type, including all LSAs because you're suddenly rated for the Airplane category and Single Engine Land class, with no light-sport-only limitation.

As far as I can tell, your student pilot certificate is actually invalid. It's been superseded by your Sport Pilot certificate and you are now adding privileges to that certificate. As such, it doesn't really matter that you've been endorsed for solo in a 172; you aren't rated to fly one in the same way you are for an LSA.


What is this high wing twin airplane? It sits in a very large backyard in Lancaster, California.

Occulted top cockpit windows are quite misleading in identifying this one.

It is a Percival P-50 Prince 2

(source)

It may very well be this exact one:

(source)

Description in source image tells: N206UP, 1953 Percival P-50 Prince 2, C/N: P50/10, Standing in a private garden near Antelope Acres CA

Also provides a googlemaps link


Can a harbor freight predator 212 cc engine be enough for an ultralight Hi I am planing on building a budget ultralight and I was wondering if a 6.5 hp 212 cc predator motor will be enough and if so what size prop should I use.

A little background, it is going to be a wood and foam plane with fiberglass covering I am going to have a few bits and pieces of aluminum for strength. I don’t have a plan yet because I am going to plan it around the engine. I am shooting for 160 pounds dry. Thank you in advance.

6.5 hp is enough to get a person off the ground - but it would require an extremely aerodynamically- and structurally- efficient airframe to do so. A first-time builder without experience or training is not going to build such an airframe on the cheap from wood and foam and fiberglass with "bits and pieces of aluminum for strength". Either the wings will break and you'll kill yourself, or more likely it just won't get airborne.

You should scrap this idea and instead find a good set of plans and follow them exactly.


Does the movement of the magnetic poles affect aviation? Recently I read that Earth's magnetic pole moves quite significantly, several kilometers. Do these changes affect aviation, i.e. for pilots landing their airplanes?

I don't think magnetic shifting affects the pilots directly, but it does force airports to re-number their runways because of the fact that runways derive their numbers from their magnetic headings.

Other than that, I don't know of any direct effect this would have on the landing itself, as approaches rely on the ILS's radio signals or direct visual contact with the runway.


In a constant speed propeller, why does the RPM drop with a prop pitch increase? When a constant speed propeller changes its pitch from low to high, RPM would decrease.

Why is that the case?

Wouldn't the RPM increase when we increase the blade angle since there's less drag and the blades are more aligned to the relative wind, compared to when it's in a low pitch angle? Also, does higher blade pitch allow us to fly any faster?

The propeller blades indeed have least resistance when aligned with the inflowing airstream, however the inflowing airstream is not the free stream at infinity, but the vector sum of free stream velocity $V$ and rotational velocity of the propeller blade $\omega \cdot r$.

In the picture the local Angle of Attack is indicated as $\alpha$. Increasing blade pitch results in increasing $\alpha$, which means more air accelerated backwards: more thrust delivered, and more torque required.


Can civilians fly military aircraft? I saw a few videos of the Sukhoi Su-35 doing some amazing aerobatics and I was wondering if a civilian could ever fly one - either for aerobatics or just fly it as their personal jet.

Obviously assume adequate training, fitness, budget, time etc. I assume you'll have to start on a jet trainer first, after you had already flown other smaller aircraft - but this is outside the scope of my question.

There is a question that suggests civilians can buy military aircraft, but it doesn't explicitly say whether they can actually fly them. One comment seems to suggest they can't, although it's not very clear.

I'm not sure if you're asking about flying such an aircraft (e.g. renting one) or owning one. But either way the answer is yes.

I've flown a Hawker Hunter at a (now-defunct) location in Cape Town on a mixed low-level/acrobatic flight along the coast. There were no restrictions on who could fly in the aircraft apart from the obvious ones (no kids; must have reasonable height/weight and general fitness) but they didn't let non-pilots take the controls. We did some aerobatics (up to 5G, from memory) and I had the controls in cruise flight for about 10 minutes. There was absolutely nothing that a civilian couldn't learn: it's 'just' another aircraft.

As for owning one, it's not uncommon at all. Privately owned ex-military aircraft are often referred to as "warbirds" and in the US there's even an EAA organization for owners. The aircraft are usually considered experimental (or the local equivalent) for the purposes of regulation and airworthiness.

The barriers to owning these aircraft are (as always) money and training. Buying and maintaining them is very expensive because there are so few parts or mechanics available, and insuring them is (almost) impossible so most owners have to self-insure. The operating costs are also usually high, especially if the aircraft systems need 'exotic' fuels, gases, lubricants or other consumables. You may need to include explosives on the list, in the case of ejection seats.

Training is a similar issue because so few people can instruct you in how to fly a military aircraft, but obviously this isn't a total barrier and I assume that if you're involved in that part of the flying community then you'll find the contacts you need.

So in general, if you can buy a military aircraft legally in your country, if you have enough money for operations and maintenance, if you can find someone to train you, and if you can comply with your local regulations on non-type (experimental) aircraft then you can absolutely do it. But for most people that's a lot of 'ifs' :-)


Why might this trans-pacific flight not follow a more direct route? I notice that this flight from DFW to PVG has a path that’s not a single arc of a great circle. Rather, it looks like it flies to some city in California and then takes a direct route for the remainder.

Why might it do that, instead of following a more direct route, such as a great circle route?  It didn’t stop along the way, so why would it need to overfly an intermediate location that’s not on the direct route?

(flightaware.com) American Airlines 127 Thursday 04-May-2017

Compared to great circle route:

(gcmap.com)

Looks like they were avoiding a storm system from Oregon north into Canada.


How do FAR 23 takeoff requirements compare to FAR 25 requirements? What types of factors come into account when planning takeoff performance for dual engine aircraft under FAR 23, compared to the aircraft with certified takeoff distances under FAR 25

Obviously, the margin for light aircraft would be less, but does this difference make a significant change in the required (legal) distance or is it less that it seems?

The single biggest difference is that FAR 25 has rules that pertain to wet runways. Aside from that, FAR 25.113(a) uses the greater of two tests to determine accelerate-stop distance:

(1) Accelerate to $V_{EF}$, then reject the takeoff
(2) Accelerate to the highest speed required for takeoff (somewhat unclear?), then reject the takeoff

...while 23.55(a) is more or less equivalent to 25.113(a)(1).

Comparing the three methods, the rules are mostly comparable. The only major difference is that under Part 25 "a distance equivalent to 2 seconds at the $V_1$ for takeoff from a dry runway" (25.113a.1.iv and 25.113a.2.iii) must be added to the other factors.

Because aircraft certified under Part 25 must use the greater of two different tests and add a distance equivalent to 2 seconds at $V_1$, accelerate-stop distances will likely be greater than for Part 23-certified designs that are otherwise similar.

For reference:

FAR 23.55(a)
FAR 25.113(a)


Are cargo and passenger flights flown differently? Are aircraft flown differently because boxes don't complain about more abrupt changes in direction, speed, altitude, etc where passengers might. i.e. if the cargo is incapable of loading itself, is it subjected to a more aggressive flight regimen than if the cargo is self-loading and potentially complaint-filing.

I understand that Boeing, Airbus and other manufacturers produce essentially identical airframes in both passenger and cargo configurations, so they would have essentially identical flight envelopes, I just wonder if cargo flights are taken closer to the extremes.

Yes, cargo and passenger aircraft of the same basic model are sometimes flown differently when there is no live cargo. A friend of mine who flies cargo put it almost exactly as you did in your question when you say boxes cannot complain, so he sometimes hand flies the aircraft when passenger pilots would be required to use autopilot. Cargo pilots don't have to worry about tender stomachs in the back, so steeper climbs and descents and tighter turns are acceptable as long as the aircraft remains well within the flight envelope.


What do left handed F-16 pilots do about the right side stick? I was just watching a video about the Thunderbirds and Blue Angels doing their city fly overs and realized that the F-16 has a right hand side stick, which begs the question "what do left handed F-16 pilots do about it?" Adapt? Not get selected for that aircraft? These and other dumb questions for you

It does not truly matter what hand the “stick” is in. It matters how you were trained. It matters to what you have become accustomed.

Case in point...
In general, the pilot in command of a side-by-side pilot aircraft sits in the left seat. This is the seat in which most people begin their initial pilot training. You will typically control the control yoke with your left hand while manipulating the throttle, mixture, propeller control, radios and avionics with your right hand. When you advance to being a Certificated Flight Instructor, you will move to the right seat. In the right seat, you will you will control the control yoke with your right hand while your left hand does everything else. If you go on to become a captain in an airline, you will move back to the left seat.

If the same pilot starts training in a helicopter, the pilot in command seat is typically on the right side. You would reverse again which hand controls what.

Your training for the particular aircraft and position you fill will dictate how you operate. Not with which hand you are more dominant. Both right-handed and left-handed pilots fly their respective aircraft the same way. They train for it.


How do canard flaps work? Before examining this XB-70 picture

I thought that all canard were one single flight control surface (as seen on many fighters such as the Eurofighter Typhoon), and that there functionning were comparable to stabilators.

But the XB-70 exhibit something that looks like large flaps at the trailing edge of its canard. Apparently, it is not the only airplane with this feature (e.g. the Saab 37 Viggen is also equipped with similar canard).

What is this canard flap? How does it work? Is there any pro/cons of this configuration compared to a all moving canard (I don't know if this can be called stabilator as this is not located on the tail)?

The canard flap is like any other control surface in the trailing edge of a canard. The canard flaps are there mainly for trimming the aircraft.

At transonic speeds, the center of pressure of the aircraft moves rearward, resulting in instability. This could be countered by trimming with the elevons; however, this increases the angle of attack (the elevon deflection in XB70 was between $0^{\circ}$ and $10^{\circ}$)- resulting in increased drag. The small flaps in the XB70's canard was used to counter the movement of center of pressure without changing the main wings AoA, which eliminated the speed and range penalty due to increased drag.

Another advantage is during the landing. The landing attitude of delta aircraft is usually steep and fast compared to other aircraft. The deflection of canard flaps in the XB-70 pitched the nose up, enabling the elevons to be operated as trailing edge flaps- this helped the to keep the landing attitude shallower and speed, lower.

Actually, in case of XB-70, the canard was exclusively a trimming device- the longitudinal control was provided solely by the elevons.

During landing, the use of flaps cause a negative pitching moment- In aircraft with horizontal stabilizers, flap deployment may increase the downward airflow on the horizontal tail, producing a pitch up moment. in case of aircraft without stabilizers, it is not possible. In order to trim the aircraft, the canard flaps in Saab Viggen were deployed; in case of Beechcraft starship, a variable sweep canard was used for the same purpose.

The main disadvantage of having flaps in canard was the increased complexity. The canard can in itself be used to provide the required trim; the flaps are used only when the canard is highly loaded and may not have sufficient spare lifting capacity to accommodate large movements of the centre of pressure or of the centre of gravity. Note that in case of XB-70, initially, the canard was fixed and the flaps were adjustable; later the canards were made trimmable with the flap deflection set at two positions- $0^{\circ}$ and $20^{\circ}$.

References: WarbirdTech: North American XB-70A Valkyrie by Dennis R. Jenkins and Tony Landis; Summary of Preliminary Data Derived from the XB-70 Airplanes by William H. Andrews, NASA Technical Memorandum TM X-1240


Was there ever an accident from in-flight smoking? In the 80s and 90s, regulation increased to prohibit smoking in passenger planes. Was smoking ever identified as the cause for serious accident in flight (for example the cabin caught fire as a result of a stray cigarette on the carpeting or seats)?

24 December 1982; CAAC Ilyushin 18B; Canton (Guangzhou), China: The aircraft was on a scheduled domestic flight when an onboard fire broke out as a result of a carelessly discarded cigarette. The aircraft landed and the passengers and crew evacuated, but 25 of the 50 passengers were killed. All 11 crew members survived. source


Is a flying wing optimal for high altitude craft? One of the biggest problems with flying wings is their sheer thickness, which creates excessive drag.
However, since high altitude craft need bigger (and thus thicker) wings anyway, and since weight us a bigger issue with these larger wings, and is addressed with the flying wing, would a flying wing not be the best option for accommodating the required payload volume for minimum surface area and weight extreme altitudes?
Yet high altitude aircraft up till now have used the tube and wing configuration. Why?

For maximum altitude, the primary distinction to be made is whether the airplane flies at subsonic or supersonic speed.
Subsonic speed
There are several factors for maximum altitude, but the maximum altitude of specially developed high altitude airplanes is determined by the coffin corner which in turn depends on the product of lift coefficient and Mach number squared. With a given $c_L\cdot M^2$ of about 0.4, which is as good as it gets, now altitude only depends on wing loading which has to be as low as possible for the best altitude. Note that the best subsonic performances were reached with electric propulsion because combustion engines will not work anymore with the low partial pressure of oxygen at altitude.
A high $c_L\cdot M^2$ can best be achieved with generous rear loading on the airfoil. This will upset the longitudinal stability of flying wings - using rear loading at the center will require generous downforce at the tips, and it is the overall $c_L$ that has to be counted for $c_L\cdot M^2$. Reflex airfoils are poor in that respect and do not come close to the value of 0.4 for $c_L\cdot M^2$ which is easily possible with rear loading.
That the altitude record holder is a flying wing shows that low wing loading is the most important feature for high altitude, but the Helios had neither crew nor a serious payload, so its practical usability was very limited. Add to that the fact that the structure was too fragile to survive even moderate gusts and it becomes obvious that a super lightweight span loader is not a practical design.
Supersonic speed
High means fast, and fast means draggy. As can be seen from the envelope of successful designs, they need to fly in a small range of dynamic pressure and have to fly faster to climb higher. Now thermal peak loads will limit what is possible and electric propulsion is out of the question. As a rough estimate for the possible drag at supersonic speed, Dietrich Küchemann once gave this approximation:
$$\left(\frac{L}{D}\right)_{max} = \frac{4\cdot(M+3)}{M}$$ which can be improved for waverider configurations to:
$$\left(\frac{L}{D}\right)_{max} = \frac{6\cdot(M+2)}{M}$$
Regardless which version you choose, both show that L/D suffers with increased flight Mach number $M$. At Mach 5 your best hope for L/D would be 8, only bit more than what Concorde reached at Mach 2. Partial oxygen pressure is of no concern since recompression at the intake will raise the pressure sufficiently - now flow speed and gas temperature in the combustion chamber will set limits to what is possible. The high level of thrust also means that the engine will determine the configuration. Sustained flight at more than Mach 5 has so far only been possible with rockets.
This means your optimum configuration is a slender Delta wing with a lot of internal volume for the hydrogen fuel required by the scramjet or it is a cylindrical pressure vessel with fins.


Do airline SOP normally recommend an in-flight engine restart in the case of an unexplained shutdown? You're flying along at cruise in say a 737 or similar twin-engined yet. Suddenly, one of your engines shut down for no apparent reason. (or no abnormal indications such as low oil or similar)

Do you:

Attempt a restart and either divert or continue?
Divert and leave it off for an emergency landing?

Your question mentions the 737 or similar. If you want answers limited to 2-engine jets, let me know and I'll remove this answer as it is for the 747-100 or -200.

Whether to restart or not depends on the nature of the failure. If there appears to be no problem to do otherwise, a restart would be in order. The checklist for an inflight start from the last airline I flew for (now out of business) is below. The code to the right of each action is who performs it: C - captain, FE - flight engineer, All - all 3 crew members.

Thurst Lever ............................... CLOSE        C

Start Lever ................................ CUTOFF       C

Fuel Pressure .............................. AVAILABLE    FE

Bleed Air Valve ............................ OPEN         FE

Engine Ignition (Sys 1 and Sys 2)

     Above 250 KTS ......................... FLT START    FE

     250 KTS and Below ..................... GND START    FE

Start Lever ................................ RICH/IDLE    C

Engine Instruments ......................... STABILIZED   ALL

Start Lever ................................ IDLE         C

Engine Ignition ............................ AS REQUIRED  FE

Electrical Power ........................... RESTORE      FE

The most likely cause for a Pratt & Whitney JT-9 engine to quit is poor technique on the part of the pilot. If you're at altitude and starting the initial descent, you should put the nose down before bringing the thrust levers back. Also, don't slam them back, take a few seconds to do it, especially if you're above FL370.

It's worth noting that on the 747, the loss of an engine (no restart) enroute is not considered a serious emergency. At the two 747 carriers I flew for, it was the captain's discretion as to whether to divert or to continue on.

Also, it's not always the case of either the engine works at the power of the other engines or it doesn't. There are situations where the engine might be available, but with partial power. As I remember there were at least two such cases, one of which was high oil temperature. Basically the work-around was to run the engine at that power setting that would keep the oil temp below the maximum.


Why shouldn’t the A330/40’s speedbrakes be used in alternate law? On page 30 of the ATSB report into the QF72 accident (page 50 of the PDF file of the report), in a table describing the actions required of the flightcrew in response to some of the ECAM messages displayed during the flight, there is the following entry:

ECAM message [...] Required actions
[...]
F/CTL ALTN LAW (PROT LOST) [...] Do not use speed brake [...] Maximum speed limited to 330 kts / Mach 0.82

[ATSB Transport Safety Report AO-2008-070, page 30 (PDF page 50), Table 6.  Table headings bolded in original; all other bolding is my own.]
Why aren’t the A330/40’s speedbrakes (the term used for the aircraft’s flight spoilers, when deployed symmetrically to increase the aircraft’s drag and reduce its lift) supposed to be used when in alternate law?

The table in the report omits a condition. Here is the ECAM message in full:

The limitation applies when the aircraft is in emergency electrical configuration (run by the ram air turbine), which is one way to have the flight laws degraded.
The manual does not give a direct reason (not unheard of), but in fact there's more than one reason.

► As a quick summary, you lose 2/3 of the spoilers and the outer ailerons, and if more unlucky, you lose 5/6 of the spoilers.
If you happen to use the now-not-very-helpful spoilers, and you lose more hydraulic pressure, they'll get stuck in the up position (adding drag and degrading roll). So, DO NOT USE makes sense.

The how:

In emer elec config, the plane loses 3 of the 5 flight control computers; what remains are P1 and S1 (refer to diagram above).

The outer ailerons go into an unpowered state to conserve hydraulic fluid/pressure – the right aileron upfloats* like on the A320 (no P3 and S2).

If the planes loses G or Y hydraulic pressure, the plane is left with one panel on each wing, which is likely to be needed for roll control at slower speeds (the outer ailerons are already out).

The references (click to view):

All images are from the A340 FCOM, and color highlights are mine. Do not use for flight.
A330 vs A340
Thanks to @JZYL, note that there are some differences between the A330 and A340, while the A340 would announce MOST SPOILERS being INOP, the A330 would announce HALF SPOILERS (an extra computer remains powered). The same rationale given should apply though.
* This is also confirmed from this FCTM (smartcockpit.com) of an airline with both the A330 and A340 in its fleet (see PDF page 207):

(...) The AP will disengage when the failure occurs but AP 1 can be reengaged on the A333 if the EMER GEN is powered by an EDP. As there is no AP available in this configuration in the A340, the Captain must take control and fly the aircraft manually. The A340 aircraft is out of trim in roll due to right outboard aileron upfloat, caused by no power being available to Prim 3 or Sec 2, and neither pitch trim or rudder trim is available. (...)

Note: I haven't found a reason for the different architecture, but ETOPS is a possibility.


Can an airport without an FAA controlled tower have their own tower and controllers? Can an airport not eligible for an FAA tower and controllers choose to fund their own air traffic control tower? Can that airport require pilots to taxi, approach, land, and take off according to their tower's instructions?

If so, are there requirements for the controllers in terms of certification, or can they hire anyone they deem suitable for their airport? Do they have to coordinate with the FAA or air traffic control system in some special way?

Yes, in fact there are a number of Non-Federal Control Towers (NFCT) in the United States.  These are NOT the same as Federal Contract Towers (FCT), which are funded by the FAA and operated by contract personnel.

NFCTs, on the other hand, are usually funded by the local airport authority.  Some examples (not authoritative or all inclusive): Mojave (MHV), Laughlin/Bullhead City (IFP), and Merritt-Titusville (COI).

Unfortunately, there isn't a consolidated list of all NFCTs.  Rather, they are tracked by their respective FAA region.  Here are the Southern and Western-Pacific Hub Organization Orders that list their respective NFCTs (not sure if they're current).

Operation of NFCTs is covered by AC 90-93b.


What rotors would be best for atmospheric reentry? What rotor blade set up would be the best for entering Earth atmosphere or to shed speed before landing in place of a parachute?

I understand that the longer blades are more efficient, but are not as strong.
The link below explains how this might be used.

https://space.stackexchange.com/questions/35699/could-a-rotary-rocket-charge-a-super-capacitor-while-descending-on-mars's

https://commons.erau.edu/cgi/viewcontent.cgi?article=1283&context=discovery-day

Related: Would an aircraft with contra-rotating propellers longer than the plane's wingspan be able to fly?

You couldn't do it to control reentry, but you certainly could do it for a vertical landing system that might be a bit less technically demanding than a rocket that can descend under control with its engine running as SpaceX does.

You are limited by the mach# of the tips of the rotor, which have to be subsonic while spinning.  You would want a rotor that can fold alongside the rocket and deploy and accelerate to operating RPM once it's approaching the surface, and reduce the descent rate to an acceptable level where the craft can land with its gear absorbing the landing shock in a zero forward airspeed autorotation.

This is not hard to do with a well designed gear and there are gyrocopters with gear that is designed to handle zero-forward speed autorotation landings (basically, they can cope with high descent rates by using long-stroke shock absorbers).

The rotor would simply be the simplest, lightest, cheapest system that you can come up with, that the landing gear can handle.  If you could do it with two blades you'd go with that, but maybe packaging would require more blades, and you'd have to find some sweet spot with the best overall landing performance between the rotor and landing gear, and your physical packaging limitations.


What's the pilot's typical reaction time to co-pilot's callouts? How long does it take on average before a pilot initiates an action in reaction to a co-pilot's callout? Are there any research data on this subject?

I'm asking this question in relation to the V1 speed, or more specifically to figure out whether it's a reasonable procedure to require pilots to continue takeoff (even) when an engine has failed one or two seconds prior to reaching the V1 speed, taking into account their reaction time.

The best research on this is done with real crews & expensive simulators, and I think their results are exactly the proposition you're looking at, namely that the callout "V1" needs to be said something like a second or two before the actual latest-point-of-first-action to reject the takeoff.

The reason that we can't just say, how long does it take me to respond to the other pilot's callout routinely is, it's a different world between the routine stuff and the abort decision close to V1.  As an example, if I'm flying an approach, I know when the callout 100 feet above minimums is coming.  If I'm not badly tunnel-vision on some isolated part of my scan (very, very rare when you're at that point in an approach... not impossible but quite rare), I can see the altimeter unwinding toward the minimums bug, and so when the other pilot makes the callout, I'm ready to reply "going outside."  And I know that a few moments after that, he's going to call out "minimums" and I have my next callout to make.  No surprises, and if you measured how promptly I respond to his callouts, you'll probably get results showing that I'm pretty prompt.

Compare that with the one takeoff in thousands where things are getting weird close to V1, and I'm actually processing the "is this actually worth stopping for now that we're high speed" decision. I've never had to do that in the actual aircraft, but talking to guys who have, there is some very real time compression -- events happen fast. On a normal takeoff, I'm almost always aware of exactly when the "V1" callout is coming.  But if it is "that dark & stormy night" and I'm trying to sort out the difference between fluxing indication, minor burp, or beginning of an engine failure, that will be the time when the "V1" call WILL catch me by surprise, and how quickly I react to it & remove my hand from the throttles may not correlate to how quickly I've taken it off during the last 999 takeoffs.

On a normal takeoff, my habit is a fairly spring-loaded motion where my hand comes up and away from the throttles immediately at the "V1" call, so that if we get the proverbial big bang, lotsa yaw, and the fire bell right after the callout, I'd be able to catch myself & not go reaching back toward the throttles to initiate an abort-after-V1.  So on those days, you might could get away with pushing the callout closer in time to the latest-first-action-to-stop point.  But not every day is going to be like that, so the Boeing procedures build in the greater level of reaction time.

Because taking the aircraft flying even when you had another second or two that you could have stopped it, is generally (looking at the historical track record of takeoffs rejected & takeoffs continued) less dangerous than stopping the aircraft a couple of seconds after you shouldn't have.

References:

Boeing Article
Boeing Slides - 2002 Presentation This has some good time numbers for you


Who first coined the phrase "aviate, navigate, communicate"? The phrase "aviate, navigate, communicate" describes the priorities of tasks for a pilot. It is applicable to a wide variety of situations, including military scenarios and emergencies.

Who first introduced this phrase, and when did it first appear in the aviation community?

I don't know the genesis of the phrase, but I heard several WWII era military pilots interleave it with stories of their sorties, and of the debriefs for those sorties.  Based upon that, I would say that the expression dates back to at least the early-1940's.


Which "pilotless aircraft" did the authors of the 1944 Chicago convention have in mind? The Convention on International Civil Aviation (a.k.a. the "Chicago convention"), includes right from its first version, signed in 1944, an article about "pilotless aircraft". The article in question reads:

Pilotless aircraft
Article 8
No aircraft capable of being flown without a pilot shall be flown
without a pilot over the territory of a contracting State without
special authorization by that State and in accordance with the terms
of such authorization. Each contracting State undertakes to insure
that the flight of such aircraft without a pilot in regions open to
civil aircraft shall be so controlled as to obviate danger to civil
aircraft.

The original text is available here.
I would guess that language like that (which it takes time and effort to produce) will not get included in an international treaty without a reason.
So the question is, which aircraft did the authors of article 8 have in mind in 1944?

Note that the article says that

  No aircraft capable of being flown without a pilot

At that point of time there were a number of radio controlled aircraft which could be flown without a pilot on board (for example, the RP series aircraft and OQ-2 Target drone, of which thousands were made). The authors of convention most probably had these in mind when they frame the article 8.

This ICAO document on Unmanned Aircraft Systems also points in the same direction:

  4.3  Article  8  details  conditions  for  operating  a  “pilotless”  aircraft  over  the  territory  of  a  contracting  State.  To  understand  he  implications  of  this  Article  and  its  inclusion  from  the  Paris  convention  of  1919  (Article  15)  into  the  Chicago  Convention  of  1944,  the  intent  of  the  drafters  must  be  considered.  Remote-control  and  uncontrolled  aircraft  were in existence at the time, operated by both civil and military entities. “[A]ircraft flown without a pilot” therefore refers to  the  situation  where  there  is  no  pilot  on  board  the  aircraft.  As  a  consequence,  any  RPA  is  a  “pilotless”  aircraft,  consistent with the intent of the drafters of Article 8.

(emphasis mine). So, the authors of the 1944 Chicago convention most probably had radio controlled aircraft in mind.


Do you have to update weight and balance charts after installing new avionics? The POH always has weight and balance charts. Let's say you install some new avionics, hence changing the weight of the aircraft. Do you need to update the POH binder with new weight & balance charts? What about take-off/landing distance information?

For the US under the FAA, Yes you do!

From the FAA WB handbook

  Changes of fixed equipment may have a major effect upon the weight of
  the aircraft. Many aircraft are overloaded by the installation of
  extra radios or instruments. Fortunately, the replacement of older,
  heavy electronic equipment with newer, lighter types results in a
  weight reduction. This weight change, however helpful, can cause the
  CG to shift, which must be computed and annotated in the weight and
  balance record.

For larger repairs.

  Repairs and alterations are the major sources of weight changes. It is
  the responsibility of the FAA-certificate mechanic or repairman making
  any repair or alteration to know the weight and location of a change,
  to compute the CG, record the new empty weight and EWCG in the
  aircraft weight and balance record, and update the equipment lists.

Generally this is done by the shop that installs them. If you as the owner/operator installs them (which you are permitted to do to some extent) you may need to have a new WB drafted up.

This is also checked at anual every year,

  The FAA-certificated mechanic or repairman conducting an annual or
  condition inspection must ensure the weight and balance data in the
  aircraft records is current and accurate. It is the responsibility of
  the PIC to use the most current weight and balance data when operating
  the aircraft.


Is there a rule of thumb for spacing between jet engines? While viewing this week's press release for the taxi test of the Stratolaunch I noticed how closely the engines seemed to be spaced. It would seem the ideal position would be near the fuselage to minimize asymmetric thrust.

The B-52 places engines directly next to each other, while the 747 spaces them far apart. Is there a rule of thumb for ideal engine spacing?

[This question deliberately excludes propeller aircraft due to the many mechanical and aerodynamic differences.]

The Stratolaunch engines are approximately one engine diameter apart and very close to the fuselage.

The 747 has much larger spacing between engines (~3 engine diameters) and further from the fuselage.

Engine spacing on the Antonov 225 compared to the 747 is much closer to fuselage but about the same spacing.

Placing the engines farther out is mainly done for bending relief in the wing. Given that the Stratolaunch needs to keep its center wing clear of fuselages and engine nacelles, the engines are out enough already. Moving them farther out would create more thrust asymmetry once one engine fails.

Airliners with a central fuselage are different. We have an answer here discussing optimum engine placement. Why they should not be combined in one nacelle is explained here.


How do pilots see at night if airplanes don't have front lights? How can pilots identify threats ahead of them if they don't have front lights like cars?

Short answer: they do have front lights!

Longer answer: There's lots of stuff for a ground vehicle (such as a car) to hit, because there's lots of stuff close to the ground.  There's not much in the air for an aircraft to hit, besides other aircraft.  Lights on an aircraft in flight are to help the airplane be seen, not to help the airplane see.

On landing, forward-pointed lights are nice to have, but since runways are illuminated, it's possible to land safely without them.  Airliners in particular will probably never be landing on a darkened runway and need to worry about hitting invisible terrain or obstacles ahead, because they're always either above the obstacles or they're on a known safe descent path.


Why isn't the application of "carb heat" in initial piston multi-engine failure emergency procedures? What is the rationale for not including the application of carb heat in the initial multi-engine airplane's engine failure procedure?

I've recently starting flying light multi-engine airplanes again and have been practicing the engine failure procedures.

I noticed in the POH of the aircraft I'm flying that it doesn't mention applying Carb Heat to the dead engine. So I looked at some other multi-engine POH emergency procedures and noticed that Carb Heat is mentioned sometimes, but in the trouble shooting checklist for restarting, after the initial procedure.

Shouldn't carb heat be applied as soon as possible, while manifold is still hot enough to heat the air to melt any potential carb ice?  Like immediately after pushing everything forward and getting gear and flaps up?

Alternatively, I can also see an argument that before you identify the dead engine, applying carb heat to both engines would decrease some precious power from the currently functioning engine. Are there other reasons for not using carb heat sooner?

Partly because carb heat is ineffective once the engine is no longer making power, but mostly because the initial engine out procedure isn't intended as remedial action to get the engine running again; the drill is to make sure the airplane is configured to be able to climb (somewhat) in the moments after the failure, so the priority is everything balls to the wall, gear and flaps, identify, confirm, feather with the aim of establishing a climb foremost.

In any case, if you applied carb heat to both engines as part of the drill, the dead engine would be getting probably insufficient heat anyway, and the live engine will enjoy a few percent power reduction from the application of heat.  On a piston twin like a Seminole or Duchess at gross on a hot day, that alone may be the difference between barely climbing or descending, so that the remaining engine takes you directly to the scene of the crash as the old joke goes.


Why is the Departure leg of the traffic pattern being mistaught as Upwind? I hear a LOT of newer pilots and CFI's erroneously referring to the Departure leg of the traffic pattern as the Upwind. Ref. A.I.M. Sec 4-3-2.  Actually had a Tower controller tell me "I'll call your turn from Upwind"  I was clearly on Departure...just left the runway on runway heading. I called back "1234x is on Departure, sir" No reaction. Thank you.

Your Question:

  Why is the Departure leg of the traffic pattern being mistaught as Upwind?

Probably because it is quite common to use the term "Upwind" when flying the "Departure Leg" because when doing so, you are flying "upwind."  If you look at the Pilot/Controller Glossary  in both the AIM and ATC Handbook (same P/C glossary), the term "Departure" leg is not even mentioned.  It only shows in the body of the AIM.

Here is what the Pilot/Controller Glossary defines for a "Traffic Pattern:"

(emphasis mine)

  TRAFFIC  PATTERN
  −
    The  traffic  flow  that  is
  prescribed
  for aircraft landing at, taxiing on, or taking
  off  from  an  airport.  The  components  of  a  typical
  traffic  pattern  are  upwind  leg,  crosswind  leg,
  downwind leg, base leg, and final approach.

I'm not suggesting that the segment in the pattern you are referring to is not the "Departure leg," just that it is quite common to refer to this segment of the pattern while you are flying it as "upwind" (without the use of the word "leg").  The actual "Upwind leg" (as I'm certain you know) in a traffic pattern is flown parallel to the runway on the opposite side of the "Downwind leg".


Single engine failure in a light twin after lift-off: what to do? In a previous question the case about if a turnback would be feasible, specifically for a single engine aircraft, has been analysed.

But given a twin-engine general aviation aircraft and a single engine failure immediately after lift-off, considering that my Pilot handbook says:

  A continued take-off is not recommended if the steady rate of climb according to "Section XX" is less than Y%.

Considering the quite dangerous setting, I would say that is quite impractical to go and check that table in such a situation.

What kind of indicators might I look for to check if it safe to continue? Should I learn by heart such table? (I am not sure this is practical either, is a quite complex table)

In case I am unsure what to do, apart from trying to climb for a while then turn around or immediately try land in front of me (granted that there is enough space), are there, generally speaking, other options?

In the accepted answer of the listed question is said that

  It's not reasonable to try it [a turnaround] without knowing what altitude is needed for it at current conditions.

is it possible to estimate this quickly inside the cockpit?

What you really should learn by heart is the flight speed for best climb with one engine inoperative. Try to trim that immediately and you will win more time to make a decision. The rest is really depending on circumstances: Is there a landing opportunity ahead? Are you high enough to do a 180 and land on the same runway in opposite direction? Or are you high enough (and the aircraft does not lose altitude) that you can fly a pattern and land normally?

Testing the aircraft at altitude with one engine throttled is highly recommended, but be aware that the remaining thrust / drag of the throttled engine might be different from that of the stopped engine.


Can you obtain a pilot license with impaired vision / being blind in one eye? A friend of mine is blind in one eye and has normal vision in the other eye.  Would this prevent him from getting a Private Pilots License in the US?

It's possible to get a special issuance medical certificate in this case:

  An applicant will be considered monocular when there is only one eye
  or when the best corrected distant visual acuity in the poorer eye is
  no better than 20/200. An individual with one eye, or effective visual
  acuity equivalent to monocular, may be considered for medical
  certification, any class, through the special issuance section of part
  67 (14 CFR 67.401).


How do runway declared distances affect my takeoff distance? See these questions.

What is balanced field length?

What are runway declared distances?

My multi-engine jet airplane uses a balanced field length concept.  Most airports served by airliners have declared distances.

Obviously, my takeoff distance can't be longer than the runway length.  Does it have to be lower than all the declared distances?  TODA?  TORA?  ASDA?  LDA?

Actually, the take off distance given in runways will be greater than the runway distance as it will include the distance to overcome a predetermined obstacle.

Source: tc.gc.ca

The balanced field length is dependent on the aircraft configuration among other things and is usually available in AFM. The airfield lengths, on the other hand are made available so that operators can decide which aircraft to operate based on the runway lengths available.

In general, the ASDA should give you the available distance for taking off as it gives the required field length available in case you decide to abort the takeoff for whatever the reasons.


What is a hypernym for the ascending and descending legs of a flight? If an airline flight is everything that happens in between your starting and ending gates. What is the generic term for each time the plane ascends or descends during an air route? In layman terms, what terminology would define the four '_____?' equally as four separate things.

If the image below indicates the proper terminology for a flight. What is the hypernym for phase 3/4 and phase 6/7 of the air route?

Since a hyperonym can be a word or phrase, I'd go for a non-cruise airborne segment. Or N-CAS, as it'll be known from this moment in history.

The ICAO Common Taxonomy Team (pdf) doesn't have a term for it though.

From that document you can call 4, 5, and 6 (from your diagram) just en-route. And I don't see harm in expanding that term to include 3 and 7 as well (for the purposes of the question).

Also during cruise, some planes continue to climb in steps, it's called a step-climb. In that case you end up with multiple climb and cruise phases.

Which makes me think of stepping.

Officially there's no answer to your question, "en-route" fits in fine and is official, and "stepping" (up or down) would exclude the cruise as you requested, it works from a technical (albeit very broad) standpoint. But it can't be used officially or otherwise if you ask me.


Why is the landing gear lever not set to OFF on the ground? Several older airliners (e.g. Airbus A300, Boeing 737 until the NG series, Boeing 747 until the -400 series) have landing gear levers with three positions: UP, OFF and DOWN. OFF (or NEUTRAL for Airbus) means the hydraulic pressure is removed from the system because the gear is held in place mechanically. See also Why does the landing gear control have 3 positions (up/down/off) on Boeing 737-800?
The gear lever is typically set to the OFF position after the gear is retracted during the takeoff and the system therefore remains unpressurized during the flight:

Pilot Monitoring After flap retraction is complete:
[...]

Set the landing gear lever to OFF after landing gear retraction is complete.

(Boeing 737 NG FCOMv1 NP.21.46 - Normal Procedures - Amplified Procedures)
The gear is then lowered by selecting DOWN before landing, but it is not selected back to OFF after the landing gear is extended. I can understand why this would not be done during the landing phase (redundancy by keeping the gear pressurized down, reduced crew workload during highly critical phase of flight), but why is the lever not selected back to to OFF after landing?
Every procedure I can find lists the gear lever as DOWN on the ground:

Landing Gear Lever:

Check the L/G lever DOWN and the EMRG retract pb protected.

(Airbus A300 FCOM - Cockpit Safety Inspection)

LANDING GEAR lever .....................................................................DN
Verify that the green landing gear indicator lights are illuminated.
Verify that the red landing gear indicator lights are extinguished.

(Boeing 737 NG FCOMv1 SP.6.1 - Supplementary Procedures - Electrical Power Up)
Hydraulic pressure is not required to keep the gear down:

Landing Gear Extension
When the LANDING GEAR lever is moved to DN, hydraulic system A pressure
is used to release the uplocks. The landing gear extends by hydraulic pressure,
gravity and air loads. Overcenter mechanical and hydraulic locks hold the gear at
full extension. The nose wheel doors remain open when the gear is down.

(Boeing 737 NG FCOMv2 14.20.2 - Landing Gear - System Description, emphasis mine)
And furthermore, hydraulic pressure is lost anyway once the engines (and electrically powered hydraulic pumps) are switched off on the ground. So why would you want to keep the gear pressurized down on the ground until shutdown and again during startup?

Because there's no advantage to doing so (since the pumps will soon be off anyway, as the question notes), and this would create the risk that the pilot may overshoot the Off position to the Up position, which could, on a bad day, lead to an inadvertent gear retraction and major damage. The over-center locks are good, but do you really want to bet big bucks that the combination of 3,000 psi + a bad bump in the pavement will never produce an illustration of Murphy's Law?
Okay, there is one other safety to prevent overshooting, but that solenoid can fail, and if it does, watch out! There is simply zero need for this.
Also, depending on the plumbing, you might remove hydraulic pressure from the nosewheel steering by doing this (though I'd have to check the diagram to be sure).


How is a stolen aircraft returned to its owner? Once the authorities figure out where a stolen GA aircraft is, do they get the owner to come take it back? do they fly it back to its home airport? How exactly does the owner get his hands back on it?

If the owner retains ownership (rather than an insurance company who paid out a claim on the loss), it's up to the owner. The owner can either go pick it up if it is airworthy, or arrange for someone to ferry it back to the owner's home airport.


Temperature sensor are needed to compute True Airspeed for low speed aircrafts? I know standard air data computer can produce true air speed with total air pressure, static air pressure, and total air temperature. But for a low speed aircraft <100 knots, do I need to install a total air temperature sensor or other temperature sensor to get the true air speed computed? Or air temperature is not needed for low speed aircrafts and the air data computer can produce the true airspeed based on the calibrated air speed?

A good chunk of aircraft operating in the <100Kt range generally don't have Air Data Computers although glass cockpits are becoming more and more common in general aviation aircraft. For good old steam gauges a sliding temperature compensation scale is built right into the Air Speed Indicator, for more info on that see this question or this video. OAT is determined generally by a thermometer installed on the windscreen or in the side window.

If your aircraft is equipped with with a capable glass cockpit you may be able to get TAS from the system

  The Airspeed Indicator displays airspeed on a rolling number gauge
  using a moving tape. The true airspeed (TAS) is displayed in knots
  below the Airspeed Indicator.

The G1000 has an OAT gauge as part of the install.

  The Outside Air Temperature (OAT) and the deviation from International
  Standard Atmosphere (ISA) temperature are displayed in degrees Celsius
  (°C) by default in the lower left of the PFD under normal display
  conditions, or below the groundspeed in reversionary mode.


Is the Tower (Local) Controller responsible for "separating" VFR traffic in the pattern in the U.S. in Class D airspace? For example, in U.S. Class D airspace, if an inbound aircraft operating VFR is instructed by the Control Tower to "enter left downwind for runway 18, report entering downwind,"  is the controller  responsible for providing specific separation between that aircraft and other VFR traffic in the pattern (not on the runway or taxiway)?

If the controller instructs an aircraft on downwind to "turn base leg now, (VFR) traffic is on a 4 mile final on a straight in." Is the controller now responsible for the separation?

I realize these are two questions, but they are related.

Separation requirements depend on the class of airspace, per ICAO Annex 11.

Class D: VFR aircraft are not separated from any other aircraft. ATC only provides traffic information about VFR aircraft.

Note the separation can be done visually. Considering the size of the typical class D airspace, this is the usual method for multiple VFR aircraft in the area.

Once the aircraft get to the runway, the ATC regulation JO 7110.65 3−10−3 states that ATC is responsible for making sure an arriving aircraft doesn't cross the threshold before an aircraft ahead of it on the same runway is either landed and clear of the runway (or a certain distance past the threshold), or has departed and crossed the opposite end of the runway.

Also per 7110.65 2-1-1:

  The primary purpose of the ATC system is to prevent a collision
   involving aircraft operating in the system.

So while there may be no hard requirements for ATC to separate VFR aircraft, they will do their best to make sure that the VFR aircraft have the best chance of seeing and avoiding each other.


Why is the A400M APU on the side of the fuselage instead of the back? As you can see in this picture the APU of the A400M is on the side under the right wing, including the RAM-Air-Turbine.

Why is the A400M APU on the side of the fuselage instead of the back?
Why is the RAM-Air-Turbine not on the bottom of the fuselage?

The A400M is designed to operate from unpaved surfaces.

With the RAT on top, this avoids FOD issues, and provides ground clearance.

For the APU, it's space and proximity. You've got the wing box above the fuselage, plenty of space to add things there. Also easier maintenance access. Proximity as in less wiring and tubing to run inside the airframe, saves on weight and complexity. And again FOD. The inlet would be away from the debris and dust the wheels kick up.

Source: gizmodo.com


Gas Venting Stations: What's The Big Deal? On sectional charts you can see that, through various restrictions, regulators encourage pilots to avoid flying too close to Gas Venting Stations. These seem to be places where natural gas may occasionally be vented into the air (for example from pipelines). I have been unable to determine if the gas is preignited.

Is the principal risk from gas discharge that's being mitigated here:

aerodynamic
explosive/thermal
respiratory
a combination of the above?

Have incidents occurred relating to these risks?

You can find some talk of the risks online but it seems mainly to be in the form of "My mate told me...".

Gas venting stations sometimes release natural gas at extremely high pressures, so there is a risk of strong updrafts or turbulence. In any case if you fly directly over you may be going through a cloud of combustable gas which could possible ignite. It's a low risk, but given it's rarely a problem going around them it would be my advice to do so.

I've flown over one without realizing and it put me in a 1200ft climb, I had to cut throttle in a hurry and dive to stay out of the London TMA. After that I paid attention to them.


How many zig-zag patterns are there in a dog tooth leading edge? And also what is the difference between saw tooth and dog tooth leading edge?
Like is there any difference in the number of "zig-zag" patterns on the wing?

Both terms (“zig-zag” or “dogtooth”) designate the same leading edge aerodynamic design, and are used interchangeably. “Saw-tooth” is also used to indicate the same leading edge pattern, yet it is also used in naming a specific trailing edge design (a “saw-tooth” trailing edge; see this paper which explores this effect: Saw-tooth, or, Serrated trailing edge
The number of “cuts” (or, extrusions of the leading edge of a certain wing section compared to the leading edge towards the root of the wing) are a choice of design.
The “dogtooth” (or “sawtooth”, or “zig-zag”) at the leading edge acts in a way similar to a wing fence ), inducing an effect on the relative airflow which acts to prevent span-wise flow (and also adds energy to the air flowing over any control surface in the area, increasing its effectiveness.
As there are aircraft with numerous wing fences, so can the dog-tooth extrusion be multiplied on each wing, however, it is a question whether there were any planes out there with more than three such points of extrusion.
See this question for more detail: Hawker Hunter Dog-tooth wing - Aviation SE
Take a look at these pictures: notice the “dog-tooth” / “saw-tooth” leading edge and “saw-tooth” / “serrated” trailing edge.


How do fire crews handle hot brakes? Let suppose an emergency aircraft has made an overweight landing. The brakes are white hot, and the fire crews are requested to be on scene.

What can be done about the hot brakes? Can they just shoot water at the gear assembly? If flames are visible, would they shoot foam instead?

This related question asks how do fire crew inspect the brakes, but not what they do when the brakes are known to be very hot.

(Airbus) A320 landing gear approach paths.
It's important to approach the landing gear from the right angle, because an explosion could throw deadly debris at the firefighters.
Cooling
According to Airbus, water-mist is to be used to cool the brakes.
Water, CO2, or foam, are not to be used. All those cause sudden cooling that can lead to wheel cracks or rim burst.
Fire
If there is fire, then large amounts of water or water-mist is to be used. Foam is to be used if fuel tanks are at risk.
(YouTube) Fire crew attending to 1400°C brakes.

Not an emergency, but interesting:
(airliners.net)

Upon deplaning back in Pyongyang, we noticed the brakes of the main gear were being cooled down with water. Naturally, this led to a mass gathering downstairs, as everyone wanted to take a photo of this event. We learned that this is actually standard procedure, which seemed legit as I remembered seeing water on the apron after our [Ilyushin Il-62] flight as well.

Related: When the brakes are checked, what do the firemen actually do?


Does in-flight Wi-Fi require regulatory approval? Does any country have regulations that require a certificate or approval of the aircraft that use portable Wi-Fi in flight? Is there an FAA or EASA regulation or advisory, or an ICAO document or advisory?

The FAA touches upon it in this letter

  Current FAA regulations require an aircraft operator to determine that
  radio frequency interference from PEDs is not a flight safety risk
  before the operator authorizes them for use during certain phases of
  flight. Even PEDs that do not intentionally transmit signals can emit
  unintentional radio energy. This energy may affect aircraft safety
  because the signals can occur at the same frequencies used by the
  plane’s highly sensitive communications, navigation, flight control
  and electronic equipment. An airline must show it can prevent
  potential interference that could pose a safety hazard. The PED ARC
  report helps the FAA to guide airlines through determining that they
  can safely allow widespread use of PEDs.

The operator is responsible for determining that the unit does not create any interference they link off to this document which is pretty verbose and outlines a lot of the info you may be looking for on this front.

This document elaborates a bit more on the regulations

  Aircraft with an FAA-approved system— such as an Onboard Mobile
  Telecommunications System (OMTS), Wireless Fidelity (WiFi), airborne
  access systems (AASs), or Network Control Units (NCUs)—are considered
  PED-tolerant for PEDs used with the installed system. If an aircraft
  model has demonstrated tolerance for both transmitting and
  non-transmitting PEDs, the operator may allow PED use during all
  phases of flight on this aircraft model.

Aircraft need to be shown to be PED tolerant for Wifi units. You can find an AC covering whats involved in that here.


What features are cursor controlled on the A380 Navigation Display? I read that on the A380 and A350, certain features on the Navigation Display can be controlled via the Keyboard and Cursor Control Unit (KCCU). However, I did not find a full list of these features. I only found the On-Board Airport Navigation System (OANS) and Brake to Vacate (BTV) as examples.

Does it include, for example, selecting elements (waypoints, navaids) for the flightplan with the cursor?

This is what the KCCU looks like:

Source: A380-800 Flight Deck and Systems Briefing for Pilots

Each KCCU is connected to its FMS:

Source: A380-800 Flight Deck and Systems Briefing for Pilots

From the Airbus booklet cited above:

  The flight crew uses the KCCU to:
     • Navigate through the FMS pages on the MFD
     • Enter and modify data on the MFD
     • Perform some flight plan revisions on the lateral ND.

And:

  The KCCUs enable the flight crew to directly interact with the onside
  ND, MFD and the mailbox section of the SD.

The KCCU can be used, for instance:

  To select an airport
  To navigate throughout the Airport Moving Map (drag technique)
  To set some marks (flags and crosses) for drawing a path
  To activate the correct database.

(source: Getting to grip with surveillance

This figure shows what is reachable with the KCCU:

Source: A380-800 Flight Deck and Systems Briefing for Pilots

As there are two KCCU:

  Each KCCU displays a different cursor. If both cursors are displayed
  on the SD, only one can be active.

There is a functional redundancy between the keyboard and the cursor control unit.

The Onboard Airport Navigation System which displays a moving airport navigation map, is also accessible using the KCCU interactively.

You may also have a look at the book Introduction to Avionics Systems:

  The Multi-Function Display (MFD) displays textual data; over 50 FMS
  pages provide information on the flight plan, aircraft position and
  flight performance. The MFD is interactive; the flight crew can
  navigate through the pages and can consult, enter or modify the data
  via the Keyboard and Cursor Control Unit (KCCU).

  The Keyboard and
  Cursor Control Unit (KCCU) enables the flight crew to navigate through
  the FMS pages on the MFD and enter and modify data on the MFD, as
  mentioned above, and can also perform some flight plan revisions on
  the lateral Navigation Display (ND).


Why can't you ditch your aircraft in the sea? Disclosure: I'm just a random guy who knows nothing about aviation. :-)

I read:

  A voice in my earphones was shouting: “Ditch the plane! Ditch it in the ocean!”
      It must have come from the tanker skipper or one of the destroyer commanders down below, because every jet pilot knows you can’t ditch a jet and survive. The plane would hit the water at a very high a speed, flip over and sink like a stone and they usually explode on impact.

Okay, but the physics-y side of me wonders why you can't do the following:

Get ready to jump out (open windows, remove all attachments, etc.)
Glide down as close to the surface of the ocean as possible, maintaining some momentum
When you're as low as possible (but still high enough to allow this maneuver), suddenly pull up the nose as high as you can while keeping altitude constant as long as possible

I expect that, if done properly, this could nearly halt horizontal motion of the aircraft; when the momentum is finally lost, I expect the plane would suddenly "drop" in the water from a few feet above, after which you can (hopefully?) jump out of the cockpit immediately.

Now I'm not expecting a 100% survival rate here (I'd almost certainly die trying this), but it certainly seems to potentially beat jumping out of your plane at 15,000 feet and risk getting chopped up by the tail or having your parachute not open (and consequently breaking your spine, etc.).

Where am I going wrong with this? Why is ditching your aircraft in the ocean not an option?
(Does it e.g. depend on the type of the plane?)

The writer was dramatizing things a bit maybe, it's possible to ditch a jet fighter and survive, however your chances are much better ejecting.

Ditching is an option for any aircraft, with some airplanes ditching is the only option if there's a loss of power over water, for example commercial jets have no mode of egress other than the doors. I fly light single engine aircraft and the majority of the time I have no parachute, if my engine throws a rod over a big body of water that's where I'm going to go, and even if I had a chute I'd probably elect to ditch anyway. It's survivable, and many cases people do. The "Miracle on the Hudson" is a famous example, they even made a movie about it, but there are many others where a reasonable percentage of people on board survived.

You are proposing a low speed ditching in a fighter airplane, which has a number of drawbacks:

Ditching speed: You can't stop an aircraft by raising the nose higher because at some point you will stall the wings, and they will lose lift. A wing requires smooth airflow to create lift, if the airflow separates from the top surface of the wing it will stop flying, a condition known as a wing stall. In a jet that speed will likely be in excess of 130 knots (150 mph), and there's nothing you can do to slow it further than that. At that speed water cannot get out of the way fast enough and is very, very hard, not some sort of pillow which will cushion an impact
Slow speed controllability: Fighter jets are designed for high speed maneuverability, not low speed flight, fly too slow and you can lose directional stability and control
Loss of hydraulics: most fighters have assisted controls which require engine power for the pilot to operate easily, lose power and they lose effectiveness even with auxiliary power being generated
Unknown sea conditions: Sea conditions can have an enormous impact on ditching survivability, the successful ditchings I can think of were in relatively calm conditions where the pilot was able to make a good, even contact with the water. Dig a wing in and the drag will swing the airplane around, most likely breaking it up. It's very hard to gauge sea conditions from any sort of altitude; what looks calm from 5,000ft up could very well be heavy swells once you're close

So what you are suggesting is that a pilot skims the surface of possibly high seas, bleeding off speed in an airplane with progressively degraded control authority - which is also on fire. It's possible, but highly unlikely to work.

The most critical reason the pilot in the tale you linked to had to escape the aircraft was that a fire in the engine would melt the linkages for the rudder and elevator controls in the tail, or cause a catastrophic structural failure long before he could have ditched, causing a total loss of control. There's no chance that would have been survivable.


How should I build removable wings on a home build? In the future I would like to build a home built aircraft from scratch, but I would like the aircraft to be able to be hauled by trailer. I would like the wings to be removable but don’t have a definitive answer on how to go about building the wings and how the control cables would connect to the ailerons. I would also like to know how the detachable wings would be attached and kept to the main body of the aircraft securely without falling off. The wings are elliptical that come out straight for about six ribs, then angle up at about 15 degrees.

Planes on board of aircraft carriers have this: they need to fit all next together in a tight space, so they are made with foldable wings. This photo shows the folding mechanism:

Image source

Both sides of the split end in a full rib plate.
The two ends are connected via two large pins. The upper pin is the fold-up hinge, the lower pin is moved in-out via a hydraulic cylinder.
Aileron control is via a push-pull rod, with a connection bolt right at the wing hinge point, so that the wing part of the linkage can fold up/down.

The vertical black rod keeps the wing up. If one would like to remove the wing completely, only the upper wing pin and the aileron push-pull connection rod would need to be disconnected.


What are the advantages/disadvantages of diesel/Jet A-1 piston engine? Some GA aircraft, notably the DA40/DA42, are equipped with piston engines that use Jet A-1 and/or automotive-grade diesel instead of aviation gas (avgas). An example of such engine is the Austro Engine AE300:

What are the advantages/disadvantages of these engines and why are they not more common?

Advantages

Compression-ignition engines have higher compression ratio which leads to being more efficient. So the aircraft range improves and on longer flights payload capacity may improve as well. Fuel consumption is usually about 30% lower.
The higher efficiency combined with the fact that Jet A-1 fuel is cheaper mean they have lower operating cost. Especially since in Europe the leaded avgas is heavily taxed to discourage it's use for environmental concerns.
They should be a bit more reliable. A diesel engine needs high pressure fuel pump, but apparently there are less problems with those than there are with spark-plugs.
They are somewhat easier to operate, since they don't have separate throttle and mixture controls.
They don't suffer the problems associated with incorrect settings of those controls, namely knocking/detonation and pre-ignition.
Turbo-charging them does not carry the risk of pre-ignition and most of them are turbo-charged, so the performance does not decline as fast with density altitude.
There is lower risk of fire since jet/diesel fuel is less flammable (has higher ignition temperature).
Jet A-1 has much wider availability, especially in the third world, so it's easier to plan for fuel stops on a flight through say, Latin America or Africa

Disadvantages

They are heavier for the same power, because they need to be made from stronger material due to the higher compression ratio and because they need to have larger cylinder volume because of lower maximal rpm. On longer flights the reduction in fuel weight often makes up for the heavier engine.
Turbo-charging comes with specific operating procedures unfamiliar to those used to normally aspirated engines and a slight lag in thrust lever (it's not a throttle) response.
As others mentioned, small airports may not have jet fuel yet. This is probably better in Europe where the pressure to phase out 100LL avgas is stronger. Some engines also use automobile diesel fuel or even either jet or diesel fuel as diesel engines are less picky about what they burn.


Can helicopter rotor produce infrasound? While watching a Mil Mi-17 helicopter takeoff I experienced strange thing. The helicopter produces a lot of noise even when just starting the engines.

But shortly before taking off the high-pitched sound of the jet engines changed somehow (I guess changing the tilt of the rotor blades) and I felt some sort o pulsing "sound" which I felt rather with my belly than with my ears. Really unpleasant experience.

Could it be infrasound?

Yes. Each rotor blade produces a pressure wave. Here's an example from a Chinook:

At a rotor speed of 4 rotations per second, that's 12 pressure spikes per second, or a frequency of 12 Hz. At frequencies that low, you can hear the individual waves rather than a coherent tone (try this Youtube video on a good set of headphones).

At high levels you tend to feel more than hear this frequency: you can feel the pressure variations on your skin, your eardrums and in your lungs, and you could get resonances in your body.


What is this business jet? It could be a Learjet, but I can't find a match.

The tail is quite unique. I thought about Embraer Phenom, Hondajet, and Cessna Citation, but it is none of these.

I believe that your images are showing a British Aerospace 125 (aka Hawker 800/1000, or DH125 Jet Dragon). They were produced from 1977 to 2013, and most of them have been in service for the air forces of Japan, Brazil, and Saudi Arabia.

Source: wikimedia.org


What happens if you exceed the maximum speed on a C172? The airspeed indicator has a red marking that means: "never exceed this speed" ($V_{NE}$, around 160 KIAS). Why can't you exceed that speed?

You can, but you have to live with the consequences. There are several things that can happen:

Depending on the vertical gusts ahead, you might not even get close to v$_{NE}$. There is another speed limit for gusty weather called v$_B$, and exceeding this will run the risk of overstressing the wing structure. Going above v$_B$ will overstress the wings in a gust of more than 50 ft/s, and more than 25 ft/s when flying above v$_D$. The exact values can be found in the flight envelope diagram of the flight manual.
On a calm day, you can fly v$_{NE}$ and even a little faster, but once you fly fast enough, flutter will become very likely. Note that flutter needs some initial excitation, so you might fly well into the flutter speed range before flutter occurs. When it does, control surfaces will be ripped from their fittings which will make the aircraft pitch up. At that point the wings will break off.
The engine on a C 172 is not powerful enough to sustain level flight at v$_{NE}$. You need to dive the aircraft, which requires some altitude. Maintaining the speed will mean that you dive into the ground, so you need to pull out of the dive in time.
On really fast aircraft the pitch trim will get more nose-heavy when the aircraft approaches the speed of sound. You don't run that risk in a C 172, but faster aircraft found themselves locked into a dive which they could not end.


In a pusher configuration with turboprop(s), how is the superhot exhaust avoided? I actually looked around for turboprops in a pusher configuration, and so far I only found one: P180 Avanti. You can see the propellers are behind the turbine, and in fact it looks like two exhaust ports lead right into the propellers.

How is this possible? Turbine exhaust is very, very hot. "Superheated steam" is actually a technically accurate term. Won't this disturb the propellers and cause them to fail or else need huge maintenance? Is there some elegant way to avoid this geometry in a pusher configuration?

Because the blade is moving in and out of the exhaust stream at high velocity, and the exhaust stream is perhaps 20% of the total exposure, the heat transfer to the blades is negligible from the standpoint of heating up aluminum enough to affect its heat treat, or heating epoxy to its transition temperature.  Meanwhile there are the anti-icing benefits.

There is an issue with the exhaust impinging on the prop on the Avanti, and there is a Hartzel Service Bulletin http://hartzellprop.com/wp-content/uploads/SB181A-R06-W.pdf that covers it.   The carbon and heat from the exhaust attacks the aluminum of the blade and the problem is blade corrosion once the paint finish starts to erode.  The SB is to inspect, clean up, and repaint the blades from this damage.  (Carbon and aluminum are at opposite ends of the galvanic scale and don't like to live together; this caused much grief on the CRJ program when someone who evidently missed their corrosion module in university decided to put carbon floor panels on aluminum support beams without an adequate barrier, with unfortunate results and driving a switch to titanium beams).

Really though, with the Avanti the biggest problem is the prop directly behind the gear acting like a FOD catcher for stuff thrown up by the tires.  You wouldn't want to try to fly an Avanti off a gravel strip, that's for sure.


How frequently do civilian aircraft have mechanical issues to which passengers are oblivious? I know that aircraft are pretty well built and maintained, but I am certain that while flying these aircraft also suffer from some or the other mechanical issues. I believe redundancy plays a huge part in keeping these aircraft in air, but how many times are the passengers really oblivious to the problems? What are some of the most common problems that pilots are used to?

I don't think you'll find a definitive answer because most will be just considered routine items, but if you're including non-safety-critical items then I imagine the answer is "lots". Passenger aircraft are huge, complex, mechanical devices with many many parts. It is accepted and expected that some of these things will occasionally fail.
Most of these can fail gracefully without impacting the flight in any way beyond a note in the tech log. Not only that, but lots of things can be known to have failed but still allow the flight to go ahead as normal.
You may wish to explore the idea of Minimum Equipment Lists. These provide exhaustive lists of items which can fail and flights can still be dispatched as normal. Note this isn't the same as an in-flight failure occurring and continuing to the destination - items in these lists can be failed before you even take off.
For example, here's one for the Airbus A320: https://fsims.faa.gov/wdocs/mmel/a-320%20r21.pdf
Everything listed in that document can be failed in some way, but a flight still operate as normal (with exceptions, as per the remarks column)
For example, and to highlight the level of detail, an Airbus A380 does not need to be grounded because the "PA In Use" notification light doesn't work.


Does an aircraft like the Airbus A-320 have external sensors to detect damage to the aircraft? I read a news item recently . According to the article, the wingtip of an Airbus A-320 collided with the left wing of an A-330 while on the taxiway at Mumbai airport. The A-320 (VT-IFP) experience a damaged sharklet. The collision was observed by a passenger and then shared with the aircraft staff (flight attendants I guess) who informed the captain. The plane was led to a hangar, passengers de-boarded and sent on other plane/s by the airline.

What I want to know is: aren't there any sensors which can detect an impact and give/share that information to the pilot? I do understand that the airplane takes a lot of jerk and movement during takeoff and landing as well as during turbulence.

But when damage as such as the one described above happens, why isn't there some automated system that could inform the pilot instead of having to rely on a passenger's keen eyes?

This is related to an answer I gave here about why aircraft typically do not have mirrors and external cameras.

Short answer: yes aircraft do have sensors to detect damage, but not the kind of damage you're talking about.

Long answer: to design or decide what sensors to put on the aircraft and where, we have to get started with failure modes. There are at least a million way for components to fail, however, some failure are more likely to occur than others.

Do we have sensors which detect failures / abnormal situations? We do! We have sensors for control surfaces, hydraulics, gears, tire pressure, cabin pressure, engine temperature, oil pressure etc.

Here is an image of one of the cockpit screens on a Boeing:

(source)

OK, so why not more sensors?

Because sensors can fail. Now that would be a nightmare to troubleshoot: the sensor says the right outer landing light is not illuminated. Is that true? Let me exit the aircraft and take a look......

It turns out that:

Many failure modes are "internal", e.g. a valve malfunctioning. They are invisible on the exterior of an aircraft.
Aircraft rarely collide with any other objects.
Relying on visual indication is actually a good thing, because it is reliable and it's free.
Building an array of sensors covering each skin on the aircraft would be extremely complex, the construction cost would be high and the system would be heavy.
Sensors are just another component of the system. The more sensors, the more likely something will fail. At some point one has to trust the underlying component to function without relying on system indications.

Perhaps this is the kind of system you have in mind:

(Screenshot of "Stealth" (2005), 01:01:11)

Nah, that's just Hollywood artistic license.


Runway incursion episode/incident Situation: I’m at the uncontrolled small airport (one runway and one taxi way).  The runway in the direction I will be taking requires backtaxing. I’m ready to taxi, I check the radio and get ‘clear and loud’ back.  I pull up to hold short lines, check the downwind, base and final, announce that I’ll be starting backtaxing and pull up to the runway (i.e. facing the final). To my horror I discover that there is an aircraft that must have just turn final. I execute 180 and exit the runway. The other aircraft lands and I re-enter the runway, backtaxi and take off. After I land I find a message from the owner of the flight school/club that own the place I used. He says that the airport called him, saying that I taxied in the line of approaching aircraft, but I couldn’t be reached on the radio. In fact, I did not hear anything during the entire episode (either from the airport, or the approaching aircraft). During my flight (1.7 hr) I used the radio repeatedly without any problems.
I am, of course, hugely embarrassed about the whole episode/incident. I’m a new pilot (130 hours) and I love the place where I rent the planes. I haven’t yet heard from the owner of this school/club (other than the initial voicemail), but I wonder if you could help me to answer the following: (a). what likely legal consequences will I face and (b) even if I don’t face any legal  consequences, is it likely that I will be banned from renting this school/club planes in the future.

From your description, you did nothing wrong. But, there is a possibility that one of you was on the wrong frequency. It is hard to prove that unless the radio calls were recorded. There is iPad software for recording your radio transmissions.
The more important lesson to be learned is that a nontowered  field is supposed to be pilot-controlled. But, it is perfectly legal to fly in pilot-controlled airspace without talking on the radio. Even if neither of you made a radio call, you would be within the FAA regulations.
The mistake that was made was that neither of you maintained situational awareness. You should always visually clear the traffic pattern while taxiing to and holding short of the runway. This is especially true for final approach. In the case of a high-wing aircraft, you will have to angle the nose of your aircraft downwind toward final. Otherwise, your wing will block your view of final.
P.S. It might not be a bad idea to file a NASA report.


What charts do I need flying VFR between KPRC and KLAS? Some friends and I are going to fly up to Vegas from college to watch the Red Bull air races in a few weeks.  And after looking at the charts, I realized I am in a pretty unique situation.

The Phoenix sectional ends just short of Vegas - so normally I would buy a Vegas sectional.  However, the KLAS TAC extends just into the Phoenix sectional.

Should I buy the Vegas sectional as well, or can I just use the KLAS TAC once the Phoenix sectional ends?

If I understand correctly, your question is "can I substitute a TAC for a sectional on a cross-country flight?" However, assuming that you're flying under part 91, there is no legal requirement to have any charts on board at all. 91.503 does require them, but only for large and turbine aircraft, and the FAA has stated that electronic charts are allowed instead of paper.

There are a few places where it is required to carry a chart in the aircraft, per the Special Flight Rules Area regulations in 14 CFR 93. Some examples are:

Near Los Angeles International Airport (93.95(c))
The Hudson and East River Exclusions in New York City (93.351(d))

So unless 91.503 or one of the part 93 rules applies to your flight, legally you can carry whatever paper, electronic or hand-drawn charts you like - or none at all - although if you bust restricted airspace and the FAA come after you, not having charts on board may not look good. (Of course, if you do have them then the implication would be that you didn't use them or don't know how to read them, which isn't good either.)


How does one interpret the satellite data on flight MH370? There seems to be a problem with some of the data released by the satellite company Inmarsat.

Specifically, the handshake at 00:10:58 on 7/03/2014.

In the left column the difference in time-stamp between the ground station initiating the request and the receipt of the return signal from the aircraft is given as 1.928 seconds. However, the prior handshakes at 19:41, 20:41, 21:41, and 22:41 took 1.996, 1.997, 1.998, and 1.999 seconds.

This would imply that the round trip distance between the ground station and the aircraft changed by about 13,000 miles in 1.5 hours.  What gives?

TL;DR.

Use the BTO not the difference in time-stamps for request & acknowledge.
BTO is an offset in μs, not a round-trip time.
There's a mean bias value (-495,679 μs) that includes the signal processing delays in equipment.
The distance is ground-station to satellite to aircraft to satellite to ground-station.

Inmarsat data

As I understand it, to calculate distance you should be starting with the Burst Timing Offset (BTO) not the difference between time-stamps in the Inmarsat data. There are latencies in various stages in the electronic processing of messages, not all of these are distance related.

Time    BTO(μS)
19:41   11500
20:41   11740
21:41   12780
22:41   14540
00:10   18040

There's an example on page 54 of MH370 - Definition of Underwater Search Areas:

The aircraft AND the satellite are in motion in three dimensions

The satellite is at an altitude of around 35,811 km above the earth's surface, the satellite is moving cyclically north and south of the equator and the aircraft is flying over a roughly oblate spheroid so changes in it's distance from the satellite are not a simple function of changes in the aircraft position relative to the surface.

Not to scale. E&OE. etc

References

Inmarsat 3-F1 satellite position
Inmarsat 3-F1 satellite tracking
Inmarsat raw log data for MH370
MH370 - Definition of Underwater Search Areas


Does a RC aircraft require suspension in landing gears? we engineering students are preparing for a particular competition with dimensions of 170 in. (length + breadth + width) for that competition we require landing gear but for that are we supposed to use suspension in it?

For one that size, you'll certainly need some spring in the landing gear, but it's likely that shock absorbers are still unneeded.  Most models use spring wire landing gear legs, at least up to around 5 kg weight.  As big as your model will be, you may need hinged gear legs with spring return, or something similar.

I'd suggest looking at the landing gear for smaller crewed aircraft (like a Cessna 152 or Piper Tomahawk).  The smaller Cessnas for certain have only spring legs for the main gear, though they use a shock strut for the nose.  Scale down from their practice and you should be good (though scaling down frequently means simplifying, as well as making smaller).


How should a Traffic Control Tower notify aircraft that their frequency just changed? What is the policy for ATC towers to notify aircraft the frequency they broadcast and monitor on has changed? How do they do it, if radio isn't available (because they just changed their frequency)?

ATC frequencies don't change very often, but when they do they are planned well in advance.  NOTAM's are issued ahead of time to let people know, and if the airport has ATIS they will include the new frequency on the ATIS.

If it is an enroute frequency, the other controllers will simply hand you off to the new frequency, and you don't even need to know about it ahead of time.


What is the visual difference between turbine fans and compressor fans? How to identify that a given fan is a compressor fan or a turbine fan, just by visual inspection? Also, can visual inspection of a fan help in identifying the compressor/turbine stage i.e. if the fan is from a High Pressure Turbine/Compressor blade or Low Pressure Turbine/Compressor blade?

Assuming we are speaking of axial compressors/turbines

Compressor blades are generally thin and straight, and resemble a tiny rectangular wing with low camber thickness.

Image source

Turbine blades are more curved, often in almost "U" shapes (like the ones seen here). In particularly large and recent engines, where efficiency is critical, turbine blades will often be full of tiny holes:

Image source

To distinguish between high pressure and low pressure stages (compressor or turbine does not matter), the length of the blade and its torsion (i.e. how much the aerodynamic profile turns around the axis of the blade going from the root to the tip) are key: shorter and more twisted blades will be high pressure ones, longer and straighter blades will be low pressure.

Note that two blades of the same length could come one from a high pressure stage and the other from a low pressure one of a different engine: "short" and "long" are relative to the engine size.

On the other hand, radial compressors and radial turbines are more difficult to distinguish.


What is the peak of coffin corner called? The converging point of Vx and Vy is the absolute ceiling. Can I call the peak of the coffin corner an absolute ceiling as well?

Yes.

The peak is the actual coffin corner. That's why it is called a corner.

In the coffin corner the aircraft cannot climb any higher, which is a definition for the absolute ceiling. Going any faster will reduce L/D and cause the aircraft to sink; that Mach effects are involved is of minor importance. Going slower will also decrease L/D because the aircraft is approaching stall.

What is special about the coffin corner is not the corner itself, but what happens when the aircraft gets too fast: Now stronger shocks will increase drag and decrease the maximum lift coefficient such that the aircraft is locked into a shallow dive from which it is initially not able to recover. Going too fast while flying at the "regular" absolute ceiling merely means that you will lose some altitude but not lose control.


Is this Corrected Mass Flow equation correct? I have an engine air mass flow rate (322 kg/s) which I would like to convert to a corrected mass flow rate at 10000 feet.

I have tried using the equation found here. However, this article lacks any sources and I have struggled to find any other reliable sources online.

I have made an attempt using the equation in the article but have gotten a greater mass flow than 322, which doesn't make sense.

Is the equation in the article correct or am I just calculating this wrong?

For 10000 ft I get:

Temperature 268K
Pressure 69.6817 KPa

So
Theta = 0.9301 and Delta = 0.6877

Which gives a corrected mass flow of 451 kg/s.

The equations on Wikipedia are correct (see Flack, for example). I believe your error is in their interpretation. You say that you are given a mass flow rate and want to "convert [it] to a corrected mass flow rate at 10000 feet." But the direction you take the equations is as if you have a mass flow rate at 10000 feet and want to convert it to the mass flow at sea level. If the latter is what you intended, then I see no error. If the former, you need to invert the equation.


Why is the combustion temperature in a turbojet engine kept low? Why the temperature of hot gas entering the turbine is maintained  far below the adiabatic combustion temperature?

Because the fuel-air mixture in a turbine is much leaner than what it would be for a stoichiometric combustion. It needs to stay lean to restrict the maximum gas temperature inside the engine - higher temperatures lead to exponentially shorter lives of the turbine components.


What are the WAAS requirements for RNAV (GPS) approaches? Is a WAAS GPS required to fly in RNP airspace (e.g., RNAV (GPS) approaches)?

Or, can you be approved to fly RNAV (GPS) approaches with, say a military EGI (embedded GPS/INS)?

(skyvector.com)

This is a random RNAV (GPS) approach. The answer is it depends on the minima, I highlighted above two examples.

The LP (WAAS / SBAS) approach requirements can be found in the FAA AC 90-107.

To fly the LP approach, the GPS unit on your plane (among other things) needs to be LP certified. For example, a Garmin GNS 480 unit is LNAV/VNAV approach approved, and only LP approved if you have software 2.3 or later installed.

If you want the regulatory requirements, then check the AC linked above and all the referenced technical documents (such as TSO-C146). If you want to check the capability of your GPS unit, then refer back to the manufacturer.


Is it possible to eliminate induced drag completely? According to Wikipedia an airfoil of infinite length would create zero induced drag. Therefore, would it be possible to make a wing that creates no drag if you ignore viscous effects (skin friction) by walling it off on the wingtips to prevent vortex formation? Or is there another drag creating mechanism?

The infinite span has nothing at all to do with having no ends.

The ratio of lift to induced drag increases with span. If you fix the lift, and vary span, the induced drag will tend to zero as the span tends to infinity. That means in limit a wing of infinite span generating finite lift (and therefore flying at zero coefficient of lift!) will have zero induced drag.

This is a highly abstract approach to things and I don't think it provides any useful insight.

Anyway, forget about the vortices. They only happen behind the wing anyway and therefore are obviously irrelevant! Instead, call upon the good old laws of motion. The lift is upward force of the air on the wing. By principle of action and reaction (Newton's 3. law) the wing must apply force of equal magnitude and opposite direction, that is downward, on the air. Now if the ambient pressure above and below the wing is the same, this force will accelerate the air downward, which will increase its kinetic energy. And by law of conservation of energy, this energy has to come from somewhere and the only way work can be done here is by drag.

This suggests the way to reduce it. If the pressure can be increased below the wing without accelerating the air, there won't be induced drag. Well, that's exactly how ground effect reduces drag. Normally it does not eliminate it, because the air can still move outward, but a wing flying in a trench could perhaps get quite close (though not to zero, because the air still needs to move at least a bit to maintain the pressure difference).


Can Turborockets replace Pure Rockets? Would it be possible for a aircraft to deliver a payload into space using a turbojet-rocket hybrid? Merits are that they don't have to carry tons of oxidizer like a rocket would have to. It still may need to carry some but only when the atmosphere gets so thin. But even there is a lot of weight saving which means huge savings in fuel cost. Can Projects like the Skylon Space Craft really work or are they just fantasy?

Turborockets are hybrid systems that aim to use atmospheric oxygen as oxidizer instead of carrying it on board and thereby improve performance. While they do have a real chance of replacing the conventional rockets in use today, there are a number of engineering challenges to be overcome before they become viable.

These hybrid systems basically use a gas turbine inside the atmosphere (ramjets/scramjets have also been proposed) to produce thrust. The issue is that the jet engine becomes dead weight outside the atmosphere, so its weight has to be minimized. Skylon uses a slightly different method with a heat exchanger using helium, but the problem is the same.
The air intake has to operate over a wide range of speeds, from subsonic to hypersonic; the best option is to have a variable air intake, which adds weight and complexity.
The nozzle has the same problem. The area ratio of the nozzle has to vary significantly to cope with widely differing flow conditions.
If the vehicle has to take off under its own power, it has to have lifting surfaces, which are dead weight (eating into payload) once out of the atmosphere.
The integration of all these extra systems also causes a significant weight penalty.

The addition of all these systems increases weight more than the weight of the oxidizer they replace. This demands extremely high performance materials and very high efficiency systems for the vehicle to be commercially viable.


Were there any folding wing biplanes? Given that several nations had operational carriers by 1920 and biplanes were still in military service, were there any folding wing biplanes?

Wikipedia: United States first purpose built aircraft carrier, USS Langley (1920), note no biplanes have wings folded.

The Blackburn Ripon -- a British carrier-based torpedo bomber -- is such example (first flight 1926):

Source: aviadejavu.ru via Flight

Source: Imperial War Museums -- seen here landing on HMS Furious

Earliest mentions I found -- not necessarily carrier-based, and not necessarily real(?):

Source: Flight -- 1911

Source: Flight -- folding wings on the aerial-saw concept from 1915 (click image to view)