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Won't sonic booms prevent Space X's BFR intercity transport plan from being acceptable? Considering that Space X have just announced that their BFR can take anyone anywhere in the world in under 1 hour, that would be enormous speed, does this rocket not produce sonic boom? If not is it because of its shape and that it...	Since the rocket will be traveling through space, there will be no noise on the ground during cruise.
Were WW2 American fighters designed to operate from dirt airstrips? Fighter or fighter-bomber planes built in America during WW2, such as the P-36 , P-39 , P-47 , P-51 . Were these designed to takeoff and land on dirt airstrips? My impression, and correct me if I'm wrong, is the following: Most airbases inside US...	Later in the war, the Allies tended to have prepared runways because they had much better supply and field engineering support than the Axis powers.
What prevents companies like Cessna and Piper from connecting multiple alternators to a single engine? Firstly, I'm not even sure if there's only one alternator connected to the engine in a C172-like aircraft. But if that is true, then why don't manufacturers connect multiple alternators to a single? What are the draw-...	Having more than one alternator would introduce more complexity not only mechanically but also in the electric system (even if they work correctly).
What are the main differences between Flares and Chaff? Over the years I've heard the two used almost interchangeably but after watching some videos it would seem that they each have specific and particular functions. <Q> Both chaff and flares are defensive countermeasures deployed by military aircraft. <S> The purpose...	Flare is used to spoof heat seeking (passive) missiles. In both cases they are employed to try to divert a missile from his target.
Is it correct to say "the up-elevator position decreases the camber of the elevator"? Aft movement of the control column deflects the trailing edge of the elevator surface up. This is usually referred to as the up-elevator position. The up-elevator position decreases the camber of the elevator (my emphasis) and ...	You're absolutely correct, camber equals curvature.
How dissimilar are redundant flight control computers? Facts On Airbus aircraft there are computers to secure the flight envelope, or to move the control surfaces. FADECs totally control the engines. Computers take decisions in place of the pilots, or even against their commands. Boeing aircraft have similar computers...	On Airbus airliners, two different computers are used (one with Intel chips, the other with Motorola chips in case of the A320) and software is written twice, one for control, the other for monitoring, by two teams which are not allowed to interact.
Why would one wing stall before the other? Reading about the Douglas C-133 , I see this: The second issue discovered was stall characteristics gave very little warning to the crew. The left wing was found to stall before the right wing. The fix was simple, a small strip of metal was attached to the right wing cau...	Any difference of the wing shape, airfoil size, or airfoil shape between one wing and the other can also result in one wing stalling more easily than the other.
Why stall on 2D faster than 3D? why cl on 2D is better than 3D. and why cl 2D stall faster than 3D? what happens when CP continues to move forward on the wing. and what happens when CP continues to move forward on the elevator. <Q> This explains the stall at higher AoA because the additional airflow over the wing surf...	The 3D-wing allows for air to flow over the wingtip into the low pressure zone over the wing, thus reducing the overall pressure differential and reducing overall lift.
Is a destination airport necessary for cross-country VFR departure clearance? New flyer here. When you’re requesting departure clearance for a cross-country VFR, do you have to specify the destination airport to the controller, or can you just specify a direction (eg. “VFR to the south”)? <Q> Just say direction of flig...	If you request flight following when you call Clearance, they will generally want to know which direction you're heading.
Why are airplanes sometimes led by a vehicle? Airplanes are sometimes led by a vehicle on taxiways until they reach the runway or stand, why is this? <Q> "Follow-me cars", as they are known, make it easier for pilots to get to the correct spot by the correct route. <S> This could be the runway before take-off, or the...	They might be used as a rule at a particular airport, or on request (if perhaps the pilot is unfamiliar with the taxiways, or there's an urgent need to get to a gate very quickly), or because of local conditions (signage or lighting problems, re-routing because of ground maintenance work).
Can I take the FAA CFI knowledge exam(s) based on my EASA ATPL knowledge? One of the requirements to be a flight instructor in the USA is FAA theoretical exams. Can I sit those exams with EASA ATPL theory basis? Also, do I have the right to sit those exams without completing an official FAA theory exam preparation p...	the answer is no, you definitely would have to take the exam, although I don't think that's your question.
Why is Python used on aircraft although it may not be certifiable? I recently had a discussion with people who were active in the aviation industry and told me that one of the main languages/tools they use is Python. On the other hand I have always known that people avoid C++ or eg Linux due to certification reasons...	Python is an excellent language for all that validation work, even though it stays on the ground.
Is a license required to transmit in the designated aviation band? Is an FCC license required for people to operate a radio in the aviation band? <Q> These are covered in Part 87 of the FCC regulations. <S> Travel outside the US requires a station license, and I believe HF transmissions require a license. <S> Simil...	The FCC does not presently require a license for Aviation Radio installations in aircraft, where those are VHF and UHF (as I recall).
Do helicopters fly holding patterns under IFR? If a helicopter is flying an IFR flight plan, and the airspace around the destination is busy, will controllers tell them to fly holding patterns just like planes do? Or will they hover at the holding fix? Or something else entirely? <Q> just like airplanes. <S> Hovering...	In short, yes, helicopters fly procedure turns, hold, etc.
When using the phonetic alphabet, for airways, should we say Uniform or Upper? Listening some RTs, I heard ATCos reporting airways, for example: UL65, UPPER LIMA 65. But the phonetic alphabet says UNIFORM. Why do they say like this, please? Is there any manual in which we can study these differences? <Q> ICAO ICAO Ann...	The phraseology for the letter U is indeed " Uniform " as you can see on the specification of the NATO phonetic alphabet .
Who activates the fasten seat belt warning on commercial flights? Who activates (and de-activates) the "fasten seat belt" warning on commercial flights? I would guess it is either the pilot in command (normally the captain) or the first officer (co-pilot). If the answer is airline specific, then answer for American Ai...	Depending to the Standard Operating Procedures of each airline, the Pilot Flying or the Pilot in Command will switch on the Fasten Seatbelts Sign, on takeoff, landing and when required mid-flight at their own discretion.
Was the "Air Berlin" lap of honor over Düsseldorf problematic? A few days ago, flight AB 7001 (Air Berlin, New York - Düsseldorf) went for a "lap of honor" around the airport. One video can be found here . No emergency or technical issue, it just was that airlines last ever flight on that route (they're bankrupt), and...	It looks to me to be a simple "go-around" - a maneuver the pilots would be expected to execute if the runway were to become unavailable shortly before landing. Doing something dramatic and unsafe makes it very difficult to continue in their career.
Why are most runways laid out in a generally East-West direction? Runways are named by a number between 01 and 36, which is generally the magnetic azimuth of the runway's heading in decadegrees. From what I have read, most airport runways are aligned along an East-West corridor. Why is the North-South direction rarely ...	As most winds blow from West to east in the continental United States, most runways will be oriented approximately in that direction.
Has anyone been able to verify ADS-B works without radar? I know that one of the biggest advantages of ADS-B is "supposed" to be that it will directly communicate between equipped aircraft without ground support. Has anyone actually seen that in action? That is, seeing another aircraft on an ADS-B display where radar c...	Radar is not a component of ADS-B; so by definition it can operate in the absence of radar.
Can lift be created without air downwash? I was looking at the great site code7700.com , but I don't really understand their explanation of lift and drag: The so-called infinite wing displaces air for a while, but the air particles return to their original positions along the relative wind. The relative wind e...	Most if not all phenomenons producing lift can by explained by or can be linked to downwash.
What do pilots do on a windshear alert after V1? What is a pilot taught to do, when a windshear is detected and the planes speed is above V1 and before Vr? I can't think of what is safer. Rejecting, with the risk of overshooting the runway. Taking off, with the risk of the windshear stalling the plane and dropping ...	Unless the aircraft is suffering a catastrophic failure, the pilot should not abort takeoff after V1. If sustained positive rate of climb is possible and attained, retract the gear to remove parasite drag.
What is the difference between a go-around and a missed approach? What is the difference between a go-around and a missed approach? What are the steps involved in each of the procedures? <Q> Approach, missed approach, departure & holding Approach, missed approach, departure and holding are published instrument procedu...	A go around is terminology generally used during VFR flight . A missed approach procedure tells you how to get from climb out into a holding or to another point from where you can commence a new approach.
Where could I find a MATLAB implementation of TCAS algorithms? Where could I find a MATLAB implementation of TCAS algorithms and simulation? My research work deals with collision avoidance of a multi-UAV scenario in a small airspace. <Q> I doubt they will release it, but it's worth trying to start there . <S> Other...	MIT LL did indeed build a TCAS model in Simulink/Matlab which was used to validate the algorithms.
Why do control towers have tilted glass panels? Almost all control towers I've seen have tilted glass panels: Amsterdam-Schiphol tower (EHAM), source . What is the reason behind this choice? How is the tilt angle determined? <Q> I'm pretty sure that has to do with reflections especially at night. <S> If you ha...	Window glass reflects a certain amount of light, like a mirror.
Is it possible to accurately measure airspeed without pitot tube? This is a follow-up to my previous question: How does this IMU work and how to convert its output into meaningful information? for which many people asserted that I need a pitot tube and a static port in order to calculate airspeed and pressure altitud...	A pitot static system measures indicated airspeed which is the best indicator of things like when a stall will occur (at the slow end) and when the tail will rip off (at the fast end).
How serious is an impact like the 10/2017 Delta Airlines suspected bird strike? Recently, there was an incident where a Delta Airlines charter flight carrying the Oklahoma City Thunder basketball team was struck by an "unidentified object". Delta's official statement claims that Delta flight 8935, operating from ...	While a few incidents make it to mainstream news from time to time, bird strikes are a common occurrence in the aviation industry. It is an unusual situation, but not a dangerous situation if the pilots handle it properly.
What is the exact definition of Taxi Time? I found some definitions on the web, but they weren't same. Some resources mentioned it is sum of the times the aircraft is moving on the ground with its own engines. Some defined it as the time between chocks-on and take-off. <Q> As always, the definition depends on the cont...	Taxi time is the time the aircraft spends in movement or holds on the surface of the airport, prior and subsequent to flight.
Is it allowed to launch powered paragliders from national parks? I'm new to the sport and can't find a written answer. I've been told by local PPG pilots that it is illegal to launch from state/federal parks. I live near Johnson's Beach, Gulf Islands National Seashore and was told by the officer at the gate entrance: ...	The general rule in the US is that the FAA regulates where you can fly, but not where you can land or take off.
What are the names of the vehicles to provide assistance to aircraft during the turnaround? During the turnaround many vehicles support the aircraft on the gate. What are the name of those "vehicles"and their purpose? <Q> The most common vehicle seen is the tug . <S> source source <S> Tugs are multipurpose tra...	The vehicle is usually called a ground tug.
What would be a technical or slang term for 'in the air'? I'm writing a sci-fi story involving aircraft and space craft. I'm struggling to get the terminology right for referring to a pilot being 'in the air' either on a mission or a training exercise. I have a feeling there is a phrase for this but I'm struggling to t...	Mostly when a pilot is busy in flying, the phrase used it in the air .
How to slow down a seaplane on water? A seaplane cannot use brakes to slow down, like a land-based aircraft. So how does one slow it down? I am asking this in the context of landing, taxiing, aborted takeoff etc., as long as the plane is on the surface of water. I imagine a few possibilities: Land on a really long ...	In order to slow down the airplane even faster, you can perform aerodynamic braking , by using your elevators to disrupt the flow of air and hence increase drag in a controlled manner to slow the airplane down.
What was the first flight instrument ever used in an airplane? It's not magnetic compass, turn coordinator, stopwatch, wind meter, VVI, and airspeed indicator.I want to know what is the first flight instrument. <Q> It's the yaw string : <S> Picture: Source <A> The Wright Flyer , arguably the first controllable a...	The yaw string dates from the earliest days of aviation, and actually was the first flight instrument. Early flight in conditions that disallowed landmark and horizon earth reference often used dead reckoning as a means of navigation.
4 Boeing 707 for $50,000. Is that possible? I'm helping a friend with an article on some issues in my country, mostly related to corruption. His English isn't very good, so here I go One of the cases he's analyzing is the sale of 4 Boeing-707 airplanes for $50,000 . These airplanes couldn't fly but according to public...	Old aircraft (and other large hardware, like ships) get auctioned off all the time.
What is the purpose of blades on a compressor? What is the point of having blades on a compressor. I heard on NASA that it alters the flow but how would this help. As the flow of a fluid increases, the pressure decreases, and vice versa. The rotors increase the speed of the air and descreases the pressure and the stato...	The rotating blades increase the velocity, but do not decrease the static pressure, becuase they are adding mechanical work (energy) to the fluid.
How does a combat aircraft handle the recoil force of a mounted gun? How is the recoil momentum distributed or countered for smaller aircraft or drones while using a mounted gun? Is there any hydraulic mechanism to counter it and how it is distributed across the entire body of an aircraft? <Q> In this case, the large a...	In case of combat aircraft, the guns are hard mounted on the fuselage (or wings, for that matter) so that the recoil force is distributed throughout the body.
Is the Airbus A380 a viable shorthaul airliner? What is the technical, mechanical and economic feasibility of using the Airbus A380 for short haul flights of under 4 hours in its 800 plus seat configuration? I'm talking about cost and economies of scale, frequency of repairs and service etc. <Q> I can't say if anyone ...	Compared to several other airliners (Boeing 787 ), A380 is less fuel efficient.
Why does ADS-B broadcast velocity? I just read on opensky-network (scroll down to the section "facts") that ADS-B transmits roughly as many velocity as position messages. Since the velocity of an aircraft can be computed from two successive position broadcasts, why is the velocity transmitted directly? <Q> The "pos...	The first is that the velocity information is available from the GPS receiver and is magnitudes more accurate than the position estimation, and happens at a much higher rate than the position estimations needed for a velocity estimation. In addition to the additional computation cost, the measurement accuracy also need...
Do airline transport pilot trainees ever fly a passenger-less aircraft? Do airline transport pilot (ATP) trainees ever fly an empty aircraft? Consider the example where a pilot is under training to operate a 777 . Would the pilot ever fly the real aircraft without any passengers? Or is training only limited to simulat...	But, earlier this year, there was a documentary by EasyJet, where they showed how their new pilots trained, and they had to go through a couple of touch and go in an empty aircraft before they started flying with passengers.
If my parachute fails to open, why should I aim for land rather than water? I was watching these 'what if' parachute failure videos on YouTube and everywhere they say do not choose water over land. Why should we not choose water and what happens if we land in water? One such video: <Q> A partial failure of a chute is...	If your parachute fails to open entirely you are almost certainly extremely dead no matter where you land, however occasionally people do survive. If you hit the water, it really doesn't matter whether it's hot water, cold water, saltwater, freshwater, mineral water, branded water.
What is the largest taildragger in history? Large, modern multi-engine airplanes do mostly have the 'tricycle' landing gear type. But it hasn't always be the norm. I remember at least one big plane with 'conventional landing gear', the German four-engined FW 200 'Condor'... But, was it the largest of them all...? <Q>...	If you are going by the wingspan, that would be the Tupolev ANT-20
Why do many stealth aircraft have a similar shape and design? I have been playing around on a bunch of programs with stealth planes and their general shape. I know that they are required to be flat and have some sort of special material/paint on to 'absorb' the radio waves. But I have been pondering about the require...	Briefly, the design of stealth aircraft aims to reflect the minimum possible amount of radar energy back towards the radar.
Why don't we see business jets with wingtip fuel tanks anymore? There is something I miss from the Learjet 35 (one from FS95/98) that I don't see any more:Fuel tanks on the wingtips!What happened to the wingtip integrated fuel tanks in the business jet industry? <Q> One of the main reasons wing tip tanks were used was ...	The use of supercritical airfoil s, which allow thicker wings for the same drag divergence Mach number , helped as well to make tip tanks superfluous.
Do the wheels of taxi-capable helicopters have power? There are many big helicopters which seem to taxi just as good as any fixed wing aircraft, for example CH-47. Do their landing gear wheels have power or they also taxi using thrust like their fixed wing counterparts? If they do have power, are the taxi controls di...	Helicopters using wheeled landing gear do not have a drivetrain providing power to the wheels, though they are equipped with brakes. The wheels do not have power - there is no propulsion system linked to the wheels, they just spin freely. Control taxi by adjusting the thrust control rod.
What is the purpose of extending one degree of flaps (perhaps with spoilers)? What would be the use of one degree of flaps? And is there any reason to use both flaps and spoilers combined? <Q> Normally, one degree of flaps in fact only translates to an extension of the leading edge devices (e.g. slats), trailing edge f...	The flaps ensure that the wing doesn't stall, the spoilers dump part of the lift and act as airbrakes to keep the speed under control.
Who decided which airspaces not to fly through and how? I was looking at some flight paths, and I noticed that while some airspaces are ignored by planes for "obvious" reasons, like the Ukraine - Russian border airspace. For example, this flight seems to purposely ignore the Ukraine airspace. But on the other hand, I...	In addition to permits, some countries simply don't allow planes registered in certain other countries to overfly them, period.
Why do we seldom see small unmanned aircraft with gasoline engines? Most commercially available FLYING WINGS (RC aircraft or UAVs) are battery powered. Why aren't there more with with gasoline engines? PS: Sorry I edited. The question is specific about flying wings configuration. <Q> Because electric is the best propu...	A large variety of R/C engines is still available, from single-cylinder two-stroke glowplug engines with less than 1 cm 3 displacement, to 4-strokes, multi-cylinder engines, mini turbines, up to a 1/4 scale Rolls Royce Merlin. For larger aircraft, the square/cube law means higher demands on power/weight ratio, and elec...
What types of fuel quantity sensors are used in an aircraft? How do they work? Can you explain the different types of fuel quantity sensors used in most recent aircraft? Are ultrasonic tank sensors used these days? How does an ultrasonic sensor work? <Q> From this PPRune forum thread , the Boeing 777 does use ultraso...	Ultrasonic fuel sensors seem to be prevalent in stationery ground fuel tanks, not in aircraft.
What is the difference between MIL-H-5606 and MIL-PRF-5606 hydraulic fluid? what is the meaning of PRF here and can you differentiate them visually ? <Q> About 25 years ago, there was a major effort to revise MIL standards and specifications. <S> The biggest change in MIL specs was to move away from a design or manuf...	In your case, MIL-H-5606 is the 'old' spec. PRF is from the MIL-PRF portion of the Performance Specification and is not specific to this item number.
What's the difference between orientation and position? In INS (Inertial navigation system) sensors, is there a distinction between the following? Orientation (heading, pitch and roll) Position (latitude, longitude and altitude) Is the orientation relative to a specific axis while the position is absolute? If yes...	Heading is the angle relative to a suitable earth reference, usually magnetic north or geographical north.
How do commercial pilots keep situational awareness of their current call sign? Air transport pilots operate flights with a variety of flight numbers, often with multiple flights in the same day. This means, as a result, the callsign that they are using changes as well. Also, according to this answer , sometimes the c...	Many smaller aircraft have a placard with the tail number affixed to the panel somewhere (like in this citation cockpit).
Is there a system where plane/heli auto adjusts prop pitch/mixture? This one is simple: is there a system that automatically adjusts things such as: Mixture (I Am bored of listening for engine sounds) Prop Pitch (I Hate auto adjusting "gears") So I can only spend time adjusting throttle ? <Q> There su...	The BMW 801 had such a thing, essentially a mechanical/hydraulic analog computer which allowed to automatically adjust prop pitch, mixture, supercharger settings and ignition timing, all with a single lever in the cockpit.
How does the nitrogen generation system in a Boeing 777 work? How does the nitrogen generation system in a B777 work and how does it differ from that used in a B787? Any diagrams will be appreciated. <Q> The 777 system <S> As RAC points out , "nitrogen-generation system" is somewhat of a misnomer. <S> All the system...	The 777 architecture is basically the same as the schematic that mike provides ; in fact, all bleed-air aircraft use pretty much the same system.
What is the smallest manned jet aircraft? In the movie Spy Kids (2001) , there is a scene where the characters board a small jet aircraft "built for one passenger". The aircraft is about 2 meters tall with a 3 meters wingspan, and features a single jet engine, air intake located below the canopy, and tricycle landing ...	The BD-5J is what guinness world records claims to be the smallest but it is larger than the Cri-Cri in its jet implementation If you want to count really experimental stuff the Martin Marietta X-24A lifting body has a wingspan of only 11 ft 6in.
How does the lift coefficient of an A380 change when flaps are extended? I would like to know the lift coefficient with 10 degrees of flaps extended. <Q> As mostly when questions are vague, the answer is: It depends. <S> If nothing else changes, the nominal lift coefficient stays the same. <S> A coefficient is refere...	In a wind tunnel where the aircraft model is fixed to a sting and the angle of attack is controlled, setting flaps will increase the lift coefficient by the difference in zero-lift angles of the aircraft with and without flaps, multiplied by the lift curve slope of the aircraft.
Is there a website with a list of all commercial airline incidents? I am looking for a website that contains a listing of all commercial airline incidents (under a sufficiently large definition of "incident"), by airline company. I assume that incidents that happen are logged automatically somewhere, and I presume that...	The Wikibase allows users to add incidents, providing coverage of many more small aircraft incidents but may be less accurate. The safety index for each airline they cover is shown on their website. Entries go as far back as 1999, but the items are intended to provide information on accidents and an overview of the typ...
Are there any models for planning aircraft placement in hangars? I work alone at night doing line operations (fueling, tugging/towing, etc.) and emergency services (police, fire and EMS) at my airport. When a pilot/customer comes in and wants to know if we have hangar space available for their aircraft, it would be nic...	In my old company, we have used a software called PathPlanner and looked at another one called Aeroturn to simulate aircraft ground manoeuvring.
How much computing power is needed to keep commercial and military planes flying? I've always wondered, what sort of computing power is needed to keep modern commercial and military planes in the air? There are many systems of a modern commercial plane (e.g an Airbus A350), that would need to be automated and controll...	Any processor capacity that can do the job is good enough, and is only the start of all the aspects that go into certifying an airliner including its systems.
When a typical commercial airliner flies overhead, what is the actual noise we are hearing? We're all familiar of the sound planes flying quite high overhead and you hear a faint drone, even when planes are lower to the ground you hear them scream at a slightly higher pitch, but what exactly are you hearing? I would g...	What you hear is low-frequency broad band noise that originates from turbulence behind the engines.
Why isn't the APU a standard diesel generator? Why isn't the APU a standard diesel generator? Jet-A and diesel are interchangeable (with the addition of a lubricant). So why not use a cheaper piston engine as opposed to a jet turbine? V.S. <Q> Weight. <S> Piston APUs for trucks are designed for frugal and quiet ope...	A diesel generator would have to power a separate air compressor to do the same, and that's more weight, and another thing to break or need service.
Why can a plane land in zero visibility conditions but not take off in zero visibility? After waiting hours for a flight departure delayed because of heavy fog, I wonder why planes can perform an instrument landing with no visibility, but cannot take off without a minimum visibility. <Q> Using a HUD, an airliner can ta...	It all depends upon the equipment the aircraft has board, the infrastructure at the airport that is landing on, and the regulations under which the flight is being conducted under. Not all airports have the taxiway lighting required for low-visibility (typically, below 1200’ lateral visibility) taxi operations.
Would an aircraft with no ailerons, no elevators and no rudders be safely flyable? With contrarotative propeller (or not, if twin engine), cyclic and collective blade control. Would such an aircraft be safely flyable, and how efficient would it be, assuming it can have perfectly smooth wings (and tailplane)? In case ...	Not sure about your reference to the skydiving Kamov, but the aircraft could glide down after engine failure while keeping enough RPM to control cyclic.
Why do some aircraft have symmetrical tip airfoils while others do not? On some aircraft, the tip airfoil is symmetrical, while others carry their root foil all the way through the tip. It would seem an aerodynamic disadvantage to have a non-symmetric airfoil at the tip since it is not making much (any?) lift. It does...	Good aileron effectiveness also requires an airfoil which equally produces positive and negative lift at low drag.
What is the "on condition" concept of aircraft maintenance? "On-condition" appears to mean that a component should be "fit until failure" or that the maintenance should only be performed upon failure of the component. This seems problematic. Can someone help me to understand why some components are handled this way a...	In simple terms, maintenance depends on the condition of the item, which can be determined by regular inspections, hence the 'On-Condition' term.
How come nobody survived Air Moorea 1121, yet other people have survived crashes from altitudes more than 90x higher? Air Moorea 1121 crashed from no more than 400 feet, yet people have survived far more awful disasters, such as UA232 or JAL123. <Q> I'm guessing you consider your examples to be crashes from "90x higher...	In airliners that really do crash from higher altitudes, there are no survivors. Air Moorea 1121 was unsurvivable due to the high G forces of the impact with the water. The impact G forces were therefore far less and were survivable for many of the passengers.
Can a small GA plane maintain level flight with a significant nose-down attitude? Consider a small, one- or two-seater motor GA aircraft, something like a Cessna 152 or similar, designed for level flight at roughly neutral pitch. It's certainly possible to fly such an aircraft in a nose-high attitude while maintaini...	A normal light GA airplane will not be able to fly level with a negative angle of attack , but it can fly level with a nose-down attitude if the wings themselves are pitched upwards relative to the aircraft fuselage
What is the maximum G load a 747 can withstand during an emergency course reversal? In an emergency course reversal, passenger safety first priority, to avoid say, a column of ash from a new volcano, what it the most G a 747 can withstand with an average passenger complement? <Q> It depends on how you define :withstand...	Civil aircraft certification requirements for airliners demand normal operations be possible up to 2.5g and down to -1g in clean configuration up to design manoeuvring speed, reducing above that speed. There have been accidents where design operational loads were exceeded which still ended with a safe landing.
What is the purpose exactly of a ‘Control Check’? I recently watched an Air Crash Investigation episode where Qantas flight 32 lost an engine shortly after takeoff. It was revealed that a stud pipe in a Rolls-Royce engine was made incorrectly, causing the pipe to snap and burst through the engine and the aircraft's w...	While a standard control check is done as part of a ground preflight to make sure that the flight controls work well enough to fly, a controllability check is an in-flight operation, performed either as part of a functional check flight or, more importantly, after the aircraft has sustained damage .
Why do airplanes use MAYDAY when in danger but ships send SOS? I thought SOS means "save our souls", but apparently it doesn't. But ships send SOS when in danger and they used Morse code. Why do airplanes use MAYDAY? <Q> The difference here isn't between ships and aircraft: it's between Morse code and voice. <S> T...	Spoken out loud, it's short, easy to send, and easy to recognise.
Who checks that pilots have their licenses? One weird thing came to my head In the ground, Every time you drive an 91 CRX SIR/Civic Si EM1 or ride an Honda Dirtbike There is an possibility of getting busted by the cops waiting in the temporary checkpoints But what about the air? Who will check (Non existent) licenses o...	I've only experienced being checked when there was an accident, and FAA was investigating I've asked this same question of pilots in the past and gotten rather comical responses, like "as long as you don't crash the faa doesn't care" and things of that sort.
Is it possible for a civilian to use a VORTAC station? Suppose you have a Cessna 208 Grand Caravan Amphibian and you want to use VORTAC stations on military bases (or somewhere else). Is it possible? Is it legal? <Q> Totally legal to tune it up & use it. <S> If it is a VORTAC, it will work just like every other VOR...	If there happens to be one located on a base you are certainly still able to use it.
Is it legal to fly under the Golden Gate Bridge? I recently had the opportunity to rent a plane and fly in the San Francisco Bay Area. While flying in the HWD/OAK/SFO area is challenging enough, when I spoke of my adventures of flying above Alcatraz and the Golden Gate Bridge, some of my fellow pilots asked me if I fl...	If you are found to have done this you will be sanctioned and potentially lose your license. It’s illegal under 91.13 and any FSDO inspector who found out you did a damn fool stunt On rare occasions pilots have flown under bridges and other structures as part of demonstration flying.
How to perform a "first principle" performance calculation? I am a PhD student on flight dynamics and control. This week I was given an assignment to do some research on methods of aircraft performance calculation. After some search on the Internet, I found that traditional methods depended on tabulated data on the air...	You could have a look in open source PC flight simulator software such as FlightGear, which has aerodynamics and flight dynamics models for both A320 and B737. The only way to properly do a „first principle“ calculation is by (numerically) evaluating the basic equations of motion found in flight mechanics text books.
Could a golf ball damage an airliner? Question Would a golf ball ingested into an engine, or impacting a windshield cause meaningful damage to a commercial airplane? The scenario below outlines that this is possible, but the principle question is: would it actually matter, as in, would it cause the same level of dama...	So I'd have to say, very unlikely, only to allow for the chance in a billion that the sliced up fragments of a golf ball might actually enter the compressor stage and cause a problem in one engine.
Why do aircraft piston engines consume so much oil? This question is related to single/twin piston engine aircraft. After flying in a Cessna 152 and a Piper Dakota I have noticed that they both consume a lot of oil. Oil check is an integral part of the checklist. Pilots carry extra bottles of oil in the back. Why is th...	But as far as aircraft piston engines go, they do burn oil because they lubricate differently than an automobile engine.
Are engines automatically stopped in an emergency landing? This answer made me wonder if engines are stopped automatically after an emergency landing as soon as one of the exit doors are opened. (...) if the engine is still running, you're about to run forward into the area where you're at risk of being sucked into ...	(Actually there is never a mechanism to auto shut down the engines - emergency or not.
Why do most radial engines use an odd number of cylinders? To help suppress vibration, most 'V' and 'horizontal' engines use an even number of cylinders as closely opposed as possible. Radial engines are well known for excessive vibration. For some reason they nearly always use a staggered odd number of cylinder...	An odd number of cylinders is required by the combination of the single-crank radial design, the four-stroke (Otto) work cycle, and the desire to keep the power strokes evenly spaced in time.
Does engine failure shut off the auto-pilot? After answering this question it got me wondering whether there can be a situation where a complete flameout of engines could cause a serious loss of control if the auto-pilot were to continue to try to maintain altitude despite the loss of power. If it did, presumably by ...	If you're in an idle descent, one motor failing wouldn't really change the flight characteristics of the aircraft, so in that case there's no great need to get rid of the autopilot.
What is the physical meaning of circulation found in Kutta condition? The Kutta–Joukowski theorem is applicable for 2D lift calculation as soon as the Kutta condition is verified. When this is the case, there is a circulation $\small \Gamma$ around the airfoil . My question is related to this circulation: What is ...	The simplest way to think of it is that airfow above the wing is moving faster than that below the wing, which gives the wing its lift.
What is this cutout in the Spitfire cockpit glass? This is a still from the film Dunkirk. I realise this is not a historical document, but I have also found a similar feature in photos of real Spitfires . What is the purpose of this? <Q> According to flight manuals, this allows the pilot to maintain a view on the outs...	Note the punch-out panel on the canopy cover, an early solution to the new problem of canopy misting caused by the rapid altitude changes possible in the Spitfire.
How did ww1 pilots handle G-forces? The wikipedia page on G-forces, https://en.wikipedia.org/wiki/G-force , lists that WW1 aircraft encountered 4.5-7g during dogfights. This made me wonder, how did pilots in the early days of aviation handle the g-forces? G-suits were not invented until 1940s. <Q> This interesting B...	It seems that little was done (or at least little was documented) during the first world war on this front as the first actual technique for G tolerance increase was not used until 1933 . Proper breathing, body position and flexure of the skeletal muscles in the legs and stomach combined with physical conditioning with...
What fighters have both 1 & 2 engine versions? Northrop originally built the F-5 "Freedom Fighter" (and T-38 "Talon") with two engines. Later it was re-fitted with a single F404 engine from the F/A-18, re-designating it the F-20 "Tigershark" to avoid confusion. The first F-5A and T-38 flights took place in 1959. [Adde...	The Republic F-84F Thunderstreak was a fairly normal early jet fighter, powered by a single Wright J65 turbojet engine.
How do I know my AGL altitude while in flight? I am about to start my PPL, still flying in my FSX. I have a question, let's say I am flying from airport A to airport B. Both airports are in G airspace and I would like to stay in G airspace and don't go over 1200' AGL to class E. Let's say I would like to fly at 1100'...	The best way that I know of to determine your en-route AGL altitude with no GPS, albeit not the most accurate, is by finding obstacles along/near your route of flight which have an MSL and AGL altitude posted on VFR sectionals.
Do airline pilots increase thrust when ordered to increase altitude by traffic controllers? Do airline pilots increase thrust when ordered to increase altitude by traffic controllers? Do they simply use flaps, the yoke (or joystick in the case of airbus) and the stabilizers without any increase in thrust. What is the...	The normal sequence for a climb is to enter a new altitude in the flight computer and then engage a climb mode on the autopilot.
Why do all airliners have life jackets? According to this question, life jackets are not mandatory in planes that do not fly over large bodies of water. However, I have never been on an airline flight without life jackets (and the corresponding safety demonstration). Why do airlines not remove the life jackets from ...	One possible incentive for airliners to go ahead and equip all aircraft with them is to take out any restrictions on the aircraft's serviceable zone that would be in-place if not equipped with life vests.
What is the lightest weight operational jet/turboprop fighter ever deployed in combat? Since the beginning of WWII there was been a trend towards larger fighter aircraft. In about 1960 the United States continued with larger fighters (F4, F100, F111, F15) but also started a branch of very small light weight fighters (F...	The MiG-15 is a good contender having an empty weight of 8,113 lbs and a maximum takeoff weight of 14,458lbs.
Is repeatedly pitching an aircraft up and down to help it lose its energy quicker a viable landing technique? Say a pilot "bobs" his aircraft's nose up and down. The rapidly changing AOA should generate more drag than if the aircraft were to fly straight at a constant pitch where the AOA shouldn't be significantly larg...	The issue you face here is that pitching will affect your rate of descent rather strongly, which is exactly what you don't want while you're trying to land.
What is the meaning of nose-art on the Tu-160 bomber? The BBC reports another Tu-160 interception on 15 Jan 2018 and it's clear that there is a large message painted on the side of the bomber. Looking at the Wikipedia page , it seems this style of nose-art is common among the Tu-160 community; the style is similar...	Probably these texts are the names of persons notable in Russian aviation (not necessary pilots).
Why don't modern heavy bombers have gun turrets? I know that for a period of time the B-52 had a tailgunner, but nowadays many heavy bombers lack any turret defense.Why? <Q> There are really two reasons. <S> Fighter tactics Fighters used to depend (heavily) upon getting fairly close to an enemy, and shooting it down w...	Modern fighters are usually armed with missiles, with which they can engage from far beyond the range of guns. First, fighter tactics have evolved over time, and second, the role of the B-52 has evolved over time.
What is the real impact of biofuels on aviation? I have seen tons of initiatives about using biofuels (like the ASTM D7566), but it is operative at large scale?, there is background info about demonstrative flights, but I don’t see a manufacturer or airline that is making use of the biofuel in regular basis. It is a v...	The "real" (or at least ideal) impact of biofuels in aviation is a reduction in CO2 emissions.
What kind of delay does the A320's fly-by-wire system add? More precisely, I am wondering if there is any kind of data on how long it takes between moving the sidestick and observing a reaction on the ailerons or elevator. I know that the physical control surfaces take time to move and, thus, I am only wondering about ...	Yes there will be a delay, but the delay caused by the control loop is really tiny.
Do fighter jets use elevators as ailerons? I saw jets in game using elevators to roll right and left, but I never saw them doing in real life. I was wondering if fighter jets actually use elevator to roll like they do in game. <Q> Yes. <S> The airplane’s flight control computer can command a roll using all primary an...	Yes, high performance aircraft prior to the F-15/F-16 era (1970) or so, had a real problem in that attempting to roll the aircraft using ailerons, when at higher angle of attack(AOA) would, because of Adverse Yaw , produce a yaw in the opposite direction, (Stick to the left would produce right Yaw), which, because of t...
Why are the character keys on the Flight Management Computer in alphabetical order? Regardless of which aircraft type and manufacturer, the character keys on any Flight Management Computer are always in alphabetical order, see image: From a human factors view, this is sub-optimal, so why? Where does this order come f...	The placement and form factor of these keyboards is not suitable for applying a classic touch-typing technique.
Do wingtip vortices really only form when airplane wheels are separated from the ground? My GA theory textbook (which covers fixed wing up to and including EASA PPL) has some suggestions on taking off and landing light aircraft soon after large aircraft (besides avoiding it, if possible), intended to reduce the risk fr...	Strictly speaking there will be some downward force generated by the wings, but the transition from wheels to wings is so dramatic that for practical purposes we can indeed state that wingtip vortices are only significant with the wheels off of the ground.
Do some right-handed pilots fail to use the left stick of an Airbus? After years of flying left-hand throttle and right-hand yoke (in the right seat), are there ever first officers who simply cannot transition to the opposite due to particular hand-dominance? As a corollary, are there any pilots who simply cannot acqu...	The more varied and different types of aircraft a pilot has flown, the easier this process is.
What experimental techniques should one employ during cruise flight to determine correct airspeed to fly for max range in a headwind or tailwind? Theory demonstrates that one ought to increase speed in an headwind, and decrease speed in a tailwind to achieve maximum range. A lengthy discussion on the theoretical solut...	You may make a list of winds and the corresponding best range speeds and have that list handy at the cockpit.
How do elevons work to roll a flying wing? I have an RC Flying Wing that uses elevons for control. To go up both elevons move upwards and the wing pitches up. Both go down and the wing pitches down. I’m OK with this. However, if I want to roll right, looking from the rear of the wing, the left hand elevon goes down a...	If one elevon goes up, and one down: the one going up will create a pressure downwards, the one going down will create a pressure upwards -->
Does the FAA maintain pilot records from before 1998? I have held a PPL with an instrument rating since 1999, and I am desperate to continue, but I lost my logbook. Is there any way to get records from the FAA about my total flying time? I contacted my flight school, but they say they don't have a record of me, so th...	Surely the FAA has records confirming that you are a pilot with an instrument rating, but they may not have your total times from 20 years ago.
What's the appropriate course of action if an airliner bounces 5-10 feet on touchdown? I regularly fly in a PC flight simulator, and I'm currently trying to refine landings in medium-to-large airliners in various weather conditions. A problem I've faced in some conditions while flying the 737-800 has been bouncing on ...	You may touch down again during the go-around, and that's okay, but you're better off aborting the landing & taking it around to try again, than to risk damaging the aircraft by trying to recover from a high bounce.
Would removing heat from the compressor and adding heat to the turbine increase a gas turbine's efficiency? Since a compressor compresses air, the air temperature increases due to P1/T1=P2/T2. When the temperature is increased it would be harder to compress - so would removing the heat from the air inside the compresso...	There can be a thermodynamic advantage (inter)cooling the compressor and pre-/re-heating the turbine.
Why does the B-52 outboard engine nacelle have a sharp change in shape? The outboard engine nacelle of a B-52 appears to have a change of shape too extreme for just blending to the center-line of the engine pod. Why is the B-52 outboard engine nacelle shaped the way it is? <Q> The B-52 was build in different versions...	The reason is the distorted airflow from spillage if one engine of a pair has to be shut down.

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