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Do pilots have to stop at the hold position of the takeoff runway? Or in other words, is the takeoff clearance ever given (implicitly or explicitly) before the aircraft reaches the hold position, so that the pilot can keep rolling through the hold line and to the takeoff roll? <Q> Typical clearances given before depart...	You COULD request takeoff clearance as you are approaching the runway, obviating the need to come to a stop, but a towered airport is usually busy enough that the controller will want to see you at the line, ready to go, before giving you the runway. No, there is no mandatory stop.
Do fighter jets have an auxiliary power unit? Do fighter jets have an auxiliary power unit? If they don't, then how does the propulsion/ignition process start in the engine? <Q> Most current fighters do. <S> A notable exception is the F-16. <S> The F-16 has a "jet fuel starter" (JFS), which is a small jet turbine sta...	The F-16 starts the engine using the Jet Fuel Starter which receives its initial pressure to spin from the JFS/Brake Accumulator bottle which is a dual-purpose system as the name denotes. It all depends on the airframe you’re talking about.
How is fuel planning done for a VFR flight that involves multiple full stops? Doing first cross country flight plan with several stops along the way. What is the general rule of thumb for calculating time, fuel, etc. for a mid trip landing? I've done conceptual flight plans with checkpoints etc, but not actual stops....	You have to have enough fuel on board to reach your planned reserve airport if you arrive at your destination and find that it's closed (e.g. because of an accident).
What are the relations between stability, controllability and maneuverability? As preparation for my CFI checkride I have been trying to understand aerodynamics very well. One of the things I’m struggling with is stability If I have a stable aircraft, this means is less controllable and less maneuverable, right? Do ...	a plane exhibits "neutral" stability if, upon a control input from the pilot or a gust perturbation, the plane will not right itself if the pilot takes his or her hands off the controls, but neither will it diverge and fly itself into a steeper turn, roll, or pitch attitude hands-off.
Which manufacturer produced this fan blade? I acquired a fan blade a few years back, but have not had any luck finding out who manufactured it or what engine/aircraft it may have come from.The only data I can find on the blade is as follows: 4922T12P0199207 6018730P02KGA 65444GR.IN.15.620 65444 is hand engraved again...	The serial number are sequential. Besides the TF34 this almost exact fan blade also goes on the CF34 (Canadair Regional Jet).
Why does a Phugoid occur? How can it be eliminated? My model aircraft seems to do phugoid oscillations and I'm having trouble landing. It is around 2 kilos, very high mounted wing, so bad landing takes out the underbelly everytime. I'm wondering what's causing the phugoid, CG placement? The extremely high wing causing...	Move the tail further back by lengthening the fuselage: This will increase stability and, especially, damping, so the pitch motion after stall becomes less violent. What certainly will help is to move the center of gravity forward because this will increase static stability and require more trailing-edge-up elevator de...
I have really intense ear pain during descent in commercial flights. Would it be better or worse if I was flying a small non-pressurized plane? Usually — but not always — after descending in a commercial jet airliner, my ears really hurt for several days, accompanied by minor hearing loss. Nonetheless, I am still in l...	As other have said, the cabin altitude in typical non-pressurised GA airplanes will often be more favourable than in airliners, by the virtue of flying lower.
Does the FAA issue multiple physical certificates for different aircraft categories and privileges? If one holds a private pilot certificate in both airplanes and gliders, does the FAA issue two plastic cards that one would have to carry? What if one has commercial privileges in airplanes, but private in gliders? What...	The FAA only issues one "airman certificate" at a time.
How could the Helios 522 passengers have survived so long without oxygen? I've noticed some strange inconsistencies regarding the documentation of Helios Airways Flight 522 . So first: Autopsies on the crash victims showed that all were alive at the time of impact But then: The emergency oxygen supply in the pa...	Human beings can last remarkably long with very little oxygen, but not remain conscious.
Why don't we treat all takeoffs as short field in GA? Depending on the airframe, there are a number of techniques to reduce the Take Off Distance required. For example, deploying flaps. What advantage is there to NOT using short field take offs, even when runway length is sufficient? Surely it's always advantageous to...	All-in-all the short-field takeoff is just a relatively more dangerous way to take off if you have sufficient runway for a normal takeoff.
What exactly is the meaning of "detent" in aviation? I come across it in many different situations e.g. "settings changed to flight detent" or "landing altitude changes at first detent". There are other scenarios which I came across in the past, but I don't remember them. Could someone explain me all the different sc...	A detent is usually a discontinuity in force at a certain position: the control likes to move into that position, and moving it away takes more than average force.
Has there ever been an aircraft with three sets of flight controls? On every aircraft I know, there is either one set of flight controls if it is single-pilot operated, or two sets of flight controls allowing either the pilot or copilot full control. Has there ever been an aircraft that has three or more sets of fligh...	There have been a number of one-off aircraft which attached one plane's cockpit to another aircraft for testing or training purposes.
Rolling take off compared to take off from a standstill When ever I fly I choose flights with the most take off and landings. After going down the taxiway and turning onto the runway sometimes the flight crew ramp up the engines up while holding the airplane from moving with the brakes, then let off the brakes and the ...	Short field takeoffs involve lining the aircraft up on centerline as close to the threshold edge as possible, applying brake pressure while running the engines to full power, thence releasing the brakes and commence the takeoff roll.
What design features or systems help to prevent a hard nose landing? Pilots perform perfect manual landings almost all the time with the nose wheel touching down softly and elegantly. When landing an aircraft of any size really more so for the jumbos and super jumbos, this seems like an incredible feat given their weig...	Having the airplane in proper (elevator) trim as the power is reduced prior to touchdown, flying the nose wheel onto the runway by relaxing the back pressure on the yoke while the elevator is still effective and practice.
Why does the PA28 only have one door? I did the majority of my PPL training in a PA28 Warrior and I've recently started transitioning over to a C172 and one thing that amazes me is how convenient it is to have a door either side of the aircraft. My question is: Why does the PA28 only have one door on the passenger si...	It reduces weight and increases the structural strength of the fuselage, particularly with the typical design of a low wing aircraft. Besides Piper, most Mooney, Beechcraft, and Bellanca aircraft only have one door.
How is fuel weight calculated? I was having a conversation concerning airplanes and the calculated fuel. We were having a conversation about the Airbus A380. Based on this site: http://www.modernairliners.com/airbus-a380/airbus-a380-specs/ It shows a capacity of 320,000 Litres. After some conversion (I am in the US) ...	Fuel comes out of the bowser and is metered in Litres (at least where I come from!).
Why didn't Air India always fly DEL-SFO over the Pacific? I read a 2016 article that said Air India broke a record for the longest flight (distance) by flying from New Delhi to San Francisco over the Pacific rather than a polar/Atlantic route. The total flight time was shorter because of the jet stream. Why didn't t...	Taking the Pacific route instead of the polar route adds quite a significant amount of distance to the DEL-SFO flight. In short, when an airline selects a new challenging route, it must prove it is prepared for it, and to set up new training procedures.
Why not tow aircraft instead of single-engine taxi? To save costs, budget airlines could potentially eliminate the single-engine taxi that is standard. Companies are looking into things like electric motors on the wheels of airliners for taxi, which could be powered by the APU, using much less fuel than even a single-...	So the why not is basically: more traffic that doubles when the tow truck detaches, expenses (trucks, drivers, maintenance), reduced runway capacity, bigger chance for ground accidents, and a very complicated coordination task.
Why does the radome on the AWACS rotate? I'm not sure I understand why the radome on the AWACS aircraft is so large, and could somebody explain the design and why it has to rotate? <Q> Basically, the radar antenna of the AWACS system is just like this ( source ): <S> Rotating waveguide antenna (picture source ) <...	Since the radar beam is directional, like most radar beams, it has to be rotated to get 360d coverage.
What biplane is this model modelled after? What biplane is this model modelled after? <Q> Look at the cutout of the wing above the pilot's seat. <S> It's rectangular as on the Snipe , not a semicircle as on the Camel . <S> The engine looks like a Camel's however. <S> So, this model is possibly a hybrid of two famou...	The plane is probably modelled after both a Sopwith Snipe and a Sopwith Camel.
Is a weather briefing required? Are pilots legally required to obtain a weather briefing prior to some or all flights? <Q> Yes, at least for flights that are not in the "vicinity" of the airport. <S> FAA CFR 91.103 <S> Each pilot in command shall, before beginning a flight, become familiar with all available infor...	For a flight under IFR or a flight not in the vicinity of an airport, weather reports and forecasts , fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays of which the pilot in command has been advised by ATC; You are not required to call Flight Services for ...
Can I fly a UAS that weighs more than 55lbs if I'm on private property? Can I fly a UAS that weighs more than 55 pounds within my own private property if I stay below say, 200 feet? I do not have 333 exemption <Q> TL;DR <S> As far as I can tell, the rules don't specify zones or altitudes where the regulations aren't ...	According to the FAA Part 333 rules , all UA aircraft (> 55 lbs) must register with the FAA with an N-number before flight.
Do small aircraft have sockets for passenger headsets? I am currently training for my PPL. in the Cessna 182s we use I've only ever noticed two sets of ports for the headsets. If there were additional passengers in the back seats, how would they communicate? <Q> The rear seats of a Cessna 172 has headset jacks, I imagi...	Diamond aircraft have the plugs for all headset jacks on the aft section of the center console. It depends on the airplane and what year was manufactured in.
What is a "flare-out" and why does auto-thrust reduce thrust during flare-out? The functions of auto-thrust include thrust reduction during a flare-out . What is flare out and why during flare out will the auto-thrust reduce thrust? <Q> The proper term is "flare" not "flare-out". <S> Whether the pilot, or Auto Thrus...	"Flare" is a term used to describe the act of raising the nose of an aircraft in order to increase lift and stop descending in order to land on a runway smoothly.
What is it called when you roll without yawing or pitching? My instructor made me do an exercise that consists of banking the sailplane left and right around 30 degrees without moving from the axis. I need to aim for a specific point, and start with the exercise. This is a coordination exercise but does it have a name?...	Here at the University we call it a "Perfect Roll", it is commonly used to assess the turning characteristics of an aircraft. In addition to being (mistakenly) called a Dutch roll, I hear that maneuver called "rolling on a point" or "rolling on a heading.
What is the flight trajectory of a commercial airplane in regards to altitude v/s distance? So, my friend and I got into an argument regarding the flight trajectory of a plane. He said that for half the journey the plane is ascending and for the rest, it is descending and hence making a parabolic curve. I argued that i...	Both of you are somewhat right - in the way you mention.
Can the FAA stop the municipality owned airport from closing down? I live in Wheeling IL . Our town owns the municipal airport there. Most of the residences here want to close down the airport. Can the FAA stop us from closing the airport? <Q> Frequently, municipal airports are created and/or operated with funds gra...	Closures of airports are only impeded by the FAA (or other agencies) when there are contractual obligations.
Why is the first turbine in a turboprop (or turboshaft) connected to the compressor? Typically the first turbine after the combustion chamber drives the compressor as shown in this picture. ( wikimedia.org ) This first turbine spins the fastest and harvests the most energy from the gas flow. This seems inefficient wh...	The compressor obviously requires a power source, in order to do the work of compressing the air before it is mixed with the fuel.
If both propellers and wings are airfoils, then why do propellers deflect air perpendicularly to the rotor, but wings not? Here is my dilemma. I have seen a lot of videos of airfoils in wind tunnels, and I've noticed how the airflow always moves away from the trailing edge parallel to the wing, or at a very small angl...	For a given air-relative speed and airfoil shape, both a wing and a propeller will deflect the airflow the same amount: A propeller does not deflect the air perpendcular to the rotor, it provides thrust in that direction.
Why B-52 engines produce lots of smoke only during take-off? During the flight it seems there is no smoke, it's only during takeoff. Here is an example This question explains that smoke is caused by unburnt fuel but why is there so much more during takeoff? <Q> There are a few reasons. <S> The first is that the ...	As the aircraft moves faster, it's easier for it to get more air into the engine, which helps it run more efficiently. The B-52 still uses older generation engines.
Are private jets allowed to land at London Heathrow? Heathrow is among the worlds busiest airports, with traffic mostly (entirely?) from airliners. Are private/business jets (e.g. Gulfstream G650 or Cessna Citation X) allowed to land at Heathrow? If so, what are the landing fees and what criteria do they use in chargi...	Yes, Private jets can land at Heathrow.
How long does it take to assemble an Airbus A380? How long does it take to assemble an Airbus A380? <Q> Airplanes are not built like cars where after completion, they are showcased at dealership to attract prospective buyers. <S> For larger commercial airplanes, airlines place an order first and then wait for the airpl...	When the assembly line is working at full speed, Airbus can deliver about 30 A380 planes a year, doing so in 2012 and 2014.
Do Federal Regulations really require compliance with all crewmember instructions? On commercial flights, we're frequently told that all passengers are "required to comply with lighted signs and placards, and all crew member instructions". But when it comes to the CFRs, the closest I can find is 14 CFR 121.571 ...	For U.S. Air Carriers FAR Part 121 requires passenger compliance with specific instructions as specified in subparagraph (k) shown in the excerpt below: ( here is a link to the entire regulation shown below )
Why do landing gear tires smoke upon touchdown? I have been observing several aircraft landings and have noticed that when the aircraft's landing gear touches down, it precipitates the rising of a cloud of smoke. Why is this? (Source: airliners.net ) <Q> Because the tires are momentarily skidding on the pavement as t...	Anytime a tire's bottom is moving at a significantly different speed than the roadway, it'll make smoke.
Are steam gauges more reliable than glass panels? I have always had a deep appreciation for technology and the future and I encourage that technology should move us forward whether that be in aviation terms or otherwise but one question has been on my mind for a very long time and that is why we have computerized gauge...	Glass panels are more reliable and accurate in every way over steam gauges.
Why are parking brakes not used for parking jetliners? From the question ' Do I Set the Parking Brake On the Ramp? ' it is concluded that you do not set the parking brake when parking the aircraft. The question concerns small aircraft which can be parked for a longer period of time. However, commercial jets (jetliners...	Parking brakes are used by commercial aircraft at the gate if the ground crew can not set the chocks.
Why wasn't there a belly gunner on the B-25 Mitchell? The B-25 Mitchell doesn't have a belly gunner, which would seem quite dangerous. Why didn't it have one? <Q> The production B-25B, B-25C, B-25D, and some B-25G models did have retractable remote control belly turrets. <S> They were often removed in the field because...	In the Pacific Southwest, the turrets were immediately removed and replaced with fuel tanks to increase range and also because monsoon rains turned airfields into mud which covered the gunsight on takeoff rendering the turret useless.
If a circling airplane (AC-130) fires a bullet how does the plane's trajectory alter the shell's flight path? Background: An AC-130 is a military aircraft that has a cannon that fires out the side of its fuselage. If an AC-130 (or similar aircraft) is traveling in straight, level flight at a constant rate of speed ...	When a projectile is fired from a gun in a fixed wing aircraft or helicopter in a direction perpendicular to the direction of flight, the airflow across the muzzle has an effect on the trajectory which is known as "bullet jump", the deflection can be upwards or downwards depending on the direction of the rifling of the...
Can an airplane engine fire be extinguished without shutting down the engine? Airplane engines catch fire from time to time (and are falsely reported as being on fire even more often). In a modern airliner, the "fire handle" shuts down the engine, closes the fuel pipe, and discharges the fire extinguisher. Occasional...	Even aircraft that do not have fire suppression systems (such as the B-52), require the fire handle to be pulled if you have a fire indication, which shuts off the engine. So, if you are asking about modern jets, the answer would be no
Is this XKCD comic list about autogyro features accurate? I recently came across this XKCD comic which gives you a number of facts about autogyros: Image is copyright XKCD, licensed under CC 2.5 BY-NC I'm not sure if this is satirical or really drawing attention to some very odd real-world facts, or a mix of the ...	Re the "Can often be flown without a license" this is true in the US for certain types of gyro - small, one-person craft which are classed as part 103 aircraft.
Does the speed of the air molecules matter in aircraft performance? Does the fact that air molecules move slower in cold weather and faster in hot weather also affect the aircraft's performance or no? So if its cold there is a higher chance or air molecules hitting the wing and engines because the air molecules are com...	Aircraft performance is dependent on density altitude, which considers not only the pressure altitude, (displayed on your altimeter), but air temperature as well. The fact that the air molecules are moving faster when it is hotter is irrelevant, because this speed is the average speed of the molecules.
What does RPM mean in a propellor aircraft, compared to a jet aircraft? What is the practical significance of speed RPM in a propeller aircraft for a pilot? I am not able to correlate it with RPM in jet engines? <Q> RPM in a propeller aircraft is typically under 2400, as the prop spins at the engine RPM speed. <S> Abov...	If the propeller has a fixed (nonadjustable) pitch, then the RPM of the propeller is a simple indication of the power output of the engine, and the pilot manages engine power by adjusting tachometer RPM with the throttle.
How to select a SID during the planning stage? During the planning stage of an IFR flight how to choose the correct SID for your route in an airport with multiple runways and multiple SIDs? and how to predict the runway you will be going to use? <Q> "File what you want, fly what you get." <S> There's no way to know f...	EFB apps like ForeFlight do have the capability to show previously cleared routes so you can get a sense of how ATC likes to handle airplanes for those routes.
Why would a stretch variant need a larger horizontal stabilizer? Update and accept reason The reason for asking why would as opposed to why does is I was not aware of any previous [jetliner] stretch requiring a larger horizontal stabilizer. For example, all the DC-8's from shortest to longest (almost the same stre...	When the fuselage is stretched, the arm of the horizontal stabiliser is increased, and hence it's effectiveness increases linearly with the fuselage length.
What is the difference between buffeting and fluttering? As I understand, both are dynamic effects of aeroelasticity - however, what is the exact difference between buffeting and flutter? <Q> The vernacular meaning is... 1) <S> Flutter is un-commanded self perpetuating (positive feedback) destructive & adverse cycl...	Both buffet and flutter is a vibration of a surface of the aircraft, such as a wing or tail, due to the air flowing over it (especially if the air is turbulent). Buffeting is usually considered undesirable but benign and not a destructive force.
Do aircraft automatically send a message to the ground if there is a catastrophic failure? For example, if there is a engine failure, it will be displayed on EICAS as a CAS message. As per my knowledge, the pilot will initiate the contact with any ground station nearby for guidance to land safely. Iis there any equipme...	In many cases, the ACARS is configured to transmit flight data automatically (engine performance, airspeed, altitude, etc) that would include error messages/warnings from the various systems onboard.
How are engines numbered? On a commercial aircraft, the number of engine is usually 2, 4 or 6. When the technician or LAE was given task to inspect an aircraft engine no 2 on a 4 engine aircraft. Which engine would they go to? 2 different lecturers of mine had 2 different answer for this and both have experience in wo...	The Wikipedia article is clear: engines are numbered sequentially, left to right, as seen by the pilot facing forward.
Is there any alternative to isolating the vibration of an ultralight engine other than using engine mounts? Is there any alternative to isolating the vibration of an ultralight engine other than using engine mounts? <Q> Similar in principle to Active Noise Reduction headsets that generate an inverse pressure wave to ca...	You can prevent engine vibrations from being transmitted to the airframe by motion cancellation techniques.
What is the maximum altitude ATC would deal with? What's the maximum altitude ATC would deal with? Any example of jets service ceiling certified for above 45.000? Commercial & Business jets? <Q> There are many examples of aircraft with high service ceilings. <S> That being said, military jets can fly higher and will b...	ATC will deal with anything that flies over their airspace. While most commercial aircraft have service ceilings of FL410 and rarely fly even that high, many business jets have a service ceiling of FL510, such as the Dassault Falcon 7X , Gulfstream G650 , and Bombardier Global Express .
What is it called when an airplane has to circle because it can't land? Sometimes, a plane is required to circle around an airport repeatedly because for whatever reason, it is not able or permitted to land just yet. This state in which a plane is stuck in the air in this way has a name, what is it? <Q> <A> There is ...	Depending on the way the aircraft is circling the airspace, specific names can be used. It's called a holding pattern.
What radio equipment do pilots use to communicate with ATC? I know of the transponders used for communication by Air Traffic Control, but apart from that, what radio equipment do pilots use to talk to ATC? What modulation method is used? <Q> https://en.wikipedia.org/wiki/Airband emphasis added As of 2012, most count...	The major communication tools are obviously Vhf radios for voice, another one is HF, particularly in remote place or oceanic.
Does it help to climb in case of a partial engine failure? When the engines of a airplane show irregularities that do not reduce performance but indicate a possible failure of the engines, is it useful to climb to a higher level, to increase the glide length that is available in case the engines stop completely? The ...	In fact, lowering your elevation and speed will greatly reduce the stress/strain you are putting on the engine and will likely give you a better chance of making it safely to the closest airfield.
How can a two-engine B787 create three contrails? Today I noticed overflying aircraft (over Sydney at FL400) which appeared to have three contrails. When I checked Flightradar24 app, I saw that this overflying aircraft is B787.What would be the reason for three contrails with only two engines? Could the third be caused...	Contrails are created due to variances in the pressure of the air, coupled with the amount of moisture in that air.
Do Airbus aircraft have an "off" position for their landing gear? I know some Boeing aircraft feature an up, down, and "off" position for their landing gear lever. I know that some Boeing wide-body jets do not have a 3rd lever position, but still have an "automatic" "off" setting that takes effect after a time-delay ...	Yes, Airbus aircraft used to have an OFF position (called NEUTRAL ) for the landing gear lever on the A300 and A310 .
Do ATC displays show the target altitude that the pilot has set in the autopilot? When cleared to climb/descend to a level, the pilot enters that level in an altitude preset window, allowing the autopilot to climb/descend and level off at that level. Is this level, preset by the pilot, visible on an ATC radar screen? <...	Yes, our radar is indeed capable to display data of the Mode S Enhanced Surveillance Transponder like Selected altitude, IAS, Mach Number, Heading and more.
Why do localizer/glideslopes use 90/150Hz specifically? Why is it that localizer and glideslope system are using 90 Hz and 150 Hz frequencies only, instead of some other LF such as 75 Hz? Part two of my question:How does the modulation depth differ for aircraft using localizer and GS receiver? <Q> Read through this Q...	The frequencies are chosen to allow the system to produce a localizer and glideslope 'beam' that provides proportional guidance that can adequately guide an aircraft on the approach.
What is the difference between axial compressor blades and centrifugal compressor blades? Is there a particular difference? The way they're overhauled is the same ? (I mean do we use the same overhauling methods ?) <Q> The blades are shaped completely differently. <S> Typically a centrifugal compressor is one solid pi...	Flow through a centrifugal compressor is turned perpendicular to the axis of rotation, while air in an axial compressor flows parallel to the axis of rotation.
During the holding procedure is it required that the pax must have the seat belt on? Imagine to have to hold at a busy airport before landing for a quite long time (let's say 20 plus minutes), does it requires that the pax must have the seat belt on during the whole holding procedure? Is it required by the Authority or...	There are no regulations which require passengers to be seated when the plane is flying a holding pattern, but there are a few practical advantages to keep the seat belt sign on during this phase:
Are there any regulations preventing one from converting an originally cargo aircraft to ferry passengers? Are there any regulations preventing one from converting the cargo version of the Airbus A380 for passenger use? <Q> Converting a freighter to an airliner would require lots of work: <S> you have to install an...	To answer the specifics on an A380 conversion, one would have to study the type certification and the delivery configuration of a given aircraft, and then analyze the requirements to move to dedicated passenger service.
Which modern day prop (piston) engines allow for inverted flight? A buddy of mine is looking to buy an airplane with an old radial engine because he says radial engines can fly inverted in aerobatic flying. What modern day engines (engines that you can buy today), are capable of flying in inverted flight? <Q> The Ame...	Any “modern day” piston engine can allow for inverted flight if it has the right equipment on it.
Why not increase the number of Flight Data Recorders and add jettisoning capability? With some Flight Data Recorders gone unrecoverable during crashes , what's the argument for not changing their locations, like wings or engines? Given their utility after accidents, why not increase the redundancy even more by placi...	In theory, it could be possible to jettison an engine on a wing mounted engine aircraft, because they have fallen off on their own and the airplane was still flyable because there was little CG shift.
Clearance limit of VFR practice IFR approach? When a VFR aircraft has been approved by atc to perform a practice approach, is the aircraft also cleared for a published missed approach procedure? <Q> I'm assuming you're asking about the US, in which case the answer is no. <S> The AIM 4-3-1(e) <S> says: VFR aircraf...	When you are IFR you are not technically cleared for the missed approach procedure either in accordance with the standard definition of the term.
Are frisbees and boomerangs technically gliders? Frisbees and Boomerangs are heavier-than-air, unpowered, and fly through the air. So are they technically gliders? They also rotate, so I wonder if these are actually some kind of rotorcraft-type gliders. I looked up all types of rotorcraft on wikipedia, which listed ...	"The Federal Aviation Administration (FAA) defines a glider as a heavier-than-air aircraft that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose free flight does not depend principally on an engine. "
Could a plane land on specialized vehicles if its landing gear failed? This (fake) video has stirred up a lot of questions online about whether such a scenario would be possible in reality - and the answer to those questions appears to be a resounding "No, that's very implausible." But most of those answers seem to f...	Sure stunt pilots can do similar things in small planes but those planes fly much slower and are much more manoeuvrable than an airliner.
What is the difference in VTOL technology between British Aerospace Harrier II and F-35B? F-35B safer and looks more stable in terms of VTOL capability. What is the basic difference between Harrier II and F-35B's VTOL technology? <Q> the F35 has a ton of electronics that the Harrier could only dream about, but I wi...	The Harrier system is much less complex mechanically and avoids the need for the lift fan which is only used for take off and landing and is dead weight the rest of the time, and which also takes up a lot of space in the F35B's forward fuselage.
Is this a Hurricane or Spitfire? Can anyone identify the fighter here in this picture taken from a Dornier-do17? From: https://stukablr.tumblr.com/post/145040185970/a-pic-took-it-from-a-donier-do17-a-hurricane <Q> Relative thickness of the airfoil, thickness repartition over span, and low dihedral angle of the enti...	The radiator is on the fuselage, which means it is a Hurricane.
Does a Tower controller need to see an aircraft on final to give landing clearance? If there is an IFR aircraft on approach that has already received an approach clearance, and he reports being at the final approach fix but the controller does not have him in sight yet, can the controller give the aircraft clearance to...	No, a tower controller does not need to have an aircraft in sight in order to issue a landing clearance.
Which aircraft have fought against its own type in active combat? The criteria for this question are The aircraft has to be the same type (but not necessarily the same mark) The two opposing sides are actively hostile; but not restricted to nation states (so civil war a possibility) The aircraft treat each other a...	There was an account of Soviet MiG-17s engaging in a fight with Hungarian MiG-15bis in 1956 (I could only find an archive quote now).
Is it possible to build a flight-capable aircraft powered by compressed gas? I pray this isn't a physics SE question. A star engine can be considered "gas operated". So what if we power a star engine with unleashed, formerly compressed gas instead of... actual gas/aero-kerosene/etc...? So instead of fuel tank (oh the ...	There is no way you can offset the enormous amount of compressed air required by downsizing your engines.
What are the differences between the MiG-15 and MiG-17? Apart from the extra wing fence and angled leading edge of the MiG-17, what are the differences visually between the two aircraft? <Q> I'm surprised <S> no-one's mentioned the length - the MiG-15 has a much stubbier appearance than the MiG-17, because it was rathe...	The MiG-17, being developed much later was meant to be a far more advanced aircraft compared to the MiG-15.
How to find the flight paths of an airport? How can I find the flight paths near an airport (e.g., Heathrow or Pearson) including cruising altitude, descending speed (variations)? Specifically, I need a figure showing the height vs. speed of a plane as it's landing starting from the cruising altitude. <Q> You can find...	If you check out a variety of flights into the same airport, you can see what approach paths are used by aircraft arriving from different directions for the current wind conditions.
Why do simultaneous-ops parallel runways need to be so far apart? In the answers to this question about Denver's widely-scattered pinwheel of runways and this question about Schiphol's runway out in the middle of nowhere , it's mentioned that parallel runways are required, by both European and U.S. regulations t...	It is usually to guarantee sufficient aircraft separation when visual separation is not available (bad weather).
How bad is the efficiency of jet engines under low loads? VTOL operations need 4-5 times more thrust than a conventional take-off of an aircraft. If you don't want to install additional lift-engines into a hypothetical aircraft and use thrust vectoring to turn the thrust towards the ground, you naturally end up with ...	The main problem with installing bigger engines is that they are heavier.
Is this statistic about the fatal accident rate correct? This link says that: fatal accidents occurred once every 200,000 flights in the 50s and 60s. Now, fatal accidents only occur once every two million flights While many sources, including this one , agree that the average number of commercial flights per day ...	The statistic of 100,000 flights per day is a global one, and globally it is not true that there were no commercial airline fatalities in 2017. In 2016 there were 14 incidents, which is closer to the quoted average.
Is it incorrect to refer to a C-130 as a jet? In this article by CNN, the C-130 involved in the unfortunate crash in Savannah, GA is referred to as a "jet." Is this considered proper usage? I'm not looking for public opinion here but official categorization, if one exists. Perhaps there is an USAF or FAA document I'v...	The FAA Pilot's Glossary defines a Turboprop... There is probably no official definition of this term, but this is how it is commonly used.
How do I tell ATC that I don't have a transponder? If my plane doesn't have a transponder and ATC tells me to squawk some transponder code, how should I respond? Is it just as simple as "I don't have a transponder"? This is for the United States and for a plane with no electrical system, and obviously at a towered fie...	In the US if you are flying in Class G airspace or Class E below 10,000 feet you are not required to have a transponder.
Has there been an aircraft with multiple type of engines? Has there ever been an aircraft that can fly using at least two different type of engines? For example, a piston engine and a turbine engine, or a piston engine and a electric motor. To clarify the question: It is not necessary to operate both engines at the ...	Fireball was a hybrid powered fighter, looking much like a conventional WWII era piston powered fighter but had an additional jet engine in the tail of the aircraft to be used in high speed flight. Peacemaker had six Pratt and Whitney radial piston engine propellers and four GE turbojets.
Is it possible for a fighter jet to shoot itself down with an IR missile? In this answer , it's mentioned that However, IR missiles (AIM-9 Sidewinder, AA-11 Archer, MICA IR, ASRAAM) do not emit any EMR that indicates they're incoming; they use a passive FLIR sensor to identify and track the heat source they were tol...	Yes, but not in the way you're thinking As a general rule, a missile shouldn't get turned around like that -- if it did so as a sustained maneuver, it'd be vastly short on energy and thus easy to evade in addition to being well out in front of the launching aircraft, making a "circular running missile" self-shootdown s...
What are the limitations to adding wings with engines to a helicopter? I've probably seen this in science fiction and cartoons but never in real life. Rotor wing aircraft (helicopters) have numerous advantages over their fixed wing counterparts, and vice versa. For example, helicopters can take off and land vertically ...	Your concept may be capable of faster travelling and higher payloads than the V-22 (which rotors are too small for heavy lifting and too big for fast flying), but the real question is whether the added weight due to the complexity of this concept will offset the theoretical performance gain. Folding in flight has only ...
Why was the Concorde painted white and not black? It's well-known that the stated reason the Concorde was painted predominantly white was to mitigate heating problems . However, given that the source of the Concorde's thermal woes wasn't excessive exposure to solar radiation, but, rather, direct conduction and convec...	Short answer shorter, the aluminum on the Concorde didn't get hot enough for the aluminum to lose integrity, so white was the better option in terms of preventing the metal from reaching those critical temperatures.
Do modern aircraft require rudder input in order to perform a coordinated turn? With today's state-of-the-art electronic systems in modern aircraft, do aircraft equipped with autopilot systems, still require pilot rudder input to keep a turn coordinated? For the context, I'm assuming the pilot is hand-flying the aircr...	With a Y/D system the only time a pilot really needs to make a rudder input in flight is if an engine quits, because the yaw damper's authority is not sufficient to counter asymmetric thrust. The need for rudder to coordinate a turn is directly dependent on Angle of Attack (AOA).
Why do narrowbodies have longer life than widebodies? Is it fair to say that narrowbody aircraft have a longer life than widebody aircraft? This is the conclusion drawn from a report written by Dick Forsburg from Avolon (.pdf), where he says that the average life of a narrowbody is 26.6 years, while the average life ...	In many ways, narrowbodies may "wear out" faster as they typically fly shorter routes and accumulate more cycles in a shorter period of time. The cycle length is the biggest factor I think. Airplanes get retired when operating them is no longer profitable.
What is this plane doing flying back and forth near Sydney at night? As I write this, a mystery plane is going back and forth over south Sydney, Australia: The plane took of at Bankstown, flies straight from West to East and back, with a distance between paths of about 600m. It maintains a steady height of ca. 4100...	Flights that have that kind of pattern are usually doing some kind of aerial photography. Another possibility is that the plane could be collecting LIDAR data to get a 3D model of the city.
When to switch from ground to tower frequencies at controlled airports in the US? I have heard that you can switch to the tower frequency once you are at the runway hold line and are ready for takeoff without getting permission from ground control to switch frequencies. Is this always true or does the procedure vary f...	You might ask to change, say you only have one radio and you want the latest ATIS, in which case you request to change, and wait until they give you positive indication that is okay.
How do banner tow planes coordinate with air traffic control? I tried searching with terms I think were correct around the net, but no satisfying results. I have seem many times small planes circling around when there is some special event going on. They have advertising banners trailing behind them. For busy airspac...	Notify appropriate airport officials in advance when banner tow operations will be in close proximity to each non-towered airport.
Will the steep beta descent mode become illegal for new aircraft? The PC6 is a popular skydiver carrier due to its ability to use steep nose down beta descent to get back to the ground quickly, even beating free falling skydivers. ( YouTube ) FAA AC25.1155x (I only saw the draft) proposes that a "means to prevent in...	Unless it’s approved for your aircraft, don’t even think about it.
What is the correct ATC phraseology in the US for an immediate - no delay takeoff? Just wondering - what's the correct ATC phraseology for a takeoff where a plane does not stop first after lining up with the runway centerline before starting their takeoff roll? Redwood five-two-six-three, runway three-zero cleared fo...	EXPEDITE− Used by ATC when prompt compliance is required to avoid the development of an imminent situation. My experience has always had the clearance be "no delays".
What is the average angle of attack of GA airplanes during takeoff? What is the average angle of attack of GA airplanes during takeoff? <Q> Depends on how slow you are going at rotation, and how aggressively you rotate. <S> Stalling AOA of most GA wings is somewhere in the region of 14-16 degrees and on takeoff it shou...	About all that can be said about AOA during takeoff is that it starts out very low, (in tricycle aircraft anyway, in tail dragger it starts out high until the pilot pops the tail off the ground) then, at rotation, increases to something higher than climb AOA, but lower than stall AOA, then decreases as the aircraft acc...
Why would the Speedbrake be required for such a long time on approach? As far as I was aware, the Speedbrake is designed to slow the aircraft down. On landing, I do understand why they are required. Once the aircraft has hit the tarmac, they are deployed to 1) slow the aircraft and 2) prevent the aircraft from bouncing...	Speed brakes are often used on aircraft that are very clean (i.e., have very low drag), and, as a result cannot descend at a steep enough glide angle even with power at idle to satisfy minimum descent gradients for some specific phase of flight.
Are there any data on the safety rate of gliders vs single-engine GA aircraft? Can anyone point me to statistics on the safety record of gliders vs. single engine general aviation aircraft? <Q> I had three days to burn so I took a look.) <S> Comparative data was very difficult to find beyond accident counts, so dete...	It is hard to compare because of hours flown... There are a lot of non fatal accidents. Fatal glider accidents (no particular order) seems to be in-flight break up, stalls and collision with ground (typically in mountainous terrain).
Why is it 'aileron right and elevator up' with a front-right wind in a tailwheel airplane? Question: How should the flight controls be held while taxiing a tailwheel airplane into a right quartering headwind? Answer: When taxiing a tailwheel airplane into a right quartering headwind, use up aileron on the right hand ...	On a tailwheel aircraft, keeping load firmly on the rear wheel helps provide directional stability and reduces any tendency to pitch forward on braking or when negotiating uneven ground, which in severe cases could risk a prop strike.
Is the increased humidity on modern jets artificial? Is the increased humidity on jets such as the 787 and A350 artificial? Or is it a direct result of a greater cabin pressure? <Q> A Reuters article confirms the humidity just comes from the passengers, on the 787 at anyway: <S> (...) the air is dry and moisture c...	Coming with some ECS/Pressurization background in engineering tech support, the only factor I can think of where higher pressure differential would influence humidity, which is all coming from passengers, would be related to leak rate of the pressure hull (they all leak, mostly through door seals etc).
Why ground a plane while fueling? Why does a plane need to be grounded while fueling, but we never ground our cars? Does the potential for a spark magically exist for an airborne vehicle but not for an earth bound one? <Q> On cars I think it's because static charges don't build up as much <S> but theoretically it's sti...	According to reddit , the amount of fuel transferred when refuelling a car is generally too small to generate a dangerous amount of static charge, and you actually do ground your car when you fill it, the action of touching the nozzle to the filler hole grounds it.
Why is the 737 MAX 7 selling so poorly? The 737 MAX 7 is the smallest of the four major variants in Boeing's 737 MAX product line; it is intended as the successor to the highly-successful 737-700, and features a higher fuel efficiency, considerably greater capacity, and increased range compared to the 737-700. Yet it ...	The 737-7 is a smallest version of the family so some of the operating costs are fixed by the larger models. There is new competition from the Bombardier CS300 (now Airbus A220-300), which carries 130 seats in a 2-class configuration, and the Embraer E195-E2, which carries 120 in a 2-class configuration.
Why wing ribs have diagonal struts Why do ribs have diagonal struts,why not vertical as seen in airfoils of Citabria airplane? <Q> The diagonal struts are best to transfer shear. <S> Imagine an upward pointing load at the nose. <S> In order to get that load transferred to the fuselage, it first needs to be transferred ...	So, in short: the diagonal struts transfer shear loads to increase torsion strength and stiffness of the wing.
Where does the Departure End of Runway (DER) exactly begin? I am having trouble understanding the concept of Departure End of Runway. Most sources state that DER is at the end of the portion of the runway that can be used for takeoff (which, as far as I can tell, excludes the threshold at the end of the runway). But f...	According to the FAA's Terminal Instrument Procedures (TERPS) , the definition is: Departure end of runway (DER).
What was the value proposition of the 767-400ER over the 777? Aside from visible differences, what are some differences in the usage and design of the 767-400ER as compared to the 777-200/200ER (or 300/ER if you feel makes more sense)? What was the value proposition of the 767-400ER when compared to the 777, as both c...	If you can get the customers who want to replace their DC-10s and L-1011s with the more comparable A330-200 (which entered service in 1998) in talks about the 767-400ER, you have a shot at selling the bigger 777 as well.
Why aren't there aircraft with forward-mounted vertical stabilizers? Many aircraft have the horizontal stabilizers mounted in front of the main wings (this is called a canard configuration); however, to the best of my knowledge, there don't seem to be any aircraft with vertical stabilizers in front of the wings. W...	Because having the vertical fin fwd of the CG causes static and dynamic instability and requires an augmented flight control system in order to prevent the aircraft from spinning.
Are piezoelectric energy harvesters too expensive to be used commercially as a power source in drones or small aircraft? Piezoelectric energy harvesters can draw energy from the mechanical loads and the vibrations in the fuselage/wings/blades of aircraft. What are the disadvantages of such a system being used as an a...	You would need a very large number of them to produce useful amounts of power from airframe vibrations. Piezo harvesting is being developed to power completely unattended tiny sensors that won't have access to any other power source for years.
How does the nozzle diameter affect the thrust of a ducted propeller? I currently do some experiments with ducted propellers in which I try to figure out which effect a nozzle has on the thrust produced. My theory goes like this: If I reduce the exit diameter of the duct the pressure is going to decrease and the air ve...	Narrowing the "exhaust end" will increase pressure in the duct, which is what you want a compressor to do.

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