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Was I nearly involved in an accident? This is a while ago but it has been bugging me now and then. On September 11 2011 (yes exactly 10 years after 9/11!) I was flying Easyjet 3467 from London Stansted Airport (STN) to Copenhagen (CPH). Scheduled departure was 18:40 local time but the flight was heavily delayed (aroun...	The term you want to look for is not "accident", but "incident" .
How do pilots foresee turbulence? During a normal flight at cruise speed and altitude, amid the delicious airline meal and the enjoying a latest movie, all of a sudden the seat belt sign turns on. Then a few seconds later we enter turbulence, grab a hold of that half-finished soda cup and wait patiently for the bumps ...	Besides those methods, planes ahead of them will be able to report that they experiences turbulence so the pilots behind them can anticipate.
What is a running rabbit? My father used to work as an air traffic controller, and often I heard mention of a 'running rabbit'. Obviously, vermin on the runways of airports can be a bad thing, but I don't think he was literally talking about animals. <Q> Background <S> The Sequenced Flashing Lights are part of some ...	Running rabbits can also be a reference to primary targets appearing on a radar scope in a sweeping arc, often caused by radar interference from another radar or other spurious RF.
How much oxygen do commercial airliners carry? How much oxygen do commercial airliners carry? Is is enough for every seat to have a 20-30 minute supply, is it a percentage of total flight time (ie 10% of total flight time), or is there a compressor on board? I would assume the goal of the pilots during depressurizatio...	They would carry at least 15 minutes of oxygen, but how long it lasts depends on how many people are using masks.
What is the cable connected to a plane for? I've seen that airplanes are connected to some wire like in the picture. What is it's name and what is it for? <Q> This is important especially during boarding, when the cabin lighting needs to remain on for passengers to embark or disembark. <S> The GPU is also used to start...	This is a ground power unit (GPU) which supplies the aircraft with electricity while the generators or the auxiliary power unit (APU) are not running.
Where to find a waypoints/fixed points, navaids and airports database? I wonder if it is possible to download a database with waypoints, navaids, airports and airways between them. I've been working with AIP documents but it's difficult to get raw information from them and they only have information about waypoints. I...	OpenFlights ( http://openflights.org/data.html ): free DB of airports, airlines and routes.
Where can I find data tables for lift and drag coefficients of airliners? I'm teaching an introductory course in fluid dynamics and I'd like to show some "real" data regarding drag and lift forces on an airfoil. It is easy to find data on the geometry of typical airfoils, but I was not so lucky with $C_L = f(airfoil, R...	It’s a text book and as such not quite freely available, but Obert‘s Aerodynamic Design of Transport Aircraft has a lot of surprisingly accurate data (including e.g. 777 drag polars).
Why is a clock necessary for IFR? According to FAR 91.205 (d)(6) , one instrument required for IFR is: A clock displaying hours, minutes, and seconds with a sweep-second pointer or digital presentation. Why is it necessary to time things in the cockpit, or know the time? <Q> An IFR clearance may have a void or r...	Having the number of seconds allows the pilot to fly these maneuvers accurately. There are several reasons: For departure clearances.
How fast can an F-22 scramble? The startup process in many military aircraft is, complicated, to say the least. It takes a lot longer than most would think. An F-16 from cold is required to be able to scramble within 5 minutes if on alert (armed, fueled, and pilot ready), 15 minutes if not. I also know that during th...	If you maintain a plane on alert (expensive and time consuming), you could get it rolling inside of 5 minutes. There is no set time because there are too many factors.
Why don't airplanes have smoking cabins? Is there any airplane model that has a small lavatory-like cabin just for smoking? I have never seen any such planes and that made me wonder why this is? It would not take much more room than a normal lavatory, make it much less likely that someone will smoke in the lavatory re...	It's a fire risk and a small fire from some idiot disposing of paper in the ashtray could spread; it would be hard to detect such a fire early because you couldn't just put a smoke detector in the smoking cubicle. According to FAA regulations, smoking lit cigarettes or anything else that produces smoke or flame is proh...
Do lights on aircraft flash in a specific pattern? On a clear night, everyone can spot planes quite easily: they have flashing lights. I have noticed that the pattern seems different for different planes, and tried to find a meaning. What I saw so far is that they seem to have three lights that flash, two at the wing...	For an aircraft like an airbus, wing tips may have a different blink pattern because the manufacturer wanted it that way.
Why does the BAe 146 have higher maintenance costs than other comparable jet aircraft? In many discussion (1) (2) it is stated that the BAe 146 has higher maintenance cost and higher cost of operations in compare to other jets due to its complexity. Quoting IslandHopperCO (Reply 21): The PSA (then USAir) BAe-146s w...	BAe sold the 146 for very low prices, so the saved money could cover the more expensive maintenance for some years.
Why are piggyback launches done by dropping the carried aircraft and not by "fly-off" launches? Every air-launched aircraft I'm aware of, with the exception of the D-21 in combination with the M-21 carrier, has been launched by dropping it. Is there a reason why drop launches are preferred to "fly-off" launches from th...	Drop launches get you out of the wake of the carrier faster
Is there a benefit to having the motors for a multi-rotor copter on the top vs the bottom of the frame? There is a new quadcopter being launched on Indiegogo that has the quadcopter motors positioned on the top of the propellers as opposed to being positioned on the bottom. Is there any advantage to this or is it ju...	The impact is lower when the arms are on the air-intake side of the propeller rather than in the downwash.
Are there ever temporary flight corridors? A recent question on FAA handling of evacuations prompted me to wonder if there are ever temporary (emergency based) flight corridors set up by any of the governing authorities? For example, is there ever the airspace equivalent of one way highways set up for a temporary p...	You could argue that any time an aircraft is given a route which is not on a permanent air corridor, a temporary one is set up, and that if a controller gives several planes a similar route, that corridor is in use More sensibly, no - there's no need to, there's plenty of airspace in areas with no corridors, and even i...
Why did Air France retire Concorde? It was developed by British Airways and Air France in the 1970s as the first supersonic passenger/civilian airplane. <Q> Ultimately the cost of flying the aircraft was more than the revenue that it generated. <S> Even with the best safety record in airline history, the crash combin...	Airlines that operated the Concorde eventually lost money on most flights, and long term operations were simply not sustainable. The Concorde began a steady decline to retirement after the firey crash of Air France Flight 4590 which killed 113 people, and again suffered setback after September 11th, 2001.
Can a fighter jet land on a modified airliner? Imagine this scenario: A modified military 747 is flying at a constant speed and altitude. On the top of the fuselage there is a device like a helipad but with three holes to accommodate the fighter jet landing gear, when pressure is applied the holes close, locking the l...	Your design proposal with the simple platform on top of the fuselage would carry a high risk of a tail strike if anything goes wrong, so it is unlikely that this will ever be tried for real. As an addition to the projects described by Peter Kämpf, there was the Tip Tow project during the fifties where two fighters were...
Cessna 172/182: Should I set the tank selector to the R.H. tank after parking the airplane? The single-engine Cessna 172 and 182 aircraft models have a dual gravity-fed fuel system, where you can draw from both the LH and RH tank simultaneously in flight. I've heard it said that when you are securing the airplane afte...	My technique (which would apply to any aircraft that doesn't have dual tank feed) is to turn the fuel off when it is parked.
Can you flag down / contact an airplane with a handheld radio in case of emergency? A friend and I are going rim to rim to rim in the Grand Canyon this Wednesday. It's a 46mi, 20+hr "hike" with some very physically challenging sections. We are packing the minimal amount needed - meaning not too much extra in case of ...	Unless you have a perfect day, or you know how to construct the right antennae for your frequency and environment, you would be better off with a rented satellite phone than a transceiver.
Has a commercial airliner ever crash-landed in an ocean? They have rafts and life jackets on board and before takeoff, passengers are explained how to use that equipment, but have any evacuations ever happened successfully? <Q> Yes, commercial airplanes have landed or crash landed in water many times. <S> If I am not...	In 1993, China Airlines Flight 605 , a Boeing 747–409, ended up in water after it overran runway 13 ...
Why don't airlines provide smoke hoods? In Fire-involved Accidents and Incidents Reviewed , Rudolf Kapustin stated in 1993 that Nearly all aircraft accident fatalities that are not the result of crash/impact injuries are the result of post-crash fires and the inability to exit aircraft quickly, which in most cases...	But, now, you've increased the amount of oxygen within the plane's fuselage so the hoods might actually make the fire worse and all the people who would have died from smoke inhalation might just end up dying from burns instead.
How does one launch unmanned high-altitude balloons without posing a safety risk to aviation? How can people launch balloons privately (filled with helium or hydrogen) that reach the altitude of 30,000 feet? Isn't that a safety risk in the same way as geese? <Q> An aircraft could collide with the balloon itself (as des...	Unmanned balloons can indeed create a safety risk for aircraft.
Why are vertical stabilizers always at the rear of an airplane? Sharks and whales have them in the middle of their body, so why not planes? <Q> With sea creatures the dorsal fin acts as a keel providing the actual sideways force during the turn. <S> They remain level while turning. <S> Planes on the other hand bank...	By having it aft of the center of gravity, it will generate a side force that will correct out any undesired yaw.
What is the rule of thumb for land/taking-off on a sloped runway? Skyvector lists the gradient for KMCI as 0.3%. What is the rule of thumb for how large a gradient needs to be before you always take off downhill and always land uphill like they do at Lukla ? Assume winds are not a factor. <Q> What does your POH/AF...	It depends on wind conditions and other factors like the surrounding terrain.
What is the rationale behind "One engine - Two propellers" configuration? I stumbled upon a very unusual Russian amateur built ultralight: One engine, two propellers configuration My first impression is that it adds another useless layer of complexity and moreover it may involve some safety issue: I particularly thin...	Generally having larger propeller area for power improves efficiency and reduces noise.
Do fighter jet pilots ever use autopilot? I know that military jets have autopilot, but do the pilots actually prefer to use it? I ask this question because, unlike civilian airplanes, military jets are more likely to come in a situation where the pilot may have to take quick decision and leave the designated path for...	Using an autopilot reduces fatigue on long flights and frees the pilot to navigate, manage systems, and keep a lookout for threats.
For an FAA commercial license, can I use EASA/ICAO 2nd class medical? I have an FAA 3rd class and EASA 2nd class medical. On my EASA 2nd class medical it says "This medical certificate complies with ICAO standards". To obtain an FAA commercial pilot license, will I need to re-take the 2nd class medical by FAA standard...	If you just want to get the commercial license as a personal training/development achievement then you can use your existing third-class medical, but if you plan to use your new privileges then you do need a second-class one.
Is it OK to move a light aircraft by pushing or pulling the propeller? It's very common to see pilots moving a light aircraft by pushing or pulling on the prop, either because there's no tow bar available or simply out of preference or convenience. Is this a reasonable thing to do or can it damage the prop or engine in...	Pulling on a prop right beside the hub will cause no harm - that's where the propellor thrust goes anyway.
What types of wood can be used for making propellers? Early propellers were made from wood and they still are on some vintage/classic aircraft and reproductions. What types of wood are typically used to make wooden propellers? <Q> Historically , the following woods were used: Mahogany Walnut <S> Oak <S> Almost ...	Birch, maple, oak, mahogany or walnut are good choices.
What does feathering mean and how does it work technically? Before I ask "What does Feathering mean when it comes to Jet/Propeller Engines" I have to say what I think I know: Feathering jet/prop engines mean achieving a sufficient turbine rotation speed at which, the general functionalities such as VFG drives (elec), ...	Feathering means to align the propeller blades such that the pressure difference between the camber face and back face are almost equal and hence they produce no thrust or drag.
What happens to the spinning wheels of the landing gear after takeoff, before retraction? What happens to the spinning landing gear right after V 2 on takeoff? Are they automatically or manually braked to a halt before gear retraction? Or are they allowed to spin to a halt in the wheel wells? I am asking this questio...	Most aircraft have rubber brake pads (snubbers) fitted in the nose gear bay that stop the spinning of the gear once the wheels are retracted.
Can a weather balloon move horizontally? How does a hobby weather balloon control its flight path? Just it just keep rising straight up vertically, always at the mercy of the winds, being swayed side to side? Unlike a rocket/drone, it does not have an engine/motor that can be controlled remotely. So if I want the ball...	You cannot control this horizontal motion and the balloon is at the mercy of the wind.
Can fuel sloshing in the tanks cause a stall? Cargo planes secure their load meticulously and if it breaks loose, the result is sometimes catastrophic . However, how do you prevent fuel sloshing inside the tanks and causing the same problems as loose cargo? <Q> There are dividers (baffles) in the fuel tank precisely t...	Some fighter aircraft use a sponge-like mesh in their tanks which is very effective in breaking up sloshing.
How does skydiving flight cause shock cooling? While answering this question ( How can reducing power too quickly on a piston engine damage it? ), barit1 said that: Skydiving planes see a LOT of shock cooling, and they pay for it at overhaul time What exactly happens during a skydiving flight which causes a lot...	You'll find no mention of shock cooling in the Pilot's Operating Handbook.
Can a drone travel beyond the range of its remote control signal? In a hobby drone, is it possible to set up the autopilot so that the drone travels to a distance far beyond the range of the remote control device and then comes back to the starting point? When I see hobbyists flying drones , it seems the drone always h...	Depends on the programming of the drone - mostly if it contains code for autonomous operations. From a technical perspective, there's nothing preventing it.
Is it worth reporting that I saw a green laser being pointed at the aircraft as a passenger? I was on approach to Vienna yesterday evening when I observed two 2-second green laser flashes 5 seconds apart from one of the rear passenger windows of the B737 where I was seated being pointed at the aircraft. I'm wondering...	If there is a attack on the airplanes, it is important that it is being reported before it is too late. So, a call where you could explain what you have seen and give a opinion is your best bet, if they tell you off then hey, you've tried it!
Which airliners could survive an EMP pulse? The incredibly bad, postapocalyptic tv series Revolution begins with a mysterious event that causes all electrical systems to fail all over the globe. Even batteries don't work anymore. In the first episode, after the "event" airplanes immediately start falling out of the...	Well the key to an airliner (or any other vehicle) surviving a real EMP would be having engines and flight control systems that don't require any kind of computer assistance. B-52s have been shielded and actually have a lead lined curtain that the pilots pull across the inside of the forward facing cockpit glass. I've ...
Do ANR headsets affect pilots' perception of engine problems? ANR (Active Noise Reduction) headsets reduce the sound level to a pilot's ears by creating an interference wave that cancels out some of the environmental noise in the cabin. Some say that this reduces the pilot's ability to hear minor changes in the engine'...	Although its possible to detect engine problems audibly, I don't think that's the primary mechanism (except for engine out) by which pilots are expected to detect engine anomalies.
How feasible is it to use Smart Materials on aircraft? Smart or Shape-memory materials have been known for quite long. What factors/limitations are put on it for applications in aircraft? For someone who doesn't know much about its material properties, it seems quite good to have deforming wing or other parts and see...	The low number of cycles will either require frequent replacement of the shape-memory parts or a very limited structural life of the aircraft. They are extremely expensive to make and to process, so they have never been an economical alternative. Shape-memory alloys will only switch between two shapes, and intermediate...
Why does Chicago O'Hare have a penalty box? I was reading What information does a pilot have about aircraft operating on an intersecting runway? and noticed this on the map: ( airnav.com ) Why is a "penalty box" marked on the map? What is it? What is it used for? <Q> In addition to what vasin mentioned in his answ...	A penalty box is simply a holding ramp for planes that currently have no place to be on the ground.
Is there any reason to use only UTC standard time in aircraft and not GMT? Why are we not using the GMT time standard in an aircraft? Why is only UTC the standard on-board? <Q> UTC is in principle the same as GMT. <S> But for accurate applications there is a difference: <S> In technical contexts, usage of "GMT" is...	Saying "GMT" often implies either UTC or UT1 when used within informal or casual contexts. Atomic clocks around the world are coordinated to keep UTC.
Do some light sport aircraft have clipped wings to lower their cruise speed? Light sport aircraft may have a max airspeed in level flight at MCP of 120kts . I have heard that there are some light sport aircraft that have had their wings clipped in order to have a lower cruise speed. But why do they clip the wings to...	A plane that already has very low stall and cruise speeds, but it pushing the max gross weight might be made to fit the light sport limits by clipping the wings.
Do any ejector seat designs include controllable thrusters? Are there any ejector seat designs with built-in thrusters, or boosters, which the pilot can deploy to maneuver himself out of, or away from enemy territory? A use case might be that after the parachute is deployed, the ejected pilot uses the thrusters to cha...	Yes, modern ejection seats have rocket motors, but they are only for propelling the seat away from the aircraft and upwards, high enough for safe parachute deployment .
Is there a legal maximum altitude? In the US, is there a highest legal altitude allowed for certain planes and does it depend on the plane? I heard from a sort-of-reliable source that the maximum is 45,000 feet but I haven't been able to confirm this. I ask since a plane I travelled in very recently was travelling at a...	There's no legal limit of how high you're allowed to fly by law: there's no law that says It is illegal to fly above X,000ft
What is the source for the flight data shown on in-flight entertainment systems? This question which claims that an altitude of 55,000 ft. was observed on a passenger's in-flight entertainment system on an Emirates B777 made me wonder: What are the normal sources of information for the flight data displayed on passeng...	Their are different kind of data transmission buses like ARINC which transmit that data then the required data is fed to IFE system through a protocol but most crucial data like data coming from Weather Radar etc is kept for Pilot usage and is displayed on the cockpit display panels.
How fast can fuel be siphoned out if you leave the cap off? It is a dreaded scenario; forgetting to secure the fuel cap. I understand the low pressure area generated above the wing will siphon fuel out of wing tanks, how fast would this happen in a smaller GA airplane with wing tanks (something like the Cherokee perha...	I was once passenger/safety-pilot in a Cessna 150 where the gasket between the tank and the wing skin had failed. When doing slow flight, the pressure above the wing was so strong that it would start to ooze fuel from the cap.
Why don't airlines have in-flight video recordings like buses do? That way we could study plane crashes more closely, or terrorist hijackings, or resolve passenger disputes. Even buses in Ecuador have video cameras.(WARNING: shocking video) <Q> Many airlines do in fact have inflight camera feeds for Cabin surveillance...	For a specific example, Emirates Airline employs the Cabin Video Monitoring Systems (CVMS) across its fleet of Airbus A380 aircraft. In the case of a terrorist hijacking, having video wouldn't really help much.
Why does "no aircraft cross directly over the pole"? This is from the last paragraph here : ... no aircraft crosses directly over the pole – the closest route is 60 nautical miles (nm) away. User Michael Shen of York University asked this originally under the article. <Q> This article from AA (titled "Over the T...	At the Pole, an airplane’s compass changes from a due-north heading to due south, and that change of course could potentially lead to problems with earlier-generation autopilot systems.
How does an airliner deal with cabin altitude at an airport above 8000 ft? There are a number of airports above 8000 ft altitude . FAR 25.841 states: Pressurized cabins and compartments to be occupied must be equipped to provide a cabin pressure altitude of not more than 8,000 feet at the maximum operating altitu...	I imagine that airline crews would pressurize for passenger comfort until descent, and then gradually bleed away cabin pressure until touchdown.
Why are passenger seats not facing backward on an airplane? In the event of a crash, facing backward sounds much safer: Forces are applied on a much larger surface (your whole back is in contact with the seats, instead of just a seatbelt and maybe the opposite seat) Most passenger are already in position in case of...	It seems that backwarding seat make passenger feel not good. Backward-facing seating will only help in the fraction of cases where deceleration loads are too high for a forward-facing person, but low enough to make the crash survivable.
Is there a difference between how commercial jets and GA aircraft use airways? In the answer to this question about why people use airways, one of the commentors pointed out that GA aircraft often use airways in a different fashion than commercial aircraft. I couldn't tell from context why this is true though. Is i...	In Europe, some airways are only available in certain flight level ranges, so a commercial airliner and a GA turbo-prop travelling from the same departure airport to the same destination airport could be travelling on different routes due to airway restrictions in place and the inability of one aircraft to climb to the...
Who should handle an emergency when there's both a certificated pilot and a CFI on board? While practicing for my commercial certificate in a T-tail Piper Arrow IV , I put the gear down on downwind, and one green light didn't come on. In the right seat was a CFII/Multi, who had over 1,000 hours but less than 10 hours...	both pilots should be handling any emergency that arises, each working to their individual strengths and expertise to ensure a safe outcome.
Why doesn't frost form on a moving airplane? When I was a young student pilot, long before the FAA prohibition on polished frost went into effect, an instructor left a six-inch square of frost on the wing to demonstrate how fast it would disappear after takeoff. Sure enough, we hadn't even reached pattern altitude and...	In flight, the high speed air flow over the aircraft keeps its skin at essentially the same temperature as the air so it doesn't drop in temperature the same way. When the air is not saturated with water, ice will sublimate.
What's the right way to take a dog in a small plane? I would like to take my friend and his dog for a flight. What's the safest way to take the dog? and what's a good way to protect the dog's hearing? <Q> My wife and I have a small dog that frequently travels with us. <S> We place her in a soft-sided kennel that stra...	If the pet is large and cannot fit in carrier which can in the plane, a pet harness that can be secured to seat belts or seat belt attachment points can also be considered. As for the hearing part, a company called Safe and Sound Pets makes a product called Mutt Muffs .
Why are movable rocket thrusters not used in airplanes? If an engine fails in a passenger airplane, why can't it have movable rocket thrusters in the wings to help safely land the airplane? <Q> Any time the question is "why don't we have..." , the answer is almost certainly in the trade-off between weight, maintenanc...	The advantage of rocket thrusters over conventional aerodynamic control surfaces is that they work in space.
Flying out from an uncontrolled field, should I contact approach or departure at the nearby control field? I am a new pilot who flies out of an uncontrolled field. When I depart and want to ask the controller for the nearby controlled airfield for flight following, should I contact approach or departure, or it does not...	For flight following, more important than picking between approach and departure frequencies, is to contact the TRACON on the frequency for the airspace that overlies your position.
Why use plywood to hold the bearings for the airbrakes on a fibreglass glider? The ASK-21 is mainly a fibreglass construction. However, the bearings for the airbrakes and their control rods are fitted into small pieces (some 10 cm wide) of what seems to be plywood molded into the fibreglass. The following picture sho...	Plywood is well suited for this task, while being lighter, cheaper and easier to build and machine than aluminum or fibre-reinforced plastics.
What safety features prevent jets sucking in ground staff or equipment? There have been some gruesome deaths involving ground staff being sucked into jet engines, presumably because the engine thrust was set well above idle. Are there safety features (besides prudence on the flight deck) that are designed to mitigate t...	A special indicator light will be on when the engines are about to be started/are running (for example: the Anti-Collision light for the B737, and the Beacon light for the A320.)
Why are flight recorders generally located in the tail? Is there a particular reason why FDRs and CVRs and associated similar bits of equipment are kept in the tail section of a plane? <Q> When an aircraft is crashed, the entire front of the aircraft is expected to act as a crush zone . <S> By placing FDRs and CVRs ne...	By putting the FDR and CVR in the back the acceleration is reduced allowing for a higher probability of them remaining intact.
Is there any limit by FAA on the age of aircraft to be operational? Is there any restriction by FAA that one can not fly a plane older than 'X' years? If someone is maintaining an older plane (e.g. from 1990s), are there any regulations which prevents or restricts that person to fly that airplane? I am interested in ...	As such there is generally no regulatory restriction on airframe age , though there may be other applicable restrictions (or recommendations) depending on the aircraft.
Why doesn't an airfoil rotate? As far as I understand, two of the reasons how an airfoil generates lift are Coandă effect and downwash . However, if there is upwash near the leading edge, why isn't an airfoil rotated by the two forces (upwash at the front and downwash at the back of an airfoil)? <Q> It does rotate. ...	Because the horizontal stabilizers provide a counter force to the plane in its entirety so the pitch remains stable.
Are the military tilted-thrust aircraft in the film Avatar feasible? As full-scale aircraft or as models / UAVs / drones? Is anyone working on making these real or are they fundamentally flawed designs, or needing new materials to be invented? <Q> I presume you're talking about the fictional Aerospatiale SA-2 Samson ...	Yes, they are certainly feasible. I don't believe there are any full size models, but the Osprey is "close enough" to prove the concept.
Can seaplanes land on normal airfields or in a marsh or muddy area? I know there are some amphibious planes which can land on both water and land but how different is the their landing in comparison to that of a normal small aircraft? Also, if seaplanes needs to go into some marsh, will that work for them? <Q> Back in...	A pure seaplane cannot land on a normal (land)
Do helicopters have trim? How does it work? I recall having read somewhere that “helicopter in forward flight behaves just like a badly trimmed airplane”. So I'd like to ask: Do helicopters have trim? If so, how does it work? And is the helicopter stable when properly trimmed? <Q> It depends on what you mean by t...	The amount of trim, in the case of Robinson helicopters, is not pilot adjustable, but it is a trim setting, technically speaking, which is separate from the friction settings, which helicopter pilots can/do use in the same way fixed wing pilots would use a "trim". Some will use a "trim" function to hold the cyclic or c...
What are the ways to keep the birds away from airfields? I know bird strikes are a major issue for many airports, and that measures are taken to keep birds away. There are some obvious things airports can do like not to have any stray garbage, food, etc. in the open, but I'm sure other less obvious methods are also use...	Remove sources of food, such as seed-bearing plants, use insecticides to eliminate insects as a food source, remove bushes and plants that can be used for nesting The use of visual devices (lasers) or audio (sonic cannons, recordings) to scare away birds Trained falcons, dogs, or other predators to make the airport inh...
Do flight tracking websites also track non-commercial and defense aircraft? Many flight tracking websites have the data about almost all the commercial airplanes in air. Do they have the data about the private jets and/or defense aircraft also and they just don't show that on the websites? <Q> As long as an aircraft tr...	Flight tracking websites, such as FlightRadar24 and FlightAware , generally track aircraft using publicly available ADS-B transponder information.
How flat does a runway need to be? I always assumed that big runways are flat (or more specifically straight: they might have a slight slope in either direction), but while watching some crosswind landing footage shot at Birmingham Airport I noticed that the runway looks really uneven, and based on the videos it look...	Landings and takeoff on uneven runways are not significantly more complex than on straight runways.
Do nacelles around aircraft engines help in reducing the engine sound? I know that the nacelles around the aircraft engines are actually a housing and are generally lightweight and have may components like inlet cowl, fan cowl, etc., but do they help in reducing the engine sound as well or are they just for housing? ...	A last noise reduction contribution to mention here is the capacity of the nacelle to contain the shrapnel from a failed fan blade.
How or when can the 250 KIAS speed limit below 10,000ft be exceeded? This arose out of a comments discussion in this question . The only airspace I really know is the UK. Here, a controller may issue a clearance to exceed the 250kt limit below 10,000ft for reasons other than minimum safe flying speed, e.g. to expedi...	Departures:It is extremely common to hear ATC cancel speed restrictions on departing aircraft.
What are the major hazards in operating a PT6 Turbine Engine? I am just in the process of doing a bit of study in the hope of doing my Basic Gas Turbine Endorsement in the next few months, and just wanted some feedback/comments/discussion on the major hazards associated with starting, managing and shutting down a PT6 T...	Overtemperature during start means that something is wrong with the engine.
How much "power" do ATCs really have? After reading this question about being cleared to go faster than 250kts in airspace that otherwise has a speed limit, I began to wonder how far can Air Traffic Controllers (ATCs) can bend the rules on an aircraft-to-aircraft basis? Is there a limit to what exceptions ATC can ma...	So in practical terms, ATC do have the ability to deviate from most of the usual procedures, but always within existing guidelines.
How is combustion flame maintained in the combustion chamber after igniters are switched off? During start phase of a jet engine, igniters in the combustion chamber create sparks to initiate combustion. As far I know, when the engine reaches self sustaining speed, igniters get turned off (this might be different (take...	Once the fire is lit (by the ignitors) it is constantly burning.
Are those devices allowed on a flight which create their own WiFi signals? I am going from Canada to Mexico but I don't want to be dependent on in-flight entertainment. Thus I got seagate wireless plus so I can stream to my iPad. I couldn't find any policies I can use this device during flight or not. At very least I...	So, in order to be able to use wifi on the airplane, you need to have, first the airplane modern enough and the airline shall be authorized by the authorities.
When is runway slope most important? Based on this other answer , a new question arose.When is runway slope most important, at take-off or at landing? Or is it equally important in both flight phases? <Q> I would argue that it is most important on takeoff. <S> The reason is that most planes require more distance for t...	Runaways are always thought to have enough visibility for the pilot when trying to land of take-off.
Why did this Cirrus deploy the parachute while ditching over Pacific Ocean? In this incident near Hawaii , a Cirrus SR22 had fuel problems and deployed its airframe parachute . My question is why did the pilot deploy the parachute rather than perform a "normal" ditching procedure in the ocean? For reference, here's...	If pulling the chute would mean landing in water or dangerous terrain but gliding would mean reaching land where a forced landing was reasonable I'd probably opt for gliding.
Why did most airliners have black noses in the 60's and 70's? Here are a couple of examples: <Q> Under the nose of modern airliners is weather radar that helps the crew to see and avoid hazardous weather conditions. <S> This is required by FAA CFR <S> §121.357 for transport category aircraft. <S> The radar signal wou...	The fuselage within pilot's view is painted dark and of matte finish to reduce the chance of any glare that might obscure pilot's vision.
What is the MEL (minimum equipment list)? What is a minimum equipment list for an aircraft? How are MEL and MMEL related? Who creates the list, and how do they decide what is on it? <Q> As mentioned here : A minimum equipment list is a list of equipment that must be installed and operable for the aircraft to be con...	A MEL (Minimum Equipment List) is a 'custom' document generated and approved for a specific airframe serial number, or a group of aircraft that are identical (fleet).
Why do we use pylons to mount the engines on jetliners? This question focus on jet airliners. The De Havilland Comet's engine were mounted inside the wing, the Concorde's engines were mounted underwing (as many jet engines) but without pylon. It seems jet airliners' engines are now mounted on pylon. That assumptio...	The real answer: pylons make engine maintenance easier and are a more practical solution for current high bypass turbofan engines.
Have there been any 'proper' field trials of Automated Air Traffic Control? Have there been any 'proper' field trials of Automated Air Traffic Control? Specifically, something that has been tested on larger aircraft and has come beyond the drawing board. By automated I'm implying that all decisions on movements are ma...	There have been a few small scale, limited and tightly controlled trials, but nothing over any significant time frame, involving a significant number of aircraft, or even involving aircraft in "normal" use.
Do we have a unit to measure turbulence? Do airplanes have any way to quantify the turbulence like if shakes are there or the some kind of air drift is happening every parameter of these have some units but do collectively there is any such unit which can quantify the turbulence? <Q> EDR can be calculated from availabl...	Turbulence can be quantitatively expressed as Eddy Dissipation Rate (EDR).
What is the minimum thrust needed to takeoff? In passenger airplane how much thrust is required to takeoff? What factors does it depend on? <Q> This is quite a bit higher than the minimum flight speed, so you should add something to quicken the acceleration to this point. <S> Also, you want to climb eventually, so you ...	You need at least enough thrust to keep the airplane flying at the speed of minimum drag.
Why aren't there more helicopter aerobatics at airshows? I enjoy watching RC helicopter stunts like these . Many RC pilots are very talented, executing barrel rolls and other inversions. How come we don't see these kind of displays at airshows? <Q> There just aren't many helicopter aerobatic pilots around. <S> The...	As for why you don't see a whole lot of... less ambitious acrobatic flying in helicopters, it's possible that certification is an issue.
What would happen to the rudder on an A320 if both FAC systems failed? What would happen to the rudder of an A320 if both Flight Augmentation Computer (FAC) systems completely failed during mid-flight? Would the auto pilot immediately pass control back to the pilots or if they failed would that be it? Would it be impo...	Computer-generated rudder commands for yaw damping and turn coordination are added to the mechanical signal from the rudder pedals, but in the event of a two-sided computer failure the rudder can still be controlled.
Can spatial disorientation in low visibility situations lead a pilot to fly upside down? In this comment it's mentioned that pilots in instrument conditions may wind up in a situation where they're inverted due to spatial disorientation , and be completely unaware of it until they fly out of the cloud. Is that real...	So yes, it's absolutely possible for the aircraft to end up in an extreme attitude very quickly and easily: in this case the pilot just looked away to set the autopilot.
How Earth's rotation affect flight times? How much does Earth's rotation affect flight times in going East or West, and how could you calculate if zero winds? <Q> It does not affect as much as one would think. <S> The atmosphere moves along with Earth's rotation. <S> An airplane taking off from one place on Earth has...	If you ignore wind and side effects such as the Coriolis effect, the earths rotation has no effect on your journey time since you and the craft you are in must move at the same speed within the same frame of reference, relative to any given observer, together.
Would TCAS ever issue a "climb, climb!" RA that would stall a jet with a low airspeed? As a for instance, let's say there are 2 jets going at low airspeeds (close to $V_S$) that get too close to eachother and a TCAS Resolution Advisory callout is announced. Would TCAS issue an RA to order one of the jets to climb, res...	There is no more risk of stalling an aircraft from a TCAS alert than from being instructed verbally by ATC to climb to a higher altitude for traffic avoidance.
Is it possible to do a barrel roll in a large aircraft like a B737? Can the bigger planes like B737 do barrel rolling kind of stunts like fighter jets do? I'm sure if it's full of passengers or cargo it would be very difficult and dangerous, but is it possible with an empty aircraft? I remember an All Nippon Airways ...	Yes, it is possible. Yes, it has been done before in an even larger aircraft, the Boeing 367-80, very famously by "Tex" Johnston on August 7, 1955 .
Why are geodesic airframes no longer produced? Why are geodesic airframes no longer produced? Do they cost more than conventional structures? Are they not as strong as conventional structures? I assume it is insufficient cost benefit ratio, but how does that work out? Wellingtons under construction. Photo: Roya...	Geodesic frames are good in transferring both bending and shear loads.
Why don't airliners have a navigation GPS as back up in case of a pitot tube malfunction? Why don't airliners have a navigation GPS as "back up" in case of a pitot tube malfunction? Aeropero 603 and Air France 447 plus many other im sure, could have been saved if these aircrafts would have had a simple Navigation GPS a...	Airliners do generally have GPS receivers, but GPS doesn't give you the information that's needed in this case.
Why do passenger aircraft have the little airjets over each seat? I never turn them on, but I do turn them off if I notice them. Is this a relic from the age when people lit up next to you and you wanted to blow away the smoke? The system must weigh almost a ton on a large aircraft and seems pretty unpopular and hard t...	Also a common "cure" for airsickness is fresh air -- blowing cool air over someone's face will often help with symptoms of motion sickness, and may prevent a nauseous passenger from actually vomiting. Make the passenger feel he's in control of something.
Are there international standards to Air Traffic Control procedures similar to US standands? In regards to air traffic control, FAA Order 7110.65 is the standard for policy and procedure in the USA. Do other countries use this also? Is there an 'international standard' for air traffic control? If so, are there any no...	Every country in the world generally operates from their own manuals. The International Civil Aviation Organization, ICAO, also has a standard that it recommends, and many countries have copied.
Should I log flying lessons from the start? I've recently started taking flying lessons and was wondering if I should begin logging my flying hours immediately? I'm aware there are minimum hours for each license certification, so I'm assuming I should be noting down my flight time right from the start but my instructo...	Yes you have to log your flight time when you train for a license! Yes, you should be logging from the start.
Can you fly an airplane at a 90° roll angle without losing altitude? I've seen this answer to the question about flying upside-down, but tilted by 90°, there should be no surface creating lift (except maybe the vertical stabilizer). <Q> It depends. <S> As always. <S> If thrust is high enough, why not? <S> Knife edg...	MANY aircraft can sustain flight in horizontal flight with the wings 90 degrees to the ground.
Why does the Mitsubishi MU–2B have its own SFAR? The Mitsubishi MU-2B has a very long & detailed SFAR 108 that details the trained and currency requirements for anyone who wishes to manipulate the controls of the plane. I'm wondering what incidents or accidents and unusual handling characteristics required a Special ...	Same with the other SFARs, there's usually been a rash of incidents outside of what's normally taught for the category/class, that requires special or additional training. Various design issues I've heard are related to it, from possibly overpowered engines, to short wings.
How much jurisdiction does the FAA have over military aircraft? The FAA controls just about everything about civilian aircraft in US airspace in terms of regulation, certification, flight rules, etc. Do they have any authority over military aircraft beyond requiring military flights to communicate with ATC for safety a...	Military operations can exempt themselves from the FARs (as a matter of practice they don't : When operating in the US National Airspace System they follow the same operational regulations we do, but as a matter of regulation they're subject to the military's rules for airworthiness, maintenance, etc.).
UAV project in aerospace department I am 2nd year PhD student in Physics. Can you think of any UAV project which won't contribute to army? UAV designing is a career of my dream, but I want to serve the greater good. However, all advances are developing in military field. <Q> But guess what: Development took much longe...	One would be the Aurora Flight Sciences Perseus , which started as an unmanned instrument carrier for flights into the south polar vortex, in order to study ozone depletion.
Why would a commercal flight circle while enroute? While selecting random flights to learn about FlightRadar24 , I came across AC7311 flying from Toronto, ON (CYYZ) to Indianapolis, IN (KIND) , and saw that it flew a couple of circles southwest of Lima, OH (near KAOH ). What are some of the reasons Air Traffic ...	Bad weather can reduce the rate at which an airport can accept aircraft, meaning some will have to enter a hold. It's called Holding Pattern .
What is the maximum altitude a skydiving plane can fly? Is there a standard maximum altitude which skydiving planes can fly? I am mainly asking about the sports activity, not military parachuting. <Q> Qualifier: I am a master parachute rigger and taught sport skydiving for 10 years. <S> Standard jump altitude is 12,...	As paul mentioned, "standard" altitudes for sport skydiving facilities near sea level are in the 10,500-13,500 AGL range.
In calm winds, which runway should I select at an untowered airport? In calm wind situations, approaching an uncontrolled airport with no other aircraft reporting on CTAF, which runway should I select that would cause the least safety hazard? Especially at an airport with one runway, I don't want to set up to land hea...	If the pattern is empty my personal practice is to pick the approach to the longest runway with the fewest obstructions, and ideally one that doesn't overfly residential areas (where it's practical to avoid doing so).
How do I keep coordinated on a windy day? I've noticed on windy days that keeping the aircraft coordinated can be difficult -- the ball will tend to bounce back and forth in the turn coordinator, and I will find myself "chasing" it with the rudder pedals. Any advice for managing this situation? At cruise it doesn't...	Its enough to glance at the ball each time you enter a turn and each time you return to straight flight, and make a gentle correction.

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