Do fighter jets have deicing in their wings? If there is such thing as deicing for fighters? If so, is bleed air or electric heating preferred? I could not imagine that a $50MLN fighter jet would not be able to get the ice off its wings.

No they do not nor are there any modern fighters that I am aware of that are intended to operate in icing conditions nor would they pass the FAA’s certification processes for flight into known icing.

As an example from the Grumman F-14D NATOPS Flight Manual, Section 18 - Extreme Weather Operations.  The basics are that Tomcat aircrews are advised to avoid areas where icing is probable and that extended flight in an icing environment is considered an emergency.

  Icing conditions should be avoided whenever possible. Before flight, check freezing levels and areas of probable icing from weather service.

  The primary concern with flying in icing conditions is ice accumulation sufficient to cause engine damage. Ice accumulation on engine probes located between the engine guide vanes and above the number three inlet ramp is not detectable from the cockpit. Aircraft maneuvers or landing impact can dislodge accumulated ice and can cause severe FOD to the engine. Visual detection of icing on exterior surfaces and/or illumination of the pilot’s INLET ICE caution light should be treated as indications of the potentially more serious problems described above. The following precautionary action should be taken immediately in known or suspected icing environments:

  ANTI−ICE switch  ORIDE/ON.
  CABIN AIR DEFOG lever  FWD DEFOG.
  Engine instruments  Monitor Frequently.

  Carefully monitor rpm and EGT indications. A reduction of rpm or an increase in EGT accompanied by a loss of thrust is an indication of engine icing.

  Avoid clouds and other areas of visible precipitation.
  If unable to avoid precipitation, adjust aircraft Mach or altitude as necessary to remain outside of the icing zone shown in Figure 18−1.

  Extended operations in icing conditions should be considered an emergency situation. If time and fuel permit, a descent below the freezing level is recommended. If unable, altitudes above approximately 25,000 feet or ambient temperatures below −30°C are generally free of icing conditions. If inadvertent or unavoidable operation in known or suspected icing conditions has occurred, an effort should 18.1.

  Before flight, check freezing levels and areas of probable icing from weather service.
  The primary concern with flying in icing conditions is ice accumulation sufficient to cause engine damage. Ice accumulation on engine probes located between the engine guide vanes and above the number three inlet ramp is not detectable from the cockpit. Aircraft maneuvers or landing impact can dislodge accumulated ice and can cause severe FOD to the engine. Visual detection of icing on exterior surfaces and/or illumination of the pilot’s INLET ICE caution light should be treated as indications of the potentially more serious problems described above. The following precautionary action should be taken immediately in known or suspected icing environments:

  ANTI−ICE switch  ORIDE/ON.
  CABIN AIR DEFOG lever  FWD DEFOG.
  Engine instruments  Monitor Frequently.
  Carefully monitor rpm and EGT indications. A reduction of rpm or an increase in EGT accompanied by a loss of thrust is an indication of engine icing.
  4.Avoid clouds and other areas of visible precipitation.
  If unable to avoid precipitation, adjust aircraft Mach or altitude as necessary to remain outside of the icing zone shown in Figure 18−1.

  Extended operations in icing conditions should be considered an emergency situation. If time and fuel permit, a descent below the freezing level is recommended. If unable, altitudes above approximately 25,000 feet or ambient temperatures below −30°C are generally free of icing conditions. If inadvertent or unavoidable operation in known or suspected icing conditions has occurred, an effort should
  be made to eliminate the ice before landing by remaining well below the freezing level for an extended period of time.

  WARNING: Icing conditions can cause heavy ice accumulation in the inlet ramp areas or on engine probes and the compressor face. Aircraft maneuvers and arrested landings may dislodge this accumulation and cause extensive engine FOD or failure. A straight−in field landing is preferred. Minimum power setting after landing is recommended.

Similarly the F-16 A/B flight manual offers similar advice:

  Flight in areas of icing should be avoided whenever possible. If icing conditions are anticipated or cannot be avoided, tum ANTI ICE switch to ON ~ and PROBE HEAT switch to PROBE HEAT. Frequently check the aircraft leading edges for indication of ice buildup. Make all throttle movements slower than normal when in potential icing conditions to reduce possibility of engine stalls and/or stagnation. Consider diverting to an alternate field if required to avoid icing conditions.

Fighter aircraft, with their thin, low aspect wings and sharp leading edges are actually more susceptible to ice accumulation than other kinds of aircraft wings.  They do have one advantage in the sheer climbing power and maneuvering capability to get out of an icing area with a slow to moderate accumulation rate.  Fast ice accumulation could be very dangerous to an fighter, especially during low speed operations ie descent into a terminal environment and landing in marginal weather.


What is a flat rated engine? I've heard that a "Flat Rated Engine" is an engine where the power is reduced to keep the internal temperature within certain limits when the ambient temperature is above a certain point. Is that correct? How does it work?

Yes, a flat rated engine (my familiarity is with gas turbines, but the concept may apply to other engine types), is an engine for which the control system is designed to achieve the same level of thrust (hence the "flat" term), up to a certain OAT, then for higher ambient temperatures, the level of thrust decreases as a function of OAT, normally in a pretty linear fashion. This control system operation gives identical performance over the flat portion of the OAT range even while the engine degrades (until it degrades to the point it hits the EGT limit), making the plane performance predictable. But for higher OATs, it stops the EGT continuing to increase. The temperature at which the thrust starts to decrease is typically 25 or 30 deg C, and can be found in the EASA or FAA engine type certificates (e.g. see section 6 of this EASA one for the CFM56-5). See the graph from this CFM56 document below. So, your understanding was correct.


What should the pilots do when fire is detected during the takeoff roll at high speed? Let us say fire or smoke is detected during a takeoff roll when the speed is so high that the pilots can not make a full stop using the remaining runway. What is the best option: using full brake to stop even if that will cause a runway excursion or continue the takeoff and re-land?

Before starting the takeoff, the pilots will have calculated at least 3 V speeds: V1, VR and V2. The important one for your question is V1, the takeoff decision speed. This is the critical speed that determines whether or not to reject the takeoff in case of a critical failure or other problems.
During the takeoff, there are 3 phases relevant for the decision of rejecting:

Until reaching 80 knots: At these relatively low speeds, you would reject the takeoff for any reason. Any caution message appearing or any failure you notice results in rejecting the takeoff.
Between 80 knots and V1: At these speeds, you would only reject for critical failures, like e.g. an engine failure or a fire warning.
At or after V1: At these speeds, you should never reject the takeoff unless the captain determines that the aircraft is unable to fly.

The details may depend on the exact aircraft, but here is the official list of reasons for rejecting for the Boeing 737 NG:

Prior to 80 knots, the takeoff should be rejected for any of the
following:

activation of the master caution system
system failure(s)
unusual noise or vibration
tire failure
abnormally slow acceleration
takeoff configuration warning
fire or fire warning
engine failure
predictive windshear warning
if a side window opens
if the airplane is unsafe or unable to fly.

Above 80 knots and prior to V1, the takeoff should be rejected for any
of the following:

fire or fire warning
engine failure
predictive windshear warning
if the airplane is unsafe or unable to fly.

(Boeing 737 NG QRH MAN 1.2 - Maneuvers - Non-Normal Maneuvers, emphasis mine)
As you can see, a fire or fire warning is serious enough that you want to reject up to V1. At or after V1, you should not reject for a fire warning. Rejecting a takeoff after V1 usually results in an accident, even if there is enough runway available, because the brakes may not be capable of stopping the aircraft any more:

Rejecting the takeoff after V1 is not recommended unless the captain judges the
airplane incapable of flight. Even if excess runway remains after V1, there is no
assurance that the brakes have the capacity to stop the airplane before the end of
the runway.

(Boeing 737 NG FCTM 3.23 - Takeoff and Initial Climb)


Are there procedures to follow in case of a suspect Electronic Control override (hacking)? I am a filmmaker who made a film most pilots have seen (405) http://youtu.be/Tpx6o4gvmXE

I am working a new production that also takes place aboard an airliner. In it a telekinetic little girl is overriding the flight controls. But it is thought to be some sort of electronic control interference for a short time. Are there procedures a flight crew would follow in the initial stages if their controls seemed "possessed?"

There are procedures for when some instrument indicates false values for how to find which one is not to be trusted and what to do if particular instrument cannot be trusted.

But for primary flight controls, not really. If the aircraft is flying on autopilot and initiates unexpected manoeuvre, the pilot will hit the autopilot disconnect button and take over manually. But beyond that, the pilot will just try more pressure on the controls to get the plane where he needs to. And won't really have much time to think about the reason.

You may want to look at the incidents and accidents caused by B737 rudder reversal. The rudder suddenly deflected in opposite direction than commanded and the pilots were not really able to understand what is happening in the short time they had to react. Somewhat similar incidents where the rudder failures of B747 (Northwest 85, here is captains account of the incident; there was one other similar occurrence). Again, the pilots just fought the controls; finding out what happened was not really possible and wouldn't help much anyway.

So I'd say there is really no time to "think it to be some sort of electronic control interference". The pilots would simply disconnect autopilot (if it didn't disconnect already due to pressure on controls) and then they would fight the controls.

Note that in all aircraft except Airbus A320 and newer and Boeing 777 and 787 the control column is mechanically (cables in smaller aircraft, hydraulically with some kind of power amplification on larger ones) connected to the control surfaces. So the pilots would be directly fighting the telekinetic power with their muscles. On Boeing 777 and 787 there is electronic intermediary, but the link is still bidirectional and control column position still corresponds to control surface position.

Only Airbus A320 and newer has the side-stick connected to a computer that calculates the final command from the pilot input and inertial reference. In this case the telekinet would either try to move the surfaces, but then would be fighting the computer, which has all power of the hydraulic system to it's disposal, or would try to move the side-stick under pilot's hand, but then the other pilot could press control priority button to take over. Of course even on Airbus the pilots can pull the circuit breaker and disable the computer, but then they are left with trim wheels and rudder pedals that both do have direct hydraulic links.


Are airliner flight plans/routes preset? KLM has 3 flights daily from BLQ to AMS.

How do all of the crews handle the flight plans? Do the make a plan for every flight every day or do they have a database in which preset and stored flight plans are available and are ready to be extracted?

Airlines have an own department that is solely responsible for their flights and flight plans: Dispatch. Since single airways can have different availability or just direction for different days or even times of the day, there will be a preset pool of routes for recurring flights, which can then be adapted for anything out of the ordinary, like NOTAMS, weather forecasts, operational requirements like airspace closure, etc...

The flight plan is usually submitted by the dispatchers and not the aircrew.


Can I file IFR DIRECT with a non-WAAS GPS? The AIM 1-1-17 2 (a) states:

  Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for
  navigation under IFR must be equipped with an alternate approved and
  operational means of navigation suitable for navigating the proposed
  route of flight. (Examples of alternate navigation equipment include
  VOR or DME/DME/IRU capability). Active monitoring of alternative
  navigation equipment is not required when RAIM is available for
  integrity monitoring. Active monitoring of an alternate means of
  navigation is required when the GPS RAIM capability is lost.

Does this mean that if I have a non-WAAS GPS unit then I have to file only along Victor airways or between VORs? Or can I file DIRECT?

This question was answered here on this Website.  Read the second answer.

Yes you can file direct even without a GPS.  However it would be advisable to perform a RAIM check during your pre-flight along your intended route and determine that you would be in RAIM during the route.  If for some reason your GPS loses RAIM capability then you should proceed using VOR/DME/ADF.  You can still fly direct with using only VORs although that will be more difficult.


How do I figure out the right pronunciation for transitions? For example, the CNERY transition,* how exactly is this pronounced? On the VATSIM community, it seems there's a huge debate on what this is called. Some people say CONNERY, and some people say SCENERY. I personally say SCENERY since it makes more sense, but what is the most proper one? And is there a place where we can find pronunciation of such things?

Like another one is SCTRR transition which some people say SCOOTER, some people say SCATTER.

* CNERY transition is part of KLAX's DOTSS TWO DEPARTURE.

It would be nice if there were an authoritative, canonical, source for these sorts of waypoints, but sadly, I don't think one exists. I say that because I hear controllers sometimes using a different set of vowels or syllable emphasis "today" than they did "yesterday". If there were a single "right" way to verbalize CNERY or SCTRR, I'd expect ATC to have them all down. But in plenty of cases beyond those two, it remains unclear.

For example, the JFRYE arrival into Dallas -- is it the "Jeffrey" or the "J-Fry" arrival? You hear both from Ft Worth Center all the time.

My conclusion: no cannonical source exists.


Can I log this as total time? I am a CFII who has a commercial multi-engine certificate. My friend was building time in a BE-58 Baron (multi-engine) for his MEI. He asked me to tag along (right seat)since he was going to file IFR and fly in some IMC.
Since he is logging the PIC, and all I did was tune in the freqs and programmed the avionics, can I log this as total time?
Also since we flew in IMC can I log the “Actual Inst” time?

The regulations regarding the logging of time are specified in FAR Part 61.51 (Pilot Logbooks):

(a) Training time and aeronautical experience. Each person must document and record the following time in a manner acceptable to the Administrator:
(1) Training and aeronautical experience used to meet the requirements for a certificate, rating, or flight review of this part.
(2) The aeronautical experience required for meeting the recent flight experience requirements of this part.

Time other than (1) and (2) above does not need to be logged as it can't be used other than as specified in (1) and (2) above.
That being said, you can put/log what ever you want in your logbook in order to record the flight for historical purposes.  But as for "Total Time" to satisfy the requirements for a certificate, rating, or flight review OR the aeronautical experience required for meeting the recent flight experience requirements of Part 61, the time you are with your friend (as a tag along, and not giving instruction) cannot be used for any purpose specified under 61.51.
Further, since you are not performing the duties of a safety pilot, a required crew member or in any required capacity as a pilot, you can't, for the purposes of meeting any requirements/conditions specified under FAR 61.51, log and receive benefit of the time as "Actual Instrument" time.


What causes a taildragger to lift its tail during the takeoff roll? The rear of a taildragger is closer to the ground than the front. As the aircraft moves forward (I guess at its stall speed), its tail rises up and the aircraft moves with the fuselage level before takeoff (As seen here). But why? Does the pilot change the elevator?

Yes, when the plane exceeds a certain speed (known to the pilot!), the pilot then pushes the stick slightly forward and this lifts the tail off the ground. This reduces rolling drag and sets up the angle of attack of the wing for takeoff. For very powerful airplanes, the tail will sometimes come up on its own and surprise the pilot during the takeoff roll.
In some planes, the resulting angle of attack is enough that the plane will fly itself off the ground and begin climbing when it has picked up enough speed in the roll. In other designs, the pilot will wait for the right speed and then gently pull back on the stick to increase the AoA a bit and the plane then takes off.


Can commercial airplanes be converted to drones? Is it possible to convert a commercial airplane into a drone, such that if a pilot fails to respond to ATC it can be remotely piloted?

Is it possible to convert a Commercial Airplane into a Drone

For what its worth, yes this would be technically possible however it comes with some risks.

When To Take Control: This brings into the simple idea that in an emergency the pilot may need to be in control of the situation as they often have the most information about exactly what is happening. If the plane had a serious issue and the ground controller did not know what was happening they may take control and only exacerbate the problem.

Connection Reliability: Keep in mind that planes are flying at very high altitudes moving quite fast. Maintaining a reliable connection in these conditions is difficult. Since a reliable connection is hard enough to maintain you again may create more issues than you solve. This also has to be a fully duplexed channel since the plane needs to transmit its telemetry and receive control inputs in what is more or less real time. At this point the data up/down rates would push the limits of what we can do today.

Connection Security: As mentioned you would need to secure the connection to prevent someone from taking it over maliciously. This in and of its self is a big problem. But lets not turn this into a digital security debate.

Cost: As nice as safety is its not free. Since there is currently no system in place on a global scale to do this it would have to be created. Someone has to pay for that and unless the FAA is going to require it you will have to get the airlines/aircraft makers on board with this voluntarily. On top of that any system that is added like this would have to be certified by the FAA.

So while it is possible there are very real barriers to a system like this include but are not limited to the ones listed above and before someone comes back with the "if it makes it safer than we should spend the time figuring it out" response I will mention that modern technology is as good as it is and there are already companies and individuals researching new tech like this but Keep in mind that with FAA regulations taking the time they do to get, planes are flying with tech that is now considered "dated" by the tech world.


Are there any low time lucky CPL holders who operate as PIC on medium or heavy jets? CPL holder can be PIC on any plane if it's not a commercial air transport. So if the flight is positioning, acceptance, testing, delivery or any other without cargo and passengers any CPL holder provided he/she has TR and special training for the left seat can act as PIC? Do airlines allow this maybe as bonus for young first officers?
Another option is big business jets like 737 747 BBJ, A319...

There have been periods of time in the past (and I think at present as well) where a lack of experienced pilots meant airlines had to resort to hiring CPL's as SIC's on turboprop and some regional jets. I know that American Eagle did that for a while -- they used to call them the 500 hour wonders. Some were hired with even less time if they showed exceptional skills.

However, to log PIC time in an aircraft that requires an ATP ticket, you have to have the ticket. Sole manipulator of the controls is not enough for a CPL to log the time as PIC on those aircraft.


Why do the ailerons of this flying wing work oppositely compared to those of an airplane? I made this simple wing glider and put some ailerons on it. I thought that the ailerons in this glider would work the same way it works on airplanes, wherein the roll will be in the direction of the aileron that is pulled up. However, the opposite happens. For example, when I pull the left aileron up and the right aileron down, instead of rolling to the left, it rolls to the right. What is the reason behind this? And what is the difference between the control of this flying wing to a conventional airplane?

Most likely the adverse yaw effect (due to the induced drag of the increased lift on the down-aileron side) is causing the wing to yaw the opposite direction from the intended roll, and the yaw causes the dihedral induced roll (proverse to the yaw) to override the aileron input.
This situation is very commonly seen with very slow flying model aircraft -- indoor Peanut scale, for instance, or Penny Plane models, will often be set to turn left by putting a relatively tiny tab under the left wing, where you'd expect the lift to cause a roll to the right.


What is a rule of thumb for when to begin a descent? What rule of thumb would you use for your airplane insofar as how far from your destination you would begin your descent given an expected straight-in approach and landing in no-wind conditions and no ATC or traffic restrictions? How would your weight influence that rule of thumb, bearing in mind that the heavier you are, the more potential energy you have to dissipate?

With those same conditions, what rule of thumb would you use to determine how close to the airport you could get before descending and still come straight in if you had an empty airplane save for necessary fuel and if you were allowed to use any aircraft configuration you wanted, and what would that configuration be?

Descent planning for jets can get a little tricky at times, and you have pointed out some of the things to look at when deciding when to start down (assuming that ATC gives you the option to choose your own top of descent).

The descent point is dependant on your aircraft and how much drag there is at your descent speed.  Anything that adds more drag allows you to come down faster, but also makes the flight less efficient since you would have burned less fuel had you just started down earlier without the drag.

A typical jet will descend with the engines at flight idle and the speed at the recommended descent speed, which is usually close to the maximum speed for the airplane.  A good rule of thumb for most jets would be:

  3 miles for each 1,000 ft. of altitude to lose + 1 mile for every 10 KIAS of airspeed that you need to lose before landing.

Example:

We are cruising along at 38 thousand feet and landing at an airport with an elevation of 2 thousand feet which means that we need to lose 36,000 ft.  Let's say that we will be descending at 350 KIAS and need to slow to 150 KIAS for landing:

  Thousands of feet to lose: $38-2=36$ thousand feet
  Tens of KIAS of airspeed to lose: $35-15=20$ tens of KIAS

  Distance = $36\times3+20=128NM$ from your destination

So in this case, we will start down 128 miles out.

There are various factors that can cause this to be a little off, the biggest being the wind.  As the descent progresses, you should mentally double check your progress.  In this case, maybe check when we have 20,000 ft to go (should be 80 NM out now) and when we have 10,000 ft to go (should be 50 NM out now).

If one of your checks indicates that you are a little off, you can adjust your descent rate (adding a little power or using spoilers to descend more quickly) to get back on track.

A slight variation of this uses the same calculations, but instead of using the airport as the "target" altitude and speed, they use a point 30 miles from the airport at 10,000 ft above the airport at 250 KIAS.

The above method is enough to get someone started, and just "works" most of the time.  As a pilot becomes more comfortable with the math, they can start to make adjustments for other factors like:

The effect of the winds at the various altitudes during the descent

Headwinds mean that you can wait a little longer to descend
Tailwinds mean that you should start down a little sooner

Weight of the aircraft

The lighter the aircraft, the later you can start your descent.  (If this seems backwards, consider that when you are heavy it will push the airspeed higher faster as you lower the nose and you will have to raise it to keep from overspeeding.  When light, you can keep the nose further down and will therefore have a higher descent rate.)

The direction that you are approaching the airport from

If you are landing straight in you should start sooner
If you are going to fly a downwind, base, and final, you can start a little later

ATC speed restrictions can prevent you from descending at your normal rate, so you may need to start down earlier.
Inoperative equipment (i.e. spoilers, etc.) may keep you from descending as fast so you may need to start down earlier.

As far as the configuration of the aircraft, in order to get the most fuel efficient profile, I would keep it clean as long as possible and start the descent at a point where I could glide for the majority of the descent and configure on speed for a stabilized landing in the normal landing configuration for the aircraft.  If this is your goal, then the use of spoilers is an indication of poor planning!  ;-)


How would a helicopter deal with auto rotation when it transports a hanging payload? How would a helicopter deal with auto rotation when it has a payload? Will it deploy it's payload and continue with auto rotation as normal? Can't find much online, this research is for my senior design.

Any help would be greatly appreciated. If you can give me something to read and learn further for myself, that would also be great.

In theory, with that load, the rotor revs will be higher during the descent, and releasing the load just before flaring will give the pilot more rotor energy to control the aircraft with the collective in the last stage of the landing.

But it would be more prudent, in my opinion, to release the load as soon as possible. After all, in any dead stick landing, the lighter the aircraft, the better...


How do I obtain the max endurance altitude? There are excellent explanations of the physics that determine maximum endurance speed here, here, and here.

I was thinking of aircraft that have to be "on station" without an indicated altitude and then wondering: Is maximum endurance not a function of both density altitude and speed?  If so, what are the relevant variables and equations?

(I imagine that maximum L/D is a function of Mach number, so that might conveniently account for the effect of change in air density with altitude.  But from the answers on max endurance speed I see that there are already differences between jets and props which, when air density is added, will result in further differences between turbo-props and piston props.)

The answer depends on many factors. Things to consider are:

Improved efficiency of combustion engines at higher altitude because of lower air temperature.
Lower power output with altitude due to lower air density, so the most efficient power setting coincides with the best endurance speed, which is close to stall speed.

But not all is better higher up:

Again due to lower temperature at higher altitude, the Reynolds number drops over altitude, even when the higher flight speed to compensate for the drop in air density is factored in. This increases the zero-lift drag and lowers the maximum lift coefficient. For propeller-driven high aspect ratio designs this alone lowers the maximum endurance altitude.

There is more, but those are the main factors. So it depends on engine characteristics, wing loading, planform and airfoil and even on atmospheric conditions. This makes it hard to give a generalised answer – in the end the optimum has to be found for each design individually.

With all caveats, a good candidate for the optimum endurance altitude is close to the service ceiling of the aircraft when optimum loiter speed can be flown at the cruise power setting of the engine. If winds allow: A maximum of wind speed occurs near the tropopause, and in order to keep station even in high winds, it might be impossible to fly at best loiter speed. There are stories of Me-109s which should be flown to the western front from the plant in Augsburg and ended up on airfields in Czechoslovakia, because the pilot got caught in the then-unknown jet stream.

Wind speed over altitude at 40N latitude (picture source).


How many hours to remove and install a Cherokee 180 engine and prop How many hours should it take a shop to remove, install, and adjust the engine in a Cherokee 180 with a fixed pitch prop?

This would include the baffles and any hardware needed to be removed and installed for an engine swap.

I once changed an engine in the bush when I was bush flying, helping the air service's mechanic.  It was a C-180 on floats (I had been forced down in it after the engine developed a loose cylinder from failed hold-down studs).

There was a rigid dock for us to work with at the remote lake we were at, and we used a bipod made of pine poles with a come-along to lift the engine and set it down on the dock (with the noses of the floats against the dock).

It took about 6-7 hours to have the engine and prop removed and ready to be loaded on the company Beaver when it showed up around 5 pm (loading it was the really entertaining part).

We went back in two weeks later with an overhauled engine and installed it, 2 mechanics and myself, and I flew it out that late afternoon around dinnertime.

So for a Cherokee sitting in a hangar with a lift handy, one mechanic with an assistant, about 4-6 hours to remove the engine, and about 6-8 hours to install it.  Certainly no more than two days at most.


Is excess fuel leaking normal during take off of a B737? When we look over this video

it's noted that some fuel is coming off from the left wing during the rotate. This is the position of the fuel vent within the wing, of course, 'leaking' due to new vertical and horizontal forces combined which, in turn, force fluids backwards and outwards in a swept wing, so not exactly a fuel dump procedure as published. My question is: is normal or correct for an airliner to have such an excess of fuel causing it to reach the fuel vent until it spills during take off? Shouldn't this wing carry less fuel?

EDIT: To help explain exactly what I am talking about, we are looking for a very thin trail of fuel coming from the fuel vent of the left wing. This vent is located under the wing and a little ahead the (left) aileron. We are not talking about a vortex from the engine vortex generators or from the flap edges. ;)

This:

This other video shows the same with much more detail:

No it is not normal. It can happen if the wing tanks are fully filled, typically for long trips or when the airline is tankering fuel to airports where fuel is more expensive. When cold fuel warms up it expands. With full tanks, the fuel has to go somewhere and it flows through the vent channels and will end up in the surge / vent tanks in the wing tips. From here the fuel can flow back into wing tanks (when there is space again) through a check valve.

 Boeing 737 fuel vent system. Source: Aeronautics guide

There is a little NACA duct at the underside of each wingtip (about a meter from the tip) in the surge tank. That ensures a positive pressure in the surge tank and through the vent channels in the fuel tanks. This help the fuel pumps, reduces evaporation of the fuel and prevents a vacuum when the fuel is being used.

source: www.b737.org.uk

If the wing tanks are overfilled, this is where the fuel will come out.

source: the aviation forum: user Keithnewsome

During the take-off the fuel tanks are changing their shape a little bit because the wing is flexing up. This may slightly reduce the volume of the tanks so if they are fully filled you will see a fuel trail spilling from the fuel vents at take-off.

Another situation where this may occur is at zero-gravity. I have seen this many times during parabolic flights with a Cessna Citation. At zero gravity the fuel will start to fly around in the tank and it will find its way to the exit (the vents at the wing tip) resulting in an impressive cloud of fuel from the wingtips. Whilst it looks like a big cloud, it is actually very little fuel that is lost.

In the video, you see the fuel trail starting below the wing (at 1:28), a couple of seconds into the 0-G part of the flight.


Do pilots have separate volume knobs on the radio panel? I have about two hours in a Cessna 172 so my instructor always managed the radio for me. I found it too loud at some times and too quiet at others. Can I tweak mine without bothering him? I forgot to ask last time. Is this the same for most / all planes or does it vary a lot?

Some modern audio panels allow for independent volume control for pilot (left seat), co-pilot (right seat) and passengers.

For example, a popular panel, the Garmin 340 has controls on each side of the panel, left for Pilot, right for Co-pilot:

Another popular panel, the PS Engineering PMA-series only separates out the Crew from the Passengers. In that case, you'd want to use your headset volume control (see below)

There are a lot of audio panels out there, so you'd just have to see if the one in your airplane supports independent volume controls.

Additionally, there is a difference between the intercom (in-airplane communication) and radio (airplane-to-communication frequency) volume controls. Often the panel handles the master volume (the mix of both intercom and comm) volume.  Whatever radio you're using (see below for an example using a popular GPS Nav/Comm the Garmin GNS430) will likely have a volume control for the Comm and Nav functions (the Nav - to listen to the audio broadcast from a NavAid).  In this case, I set the volume I like on the audio panel and then adjust the Radio volume after.

However, I think all (or 99%) of headsets have their own volume control, either inline on the cord or the adjustment is on the ear cup, so you can always adjust your own volume that way if the audio panel doesn't support it.

Inline and ear cup.

Related to all this is the question "what does the squelch do?"  Essentially the squelch is the volume threshold needed to activate the mic (notice how you don't have to push a button to talk within the airplane?). If set too low, the noise from the engine will continuously activate the mic, set too high and it won't pick up your voice even if yelling or with the mic close to your mouth. It is usually adjusted by either an outer ring (look at the little diagram on the Garmin 340 where it says SQ), or in the case of the GNS430, you push the volume knob in to adjust it. Other equipment, you pull the knob, so it's really a matter of getting to know your avionics!  A friend of mine once said, what you really need to know to fly a plane, is how to work the radio!


Is the number of relief pilots regulated? This article hints that the number of relief pilots isn't mandated. Wouldn't requiring more relief pilots for longer flights be safer and ethical? I personally prefer airlines that overwork their pilots less!

I'm asking more about North American and European airlines, not just Asia.

  As part of the agreement ending the strike, CAL [China Airline] pilots promised not to strike for three and a half years and the airline increased the number of pilots rostered for long haul flights. CAL now rosters three pilots on flights over eight hours, up from two pilots previously, and four pilots on flights over 12 hours, up from three pilots previously.

Pilot (and other air crew) rest time is an important factor in aviation safety. I'm not sure where you picked up that it "isn't mandated", but that is quite false. For example:

United States: 14 CFR § 91.1059 - Flight time limitations and rest requirements: One or two pilot crews.
Europe: EASA welcomes new flight time limitations rules (older article, possibly out of date)

Other aviation authorities around the world have their own regulations on how much pilots can work at once. These limits are very strongly respected and enforced.

I am not familiar with the regulations in the Asian countries referenced in the article you linked to, but I would be very surprised if they did not have similar regulations.


What are the major differences in operating the Boeing P-8 Poseidon and Kawasaki P1 in the maritime patrol aircraft role? What are the advantages and disadvantages of the P-8 Poseidon and Kawasaki P1 in the maritime patrol aircraft role? They were made for the same role, but they are different. The P-8 is something like converted from a civilian design while the P-1 is military-purpose built. What does that mean? What does the different number of engines mean for missions undertaken by these aircrafts?

P-8 Posiedon (left) and Kawasaki P-1 (right)

(source)

Both the aircraft were designed as replacements for the Lockheed P3C Orion when the P7 was cancelled. While the USN decided to convert a civilian aicraft (as is the norm for most MPA), the Japanese decided to design theirs from scratch (the aircraft was supposed to share a number of items with Kawasaki C2, which given the wildly different mission requirements, didn't go very well). Almost all the differences between the two aircraft, which share a number of similarities resulted from this differing approaches to design.

The P8 was derived from 737, a commercial airliner, which means that it is optimized for high speed, high altitude flight. Previosly, the MPA were optimised for low altitude operations. The P8, on the other hand has (relatively) highly swept wings with raked wingtips, optimized for high altitude cruise. This means the development of modified operational procedures for this aircraft.

Image from ainonline.com

The P1, on te other hand, is purpose built to be a more or less a one-to-one replacement for the P3C, optimised for low altitude operation with strnthened structure. The wings are swept less and the wing area is relatively more compared to the P8.

Image from battlemachines.files

Operating the aircraft at high altitudes instead of lower ones also means that the operating principles are different. It is the main reason for the P8 not having the Magnetic Anamoly Detector (MAD), which was available in P3C (as well as P1, in the long boom in the tail). Last heard, UAVs are being developed with MADs to overcome this issue.
The P1 has larger windshields (which makes sense, as the crew would be able to scan better for ships at lower altitudes) and more hardpoints compared to the P8.
The P8 has only two engines compared to the four of P1, a significant difference. For aircraft operated in long stretches over areas without airfields, this could be a real issue. While so far no issues have been encountered in this regard, the loss of an engine in a P8 is basically a mission kill, which is not an issue with the P1.
The from-the-scratch development of the P1 alos has enabled the use of fly-by-light controls, which is a first for operational aircraft, allowing for lighter wiring and lesser interference.
One significant advantage of the P8 over P1 is that being based on one of the most successful and widely operated aircraft in history, spares and support will not be a big issue.


Are records of certificate actions available? Are there any online records that may indicate why a specific DPE may have lost qualifications recently?

Due to privacy concerns, certificate actions are not made publicly available without a formal request, and have to be made via an acceptable means.

The FAA has a document titled Information Provided by PRIA, FOIA, and the Privacy Act which goes into details about how information can be requested and what they will provide:

PRIA is basically a request made by a hiring air carrier, so you wouldn't be able to do that.
FOIA is the Freedom of Information Act, and the above document states:

  Through FOIA, ANY enforcement action, whether still open or fully
  adjudicated and closed, can be reported.

The Privacy Act allows you to request your own records, or a third party company may request records, so neither of these would apply in your case either.


Why cruise at 7000' in an A319? I was on a flight from Philadelphia (KPHL) to Boston (KBOS), after some delay and some change of route due to weather, the captain announced that we will be cruising at 7000' due to delays in the area.

The history of the flight is here: https://flightaware.com/live/flight/AAL2606/history/20190618/2235Z/KPHL/KBOS

My question is two fold:

Why cruise so low with such an aircraft (A319)?
What is the impact on fuel consumption, knowing that we were also slower?

The only reason for your flight to operate at such low altitude is because it is cheaper for them to do so.

As you said it is due to weather, other route/altitude may not be available. They can cancel the flight but that is likely to be costly. They may have to find accomodation for you and crew until they can put you to the next flight. Sub-optimal flight maybe better than no flight in this case.
They may need that aircraft at that location the next day. If they choose to cancel your flight today, they will have to find a way to have this aircraft or another aircraft to fill in for the required flight the next day. They might as well fly a slightly more expensive flight at lower altitude rather than fly an empty plane to Boston.
It is possible for them to wait for weather to improve but there is an issue of crew working hour. A pilot cannot work more than 8 hours in a day without provision for additional crew. They may approach that limit and the wait for weather to improve might means the airline has to provide another crew for the flight and might mess up crew schedule for the next few days.

So for the airline, in this case, flying lower and slower maybe a better option for them. Hence higher fuel comsumption is better than no flight.


On how many routes an aircraft is used on a typical day? I wonder how an commercial aircraft used to transport passengers is used on a typical day. I imagine several scenarii, but I cannot figure out if they are right:

take off in the morning from the company's hub to an airport and then get back and begin again all day long, possibly with a changing the crew when turning at the company's hub
from the company's hub, begin the day with a round trip to an airport A, then performing a round trip to from the hub to an airport B, and continuing with other airport until the end of the day
a triangular shape: a one-way leg from the hub to an airport A, then another leg from the airport A to an airport B, and then another from B to the hub, and continuing until the end of the day. A derivative could be the same with more airports (hub --> A --> B --> C --> D --> hub)
a long multi-leg route in one direction and then back (eg. A --> B --> C --> D --> C --> B --> A)

Actually, a commercial airliner can do almost any set of legs, assuming those are technically possible (range/payload/laws like ETOPS...) But the main fact that make it possible is demand. If you run an airline, you won't make routes that don't have demand to make profit.

Aviation is a complex world. To make profit, you have to consider a massive load of parameters. You can't for example position complete set of crew in every city/airport hotel of your airline routes then decide to create fantasy flights "a la carte". Crews can't fly continuously aswell, so you can't put crew in a 737 and make them non-stop flights around the country an entire week.

One main thing you have to keep in mind : It's not one or several persons who decide "I want to build an airline with X aircraft on Y routes". It's one A-B route that decide how many passengers are available on, then, an airline has the opportunity to operate that route (and struggle to negociate all the authorizations)

Here are some hints about how airliners deals with their environment around the world :

What kind of flights does the airliner, and what airframes does it have in its fleet ?

An airliner can start with one single aircraft, says a DHC6 Twin Otter, and makes regular flights between two airports in the middle of the ocean. You can have 10, 15, maybe 20 round trip a day, some well after sunset.
An airliner can have half a dozen ATR or Dash 8, and a set of routes with the proper demand. You can have routes like hub-A-hub, hub-B-hub, when the demand is enough to make each flight profitable. Sometimes, you can't have enough passenger a day on each route, so the airliner makes hub-A-B-C-D-hub the day one, then hub-D-C-B-A-hub on day two, and cycle the sets...
An airliner with dozens of (the same) aircraft (737 or A32x) can either have the same round trip hub-X-hub destinations every day, several times a day, airlines like Air France, Southwest, Lufthansa, Air China... or the same fleet, but much more destinations operated two or three times a week : hub-A-B-hub, hub-C-D-E-hub, hub-F-G-H-nightstop-G-F-hub... like Angola Airlines (domestic and regional)
Long range flights (7 hours or more) requires the appropriate aircraft. If your airline can buy/lease such an airliner, the route hub-destination-hub can be operated in the limits of the demand. When the demand is enough to fill the plane along the week, then go ahead. Otherwise, the airline has to decide wether a) leave the plane on the tarmac, b) find a nearby complementary route : hub-A-B-hub, hub-B-A-hub, c) use a smaller and cheaper aircraft (if the crew is qualified on) d) combine destination A with a complementary destination B that fills schedules along the week (or bi-week) hub-A-hub-B-hub, e) replace the route with one better, f) negociate with one or several airliners to sell seats to them to fill the aircraft, g) negociate with one or several airliners operating on the destination airport to take advantage of the hubbing : make your airline land at the destination during rush hours.
Very long range flights can't be operated every day with one single aircraft. And very long range flights are a niche : the hours spent in that closed tube discourage passengers from taking such flights. And very long range flights are a hell to schedule : the aircraft does 3 or 4 flights a week, and stays on the tarmac the rest of the time.

The size of the airline :

If your airline is a big one, like British Airways or Japan Airlines or United, your reputation and historical operation is enough to get demand on most usual routes (and your staff has the expertise to select profitable ones) Most of your flights will be the type "hub-X-hub", either domestic, regional, or international.
If your airline is above average (like Kenya Airways, Aeromexico, Air India) you'll have a mix of "hub-X-hub" flights and some complementary legs to fix schedules and aircraft operation ratio : hub-A-B(-C)-Hub
If your airline is below average (Blue Panorama, Air Kazakstan, Belavia) chances are great to have charter flights, multiple flight shifts.. Timetables greatly vary from one year to another.
Small airlines like Air Austral, Republic Express (Indonesia), Insel Air will have historical regular flights, but most of them will be of type "hub-A-B-hub" and/or "hub-A-C-E-C-B-hub". Timetables also vary from one year to another, but at a less rate than above because the airline don't have enough aircraft to think of new or better routes to operate, as the ones available cannot be closed or replaced.

The region of operation - the airport statistics (passenger volume per year) :

There are regions of high frequency of flights : Western Europe, United States, Japan, South-East Asia, Eastern Australia, the Dubai-Europe axis... In those regions, you have several hundreds of round trip routes that can be operated ten times a day using a Boeing 747. Cheap flights, historical demand, dynamic business. You can operate flights of type "hub-destination-hub".
There are regions with much less traffic, but enought for one airline to operate the simpliest flights hub-dest-hub. However, once another airline or more decide to compete on the same route, everyone is forced to reconsider the way it operates their fleet.
You also have regions in the world, especially in Africa and some non-democratic countries out there, where only one airline is allowed to operate a given route. Usually, those airlines don't care about competition, as the state/country itself protect them. Ticket prices on those routes are unusually high, because they can. So the demand on those routes NEVER take off, thus, making the flights on them the same along the years. You'll have destinations operated once a week (if not once a month) You'll have very small airlines and you don't understand why, having the monopoly on the network, they are not able to grow, grow the traffic, and propose better schedules for custommers than the absurd routes and departure/arrival times. Simple : they simply don't care.

Night Flights - jet lag.

You can't just make an aircraft take off, and land when you want. A custommer usually don't want to land at an airport at 3AM.
An airline should avoid boarding passengers at 5:30AM, just because if you board at that time, you've waken up at 3:00AM, failed to take a breakfast, almost forgot your papers, arrives at the airport hungry and angry...
jet lag : If you take off from San Francisco at 09:00PM, going to New York, you'll land at 06:25AM. It's okay ! But if you take off at 05:15PM, you'll land at 03:40AM. You haven't slept well.. Perhaps at NY, it's okay to land so early in the morning, but try this in Charles de Gaulle and you'll see how boring (or expensive) it will be. Jet lag is an important factor for international flights. When the airline can't have the slots to land at a proper time at the destination airport, it should think of alternate flights to do, or negociate the opening of an intermediate destination of interest before operating the projected flight, this creating legs like "hub-alternal-hub-destination-hub" or "hub-alternate1-alternate2-destination-hub" or "hub-alternate-destination-alternate-hub". Airlines like Air Madagascar does this. Landing at an airport late in the night is another reason of nightstops. This is common with regional jets (737-ERJ-A32x...)

Aircraft operated by several airlines.

Sometimes, you'll have aircraft operated by the owner some days in a week, and by another operator the remaining time. Take for example InterAir of South Africa. The aircraft is based at Johannesburg, and operates InterAir flights from and to JNB. But on Wednesday and Friday morning, the aircraft takes off from JNB as an InterAir flight, to Cotonou, and from there, it operates for AeroBenin to several destination in central Africa. The aircraft returns from Cotonou the Thursday and Saturday afternoon as regular InterAir flight. So don't be surprised to find a flight from JNB to Cotonou Wed and Fri morning, and their returning legs on Thu and Sat afternoon. That's common in Africa, South America and Asia. Many airlines like Blue Panorama, Lot Polish, EgyptAir (...) lend some of their aircraft to smaller airlines in the world on a week basis like this. The smaller airlines operate them on routes like "hub-A-B-C-B-A-hub" to use the aircraft as long as possible in the few hours/days.

So, those are only hints to understand how routes as selected and arranged. To enumerate all possible schemes, even a book won't suffice.

It is possible to have much more aircraft than routes (when you have enough demand) or the inverse. An aircraft on the ground is an aircraft that costs money for nothing; so "hub-X-hub" flights are rarely the best way to operate an aircraft. Key words are "demand", "costs", "profit". To get factual datas to calculate those, you'll need parameters like aircraft performance, airframe availability, route statistics, crew/maintainance possibilities, security/safety, regulations/laws/authorizations... then compare and negociate the opening of the most profitable route with the less risks with the appropriate aircraft.

Side note : I'm no expert. I'm just an aviation enthusiast, mostly airliners of the 1960-today era.


Can the 787 mini navigation display be controlled independently from the ND? Some aircraft, e.g., the Boeing 787 have the option to display a "Mini Navigation Display" on the left Outboard Display Unit, right under the Primary Flight Display:

(image source)

Is the information shown there a copy of the "normal" Navigation Display on the Inboard Display Unit (possibly with a limited set of information?), or can it be fully customized by the pilot independently of the other ND? (I'm not talking differences between left and right side PFDs/NDs, but I'm talking only one side, e.g. the left side only).

With "copy of normal ND" I specifically mean ALL updates to the ND via the EFIS control panel are reflected on both the ND and the mini ND. This would include wx, airports, range, modes (plan, arc, rose), etc.

In case of independent controls, how can the pilot customize the mini ND?

The MiniMap is not an option, it's there as standard.

It's fixed at 20-miles range; the optional items are Wxr, Terrain and Traffic. The classic STA, WPT and ARPT from the ND are not available.

The MiniMap shows ADF needles, whereas the ND shows VOR needles.

The MiniMap looks like a development of the previous compass-rose at the bottom of the PFD, but it's mostly of little practical benefit. The major use of the MiniMap is to show Terrain while having Wxr on the ND, a dual-view that wasn't possible before.


What is this high wing, single engine aircraft? I think it might be a Douglas aircraft.

Indeed a Douglas aircraft, namely the O-43, an improved version of the O-31 (longer wing and a new engine) which was Douglas's first straight-wing monoplane.

The O-43 was in turn developed into the O-46


Have pilots encountered a UFO, and what to do if you have? Have pilots ever encountered a UFO? What guidelines, if any, are in place for times when this happens?

Pilots do encounter UFOs all the time. I just want to emphasize that UFO means "Unidentified Flying Object" - something which is flying, and which the pilot cannot identify. It does not mean an alien craft.

The guidelines for pilots are as follows (AIM 7-6-4):

  7-6-4. Unidentified Flying Object (UFO) Reports

  a. Persons wanting to report UFO/unexplained phenomena activity should contact a UFO/unexplained phenomena reporting data collection center, such as Bigelow Aerospace Advanced Space Studies (BAASS) (voice: 1-877-979-7444 or e-mail: Reporting@baass.org), the National UFO Reporting Center, etc.

  b. If concern is expressed that life or property might be endangered, report the activity to the local law enforcement department.

Air traffic controllers have the following guidance under FAA Order 7110.65 section 9-8-1:

  9-8-1. GENERAL

  a. Persons wanting to report UFO/unexplained phenomena activity should contact a UFO/ unexplained phenomena reporting data collection center, such  the National UFO Reporting Center, etc.

  b. If concern is expressed that life or property might be endangered, report the activity to the local law enforcement department.

The question "Was it of the E.T. kind" is beyond the scope of this site. This subject is, let's just say, suitably covered by other sites on the Internet at large.

One notable example of a UFO report is the 2006 O'Hare UFO sighting. For other examples, a Google search for "pilot UFO anecdotes" offers some decent results. "ATC UFO report" even links to some recordings of pilot UFO reports to ATC.

Some objects commonly reported (genuinely) as UFOs are spacecraft, fast or high-flying military aircraft like the U-2 or the SR-71 when it was in service, rocket launches, weather balloons, kites, errant helium balloons from kids' birthday parties, flocks of birds, con trails, and lightning storms. Any of these and more can easily look, under the right circumstances, to a pilot like a "UFO."

The closest experience I've had in my flying history to a "UFO" happened at night, during a landing approach in the midwest U.S. I was on a downwind leg when a very bright light appeared above me in the center of the windscreen, and rapidly moved downward toward the horizon. It scared me half to death; my instinctual thought was that it was the landing light of another plane descending on top of me. It turned out to be a meteorite. It only took me a second or two to figure it out, but boy did it get my adrenaline up! There was no need to report it though.

Culturally, pilots are generally apprehensive about reporting UFOs, out of fear of sounding like a lunatic or unhinged conspiracy theorist and being laughed at. Nonetheless, reports are not uncommon.


Are there differences in air traffic services between western nations? What are the major differences (if any) between the air traffic control service in Europe vs. USA vs. Canada?

One of the big differences between regions is how aircraft operators pay for the service. In the US, the FAA is funded by taxpayers and fuel levies. In New Zealand (for example), aircraft operators are billed for use of air traffic control services. I don't know what the billing situation is in Europe.


What are the most challenging taxi manoeuvres that a typical commercial airline pilot must execute? I am currently involved in a University level modelling excercise which looks to investigate the handling qualities of a novel nose wheel steering system.

As part of this study, I am interested in understanding what are the most challenging taxi manoeuvres that a commercial airline pilot would typically execute, both regularly, or in special circumstances.

Some specifics for the question:

I am primarily interested in answers from pilots of Single Aisle
sized airliners (A320 family, 737 series, etc.), although general
cases are also welcome.
I am interested in the kinds of manoeuvres which place the highest demand on the NWS system in terms of responsiveness, max rate demand, etc.

"Most challenging" is a matter of opinion, but if I were to pick, it is probably the 180 degree turn.

The purpose of the maneuver is to turn the aircraft around and face the opposite direction. The technique is to position the aircraft to one side of the runway (taxiways are generally too narrow for this), then apply maximum steering angle, minimum thrust as well as differential braking (i.e. braking on the inner set of wheels only).

The challenge is that the nose wheel, outer set of wheels, outer wingtip and the tail each have their own turning radius. It is made even trickier when the nose wheel is a good 20~30 feet behind the cockpit. The pilots will be above the runway grass while the nose wheel is still on the pavement.

This maneuver is challenging enough that most aircraft manuals I've seen (e.g. B737, B777, A320) dedicate a good 10~20 pages just for this. Here is an example diagram for the B737-600:

B737 FCOM Volume 2, Section 1.10.7

This maneuver is mostly executed on small airports where there is no taxiway connecting to the end of the runway. For example, the only taxiway connection to the runway might be at the runway's middle length. A plane that wishes to use the full runway length to takeoff will have to turn onto the runway, taxi down half its length to the end, then execute a 180. On large airports this is rarely an issue, although a 180 might be useful when part of the taxiway / runway is blocked due to an incident.


Why does setting the Legacy 600's transponder to standby mode also deactivate its TCAS? In 2006, a 737 operating as Gol Transportes Aéreos Flight 1907 crashed following a collision with a Legacy 600 business jet; the Legacy's transponder proved to have been in standby mode1 at the time of the collision (due either to a transponder malfunction or to the crew having inadvertently switched it into standby mode), which, obviously, prevented the 737's TCAS from seeing the Legacy and sounding an alarm.

However, setting the Legacy's transponder to standby mode also, apparently, deactivated its own TCAS:

  Considering, according to declarations, that the N600XL pilots did not perceive that the transponder had stopped transmitting and that, as a result, the TCAS was inoperative...  [CENIPA report, page 83.]

This is also, apparently, the result should the transponder fail outright:

  In case there is a Transponder failure, the operation mode and code selected are replaced by dashes in the RMU. An orange message “TCAS FAIL” will appear on both Primary Flight Displays (PFD) precisely in front of the visual field of view of both pilots, as shown by the pictures bellow [sic].  [CENIPA report, page 92.]

I'm not seeing the rationale for this; even if the aircraft's transponder fails or is switched off, there doesn't seem to be any inherent reason why this should require also deactivating the TCAS.  Even if the transponder can't, or won't, transmit, the TCAS should still be able to pick up signals from other aircraft's transponders, allowing it to continue to function, albeit in a receive-only mode.

So why does the Legacy 600's TCAS cease to function if the transponder is standing by or inoperative?

1: In standby mode, the transponder does not respond to any interrogation signals, either from the ground or from other aircraft.

At least under FAA regulations the TCAS system goes into standby (by design) if the transponder fails

  A Mode S transponder is required to be installed and operational for
  TCAS II to be operational. If the Mode S transponder fails, the TCAS
  Performance Monitor will detect this failure and automatically place
  TCAS into Standby. The Mode S transponder performs the normal
  functions to support the ground-based ATC system and can work with
  either an ATCRBS or a Mode S ground sensor. The Mode S transponder is
  also used to provide air-to-air data exchange between TCAS-equipped
  aircraft so that coordinated, complementary RAs can be issued when
  required.

TCAS II systems get their altitude information from the transponder, which is a vital parameter to the system working.

(source)

All modes also require a functioning Mode S transponder

  Stand-by: Power is applied to the TCAS Processor and the Mode S transponder, but TCAS does not issue any interrogations and the
  transponder will reply to only discrete interrogations. The
  transponder still transmits squitters. Note: If the aircraft is on the
  ground and transmitting extended squitters, it is not required to
  transmit short (acquisition) squitters.
  Transponder: The Mode S transponder is fully operational and will reply to all appropriate ground and TCAS interrogations. TCAS
  remains in Stand-by.
  TA Only: The Mode S transponder is fully operational. TCAS will operate normally and issue the appropriate interrogations and perform
  all tracking functions However, TCAS will only issue TAs; RAs will be
  inhibited.
  Automatic or TA/RA: The Mode S transponder is fully operational. TCAS will operate normally and issue the appropriate
  interrogations and perform all tracking functions. TCAS will issue TAs
  and RAs when appropriate.

Strictly speaking all of this is only applicable to TCAS II systems but based on the noted case and my reading of the accident report it appears TCAS II was the system in use in this case.


What would happen if ultralights had mountain bike style treaded tires? What would happen if ultralights had off road treaded tires?

Mountain bike tires are made for going off road through mud, etc.  They have voids between the tire lugs to clear mud etc.

Why not off road going airplanes?

I assume the reason is, the lugs would catch air and start the tire spinning during flight?

Is this correct?

Or is it just a drag thing?

Mountain bike tread is meant to sink into the mud in an attempt to gain traction on firmer ground beneath the mud.  A plane generally doesn't want to sink into the ground (even during braking), if it sinks too far during landing or take-off, the airplane is more likely to catch the forward gear and flip/strike the prop.

Bush plane tires are designed to land on soft fields.  The difference between mountain bike tires and bush plane tires is that the high surface area of the bush plane tires attempt to "float" on top of the soft ground rather than dig into it:


What's this prominience in the B737? I have recovered some spotting pictures that I made long ago and I came to realize an upper prominence in the fuselage of this Norwegian Boeing 737. I don't remember to have seen it in other 737s.

Does anyone know what is it and its purpose?

It's a SATCOM (Satellite COMmunication) antenna. It has several purposes, one of them is internet connection for the passengers.

There are different types and configurations. On some aircraft the antenna is in the front, on some it's in the back, some have two.

(image from http://www.b737.org.uk/latest-2016-04-06.htm)


When does an instrument approach "begin" per §135.225(a) §135.225(a) states that, "...no pilot may begin an instrument approach procedure to an airport unless—
(1) That airport has a weather reporting facility operated by the U.S. National Weather Service, a source approved by U.S. National Weather Service, or a source approved by the Administrator..."

Assuming that a part 135 pilot is operating to an airport where the weather reporting is out of service, and the pilot is not conducting eligible on-demand in accordance with §135.225(b). What portion of an IAP (if any), can be flown in this case without violating the intent? Is the IAP considered to "begin" at the IAF, IF or, for the intent of this regulation, at the FAF? Or, does it begin at the point ATC says, "cleared for the approach?" In a case such as this, the 135 pilot is needing a descent to VFR weather, since an IFR arrival (including visual or contact approach) is not authorized. Being able to descend to a the initial or intermediate segment altitude would obviously be an advantage.

If a local (or designated facility) altimeter setting is not available, terrain clearance would not be guaranteed when descending to the initial and intermediate altitudes. In that case I believe that ATC could not give a clearance for descent to those altitudes.

Beginning an instrument approach would mean being established on any segment of that approach, whether the initial, intermediate, or final approach segments, and they have received ATC clearance to do so.


How to become a expert in Flight Operations Business? (Flight Dispatch, Weight and Balance etc.. ) I am working in IT industry relavent to airline operations (like flight dispatch related products).I would like to enhance my knowledge in Flight operations area.

What are the trainings (IATA/others) or courses  recommended for flight operations related business process?

It depends on where you are located and what country you are located in as to what kind of license will be beneficial to you. If you are in the United States, obtaining a FAA dispatch license is a common route to working in flight operations. There are community college programs to prepare you to take the exams. The benefit to the FAA license is it never expires. In other countries there are similar licenses you can obtain. I would be cautious to IATA programs mainly due to the price and many are geared towards existing professionals in the industry.


Double deck vs wide body airliner, why would anyone build a double deck one? I don't understand why double deck aircraft (or multiple decks in general) are a good idea. They must be, because there is a significant amount of them.

But given a cross area, which should roughly correlate to the drag of the body, wouldn't a wider cross area provide some additional lift for "free" as compared to having higher lift wings instead?

Why don't we see very wide airliners where the body provides a siginificant amount of lift?

Problems with just making the fuselages wider:

With the wing or main gear supporting the center of the fuselage, the front and back are cantilevered. Think of a hard landing or 2.5G pull up. The most effective structure to support bending is tall, with material on top and bottom (like an I-beam). A flat fuselage would have to be heavier to provide the same strength.

Depending on how you shape it, you're trading wasted space above and below the cabin for having an efficient pressure vessel shape. If you want to fit standard cargo containers below, that constrains your options.

Although you may get some amount of lift from the fuselage it will probably still push the wings and engines outwards by some amount, creating issues with gate width limitations.

In order to meet evacuation requirements, there would need to be more doors or at least emergency exits for a given length. That could mean more cross aisles and less room for seats. It may also be easier to access multiple doors for passenger to board/disembark if they are on different levels than the same level.

Lower ratio of windows to seats. Less natural light. People like window seats.


Does Daylight Saving Time affect local airspace? Only some countries use Daylight Saving Time. In Canada, some provinces use and don't use DST (such as Saskatchewan). However, in remote and local regions where this is not observed, what would happen?

What happens when areas that do not observe DST are controlled by areas that do. (Cleveland controls parts of Southern Ontario). How does this affect local airspace? Does it affect global airspace as well? What are the safety implications? How does it affect Air Traffic Controllers operating these different spaces?

Aviation always uses UTC time. This is from the FAA's AIM, but other countries do the same for obvious reasons:

  4-2-12. Time

  a. FAA uses Coordinated Universal Time (UTC) for all operations. The
  word "local" or the time zone equivalent must be used to denote local
  when local time is given during radio and telephone communications.
  The term "Zulu" may be used to denote UTC.

This question covers in much more detail why UTC is used in preference to GMT, and this question explains why pilots need to know the time in the first place, at least under IFR (which applies to almost all airline flights).


Why do flight attendants continue to stand, when the seatbelt sign is on? Especially during turbulence, I notice that passengers are warned to sit and fasten seatbelts, but flight attendants continue to serve only cold beverages (since the overflow, slosh, spill of hot beverages would be dangerous), stand, walk, and work. Why? It appears unfair for flight attendants to suffer any more risk and danger, even if the turbulence is minor, than passengers.

I worked as a flight attendant for several years and I am still employed within the industry but in a different capacity, so I know a thing or two about this topic.

Flight Attendants (FAs) are strictly required to be seated during take-off and landings only and usually not during descent or climb, unlike passengers who are usually required to be seated and buckled. Then it depends on the local rules for how long they are supposed to stay there. In some airlines, the FAs must sit as long as the seatbelt sign is lit, while in others they can move about once the gears are up (you can hear this easily, as they make a loud sound when they are retracted). Other airlines might state FAs can move once the plane reaches a certain altitude and/or are given some sort of sign from the cockpit.

There is not one type of turbulence, but various classifications. Some of them are just light (small bounciness) and some are dangerous and can injure (or kill) people who are not seated and buckled. It is usually cabin crew who are the victims (I have personally been through this kind of turbulence).

Usually, pilots will, during the pre-flight briefing, brief the cabin crew of any expected turbulence and will usually say something like: "seatbelts are for everybody" or "seatbelts are for passengers". If things during the flight end up different from the forecast that was given to the pilots prior to the flight, the pilots will call the cabin crew and inform them. They will tell the cabin crew whether to continue the service because it is a light turbulence, they may suggest only to serve cold beverages, or tell the FAs to sit tight and secure everything if approaching severe turbulence.

This is basically the "secret" behind it. There is no magical training given to cabin crew on how to defeat the laws of physics and stand balanced while in turbulence; it is just the word from the pilots as they are the most knowledgeable about the weather conditions. The crew are only trained on types of turbulence and on how to secure the cabin and service carts quickly in case of sudden severe turbulence that was not detected in advance. In that case, they are told to hang on to anything and secure themselves.

Passengers, on the other hand, are required to be seated and buckled during all phases of the flight except cruise and when there is no turbulence. This is simply due to liability and not to add more complication in these critical times.


Why is the front part of the engine not painted? The engines are always painted a certain colour but the front part is always grey.

Source

And here on the XWB:

Source

Why is it that?

The engine inlet lip is bare metal to facilitate anti-icing. The area is heated from within using hot engine bleed air.

This partial schematic (from Boeing AERO QTR_01.12) shows the engine anti-ice valve, which controls the air supply to the inlet lip:

Interesting side note: Even the 787 "no-bleed" system architecture uses bleed air for engine anti-ice.


How to record Intercom / ATC in a small aircraft like a Piper Archer? For making videos it would be nice to have some more sound than the engine sound recorded by my GoPro. What ideas do you have to record the aircraft intercom? It won't be a problem for me to have two files (an audio and a video file).

Edit: I'm looking for a good sound quality comparable with that which you will have while sitting in the aircraft listening to the intercom.

For the GoPro specifically there are audio recording cables you can buy which connect to your intercom jack and provide a pass-thru connection for your headset.
There are other cable options available to support recording on different devices (e.g. iPhone/Android phones and tablets).

As is often the case with "aviation" accessories these can be somewhat expensive, but they're also pretty reliable drop-in solutions. As mah noted if you have a spare headset jack you're not using plugging into that can be much cheaper and just as effective.


Which light aircraft are known to have a quiet cockpit? Are some light aircraft known as being significantly quieter in the cockpit than others ? How quiet might the quietest light aircraft be from the inside ?

At least ten years ago I was reading an aviation magazine and there was an article about someone who had gone all out to make their aircraft cockpit as quiet as possible. I can't remember the details but they'd made a whole lot of modifications with sound reduction in mind.

Ever since then I've wondered: are some light aircraft really noticeably quieter than others (and do they get sold on the basis of them being quieter) and is modding your aircraft to make it quieter a common thing ?

(I am of course referring to closed cockpit aircraft, I appreciate a Gypsy Moth would inevitably be quite noisy !).

I assume that you're asking about piston engine light aircraft, so we can ignore gliders and electric engines for now.

The basic point is that they're all loud. One study compared a Cessna 172 (single engine) and a Piper Seminole (twin engine) and found that the average cabin noise was around 86 decibels, with no huge difference between the two aircraft. There's more analysis of a Seminole here. The FAA says that a light aircraft cabin is in the range of 70-90dB and this Cirrus owner measured 92-98dB in different Cirrus models. OSHA in the US requires ear protection and other measures for workers if the noise in their environment is 85dB or more.

Since decibels are on a logarithmic scale, the difference between 86dB and 98dB is large. But I searched a few aviation forums and there's very little discussion of cabin noise in light singles apart from a few subjective remarks. I couldn't find any good sources that said one aircraft type is well known as being noisier or quieter than average. The only consistent comment is that helicopters are louder than fixed-wing aircraft, which is also shown in the FAA document linked above.

Having said that, there are quite a few articles online about soundproofing aircraft in different ways. This one quotes the example of a jet:

  Aero Sound Shield is currently soundproofing a particularly large
  corporate jet - a converted McDonnell-Douglas MD-87 - for a Las Vegas
  hotel owner who is almost totally blind and who has compensated by
  developing extremely sensitive hearing. "He wants a 60-dB airplane,
  which is quieter than a Lexus," Nelson points out.

But the same article makes the point that modifying any aircraft to add soundproofing increases the weight to a point that makes the aircraft much less useful:

  Unfortunately, your airplane and mine can't accept the mass and weight
  of MD-87 measures. "I rode one time in a Piper Arrow that was very
  quiet," Nelson recalls, "but it was completely lead-lined. It could
  carry two people and half a load of fuel. That was fine for that guy,
  because that's all he ever wanted to carry, but it wasn't very
  practical."

Furthermore, it's worth remembering that modern noise-cancelling headsets are very good so the problem of noise (as opposed to vibration, which is also a factor for fatigue and health) has been more or less solved for most people. Even if you spend $1000 or more on a high-end ANR headset, that's a minor cost compared to altering the aircraft structure or materials and you still have full performance and useful load. I guess that for most GA pilots that's the decisive factor.


What's is the difference among ECL, CFL, RFL, TFL messages in ATM? These are several messages to provide a change level during air navigation. Some are sent or requested by the pilot, others by the air traffic controllers, etc. There are subtle differences. Could anybody provide an explanation to show their differences?

Related question: What is the difference between RFL and ECL in Air Traffic Control?

In Air Traffic Control their is quite a few acronyms for levels at various stages in the flight. I am not sure what you meant by messages, or more importantly which messages, so I have kept the answer a little broader.

RFL

Requested Flight Level

The level that is requested in the flight plan before the flight. There can be multiple RFLs in a flight plan. Each time the aircraft wants to cruise at a different level, in the flight plan, an amended RFL is added.

The Pilot may also request an amended RFL mid flight but the RFL is not mentioned at the time just the request for a different level.

Speedbird 1 Request Climb FL360

CFL

Cleared Flight Level

This is the level that the aircraft is currently cleared at or cleared to.

This can be a level on the way to the RFL used as paperstop level for separation (a level the pilot is never expected to maintain but provides separation until conflict no longer exists);
The RFL when the aircraft is maintaining; or
Any other level that the aircraft is cleared to.

ECL

Enroute Cruising Level

Stole part of this one from the question: What is the difference between RFL and ECL in Air Traffic Control?, Thanks GgD for the resource.

From the EUROCONTROL SPECIFICATION FOR TRAJECTORY PREDICTION Edition: 1.0

Page 2:

  1.5. Definitions

  Enroute Cruising Level - The level that the flight is to maintain for a significant part of the flight after reaching TOC and prior to TOD.

Page 33:

  2.3.2  Enroute Cruising Level (ECL) (3.3.2)

  Domain Knowledge: The  ECL   is  a  notional
  level  that,  in  the  absence  of  constraints,  equates  to  the
  RFL .  In  the  case  where  a  flight  is  not  permitted  to  cruise
  at  its  RFL   for  any  or  a  part  of  its  route,  due  to  the
  presence of a  strategic constraint (level limit) which applies to
  flights between the  aerodromes of  departure and destination, the ECL
  will be limited  to the level defined by the constraint. The ECL may
  also  be  changed  by  instruction from  ATC where  the flight is to
  maintain a different cruising  level, typically due to the proximity
  of a flight at the  RFL  on the same  route.   As with the  RFL ,
  the  ECL  can be changed for different  segments  of the  route  and,
  if different in  the  cruise  phase,  is  changed  to  the  XFL   on
  passing  the  sector   boundary.  The  notion  of  ECL ceases to exist
  after the final  TOD  from cruising level.

So summarising the above passages, the ECL is the level that will be maintained from top of climb until top of descent. The ECL can be the same as the RFL if the aircraft can be cleared to fly the RFL.

So if there is a conflict at the level of the RFL and the aircraft is cleared to a level below the RFL, the ECL would be that level.

When the aircraft is cleared to fly the ECL the CFL and ECL are the same. So you can get the RFL, ECL and CFL as the same level.

TFL

Personally I have never heard of this level acronym so I am unable to respond on its relationship to the others. If someone else knows I would love to know also.

Additional Level Acronyms

I am also adding the major other level acronyms for ATC into the mix so they are all together. So the answer is as complete as I can get it.

XFL

Exit Flight Level

This is the level that the aircraft is going to cross an ATC sector boundary at. There are two different ways of using the XFL around the world:

In some ANSPs (Air Navigation Service Providers) it is the level that the aircraft will be cleared at when the aircraft calls the next sector. In this case the aircraft could be on Climb or on Descent to the XFL or could be maintaining the XFL all ready. This is used so that the controller knows the CFL when the aircraft calls.
In other ANSPs is is the level that the aircraft will cross the boundary regardless of the CFL issued at the time. This one is used for trajectory calculations inside the receiving ATC system.

PRL

Pilot Reported Level

This is the level the Pilot last reported at. In Procedural Environments this is the only way there is to find out the current level of the Aircraft.

MCL

Mode Charlie Level

There can be other names and acronyms for this level but they all have the same meaning.

This is the level received by the SSR radar or by the ADSB receiver. This has the the aircraft's current level usually embeded in a message with other details. This can be used to fill in the PRL on some systems or is a complete independent system from the PRL.

Sorry I found this question so late but thought it deserved an answer anyway.


Is platinum present in a combustion chamber? Platinum group of metals (PGM) are very resistant to extreme heat. Why is platinum never mentioned in aerospace world? Is this a top secret?

To elaborate on mins comment: platinum right now is selling for around \$1000 / troy ounce, which is ~\$14,500 / pound.  Nickel is selling for around \$4 / pound and cobalt is \$25/pound. Nickel and cobalt super alloys have sufficient temperature capability for jet engine applications.  So the choice is clear. Platinum is not mentioned because it is not used.


What instructions should I give to an untrained passenger for Hand propping Cessna 172N as a pilot? Does anybody know what is the most effective way of hand propping a Cessna 172N, with a passenger who is not mechanically inclined.

So you need to give them the most easy to follow and simple instructions. Like after pulling the hand brake, and priming and opening the throttle 1/4 inch what do you tell them to do?

I would push the throttle gently in after I'd hear the engine coughing to power when hand propped, while keeping my feet on the brakes, till  engine's smooth revving and maintaining power.

But to a person that has no familiarity with the noise of the engine and does not know what to expect, what should I say.

Edit
I thought I should elaborate a bit to shed some light on what happened.

We had come back from a half a day of  hiking around the hills of Santa Ynez in the afternoon with my hiker friend. After trying to crank the ignition a couple of times, it just moaned jerking half way through a hesitant arc.

We looked around for something to use as chocks, found two rocks like 8-10inched and kind of heavy and pushed them to a locking position in front of the tires.

I set the throttle; told him not to touch it before I jump back after cranking and wave him all clear. Then he pushes the throttle by half an inch while pushing the breaks. We brought the engine back to life after a few tries.

After I felt we have a enough of prop rotation inertia I got on to the right seat and brought the RPM down. He got out and removed the rocks. Got back in and we flew back to Van Nuys.

That is crazy.  DON'T just rely on an person who's new to airplanes and only training is 5 minutes of showing them what to do, who may or may not react correctly when it springs to life, as the only thing preventing the plane from heading off somewhere while you try to dive clear.  Don't. Do. It.

Tie the tail. To something.  Anything.  Use the passenger and show them what to do and give them a careful briefing, but tie the tail down anyway.  You don't know how the passenger is going to react if things go off kilter.  And if tying the tail is simply not an option, and you have no choice because you have to leave because zombies are approaching, at least point the airplane toward some obstacle just beyond the normal turning radius, like a wire fence, for it to run into when it takes off with your passenger confused and frightened because they pushed the throttle in too much and let off the brakes when the thing jerked forward on them, with you diving for your life.

Once it's running at idle and everything is kosher, set the parking brake and you can walk back to untie it with your passenger ready to switch the ignition off if it starts to roll away.

And make sure to use the correct terminology with your assistant.  Don't say "switch on/switch off".  It's "Switch off" for ignition off, and "Contact" for ignition on (it's old fashioned sounding, but it works).

I have been personally burned by a guy who did things the usual way, when I said "switch off", then repeated "switch off" to make sure he heard it.  He thought I'd said "Switch off" then "Switch on" when I'd just said switch off twice.  I neglected to brief him on the use of the word "contact" so it was my fault in the end.  Anyway, I got a nice noisy surprise when I turned the prop over thinking ignition was off.

Hand propping is quite a dangerous operation, especially on tri-gear airplanes where you have to lean forward to do it.  I trust you yourself have been properly trained, and know things like not to hook your fingers over the blade so you don't get pulled into it if it kicks back, that sort of thing.


Would a slower and larger rotor blade be practical? Essentially a rotor is a rotating wing and the design of that wing generates lift. My question is this, why not increase the surface area of the rotor and slowdown the rotor speed. Rotor strength will also be increased. Slower rotor speeds will also reduce the turbulence created by the larger area of the rotor.
I believe that this will also increase efficiency as the reduced speed can result in smaller engines being used to do the same work.

Indeed a relatively large rotor has advantages:

Low induced velocities: less sand and bushes that are swept up by the rotor airstream.
Low autorotational rate of descent.
Low power required in the hover.

However, there are some disadvantages as well:

The size of the helicopter is less practical at landing, take-off, clearance of buildings etc.
The empty weight is higher, a very important factor in VTOL aircraft.
The hub drag is higher.

A smaller rotor will have a smaller and lighter hub and a lower overall parasitic drag: more efficient for cruising flight. There is a practical limit to blade radius of about 12 m due to static rotor droop when not spinning. From J. Gordon Leishman:

  The static droop can increase quickly for larger rotor diameters and may cause problems when starting and stopping the rotor, especially in gusty wind conditions where the low centrifugal forces on the blades may lead to "blade sailing,"causing the rotor blades to flap and flex and perhaps impact the airframe.

The rotational speed of the rotor is determined by the tip speed, and is set such that at cruise speed the advancing blade tip stays below the drag divergence Mach number. Reducing the tip speed permits a higher flight speed to be achieved.

Image source

There is a design optimum for rotor disk size, determined by weight. The weight over disk area ratio is the disk loading and the analogy with wing loading of fixed wing aircraft is very strong: a large wing area creates more drag and construction weight. The relationship between disk loading and operating weight is partly governed by the square-cube law, and a clear trend can be observed when the two parameters are plotted against each other: there is an optimum governed by weight, and the optimum is not the largest rotor diameter.


How low can a helicopter fly above a residence if the helicopter is an air ambulance landing? Two medical helicopters just located directly across the street from my home.  Their landing pad is less than 500 feet from my property.  When they land, the helicopter is only 100 to 200 feet above my roof and is causing stress cracks in my home. The noise and the fact that the downward wind from rotors is causing vibration in my walls. The pilots have many other options for directions to approach and land but use the shortest route.

What are my rights? Don't I have the right to quiet and peaceful use of my home?

After all, those helicopters are part of a business and I was here 10 years before they located in this unzoned area of Alabama.

Talk to a lawyer.
Disclaimer: I am not a lawyer, and this is not legal advice.
The fact of the matter is, regardless of whether or not they've got FAA clearance to operate the way they do, they're causing physical damage to your property. As such, I would recommend talking to a lawyer about what your legal options are. While suing them for damages would definitely be a step you could take, a lawyer would be able to advise you on how best to navigate the process leading up to that, potentially involving things like Cease and Desist letters or negotiated settlements with the company in question.
Since you're from America, it's also entirely possible that your state might simply seize your house with Eminent Domain and give you a token payment for its "fair market value", since the construction and operation of a hospital with medical helicopters clearly falls within its remit. As a result, I would recommend to be prepared to start looking for a new house should you begin a dispute with them.