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Can commercial airliners fly over hurricanes? When Patricia was making landfall yesterday I opened up Flight Radar 24 to see if there were any planes flying around or near it. As I had expected, there were a couple of storm watching planes near the hurricane, but what surprised me is that there were some commercial fl...	They can fly through the top (or even the base) of the hurricane in an emergency situation and nothing will happen, see Flying through a hurricane (YouTube) , but it is not preferred to expose the plane to such vibrations if better options, like going around the hurricane, are available.
Why is the rear seat ejected before the front one? On aircraft with 2 crew placed one in front of each other (tandem) equipped with ejection seats, the rear seat is ejected before the front one (described here for the F-14 ). Why is the rear seat ejected before the front one? Is an aircraft without ejection seat (...	This is done for a few reasons: If the pilot seat is ejected first (or both are ejected simultaneously), there is a possibility that the pilot seat may collide (as it will be dragged backwards due to wind force) with the copilot seat or damage the (rear) canopy during ejection.
What was the first plane that allowed walking during flight? What was the first plane that allowed crew members and/or passengers to stand and walk during flight? P.S. I mean walking inside the cabin, as part of normal operation intended for by the plane designers, not walking outside the plane, on wings and other ac...	Early airlines like the Short Empire 1936, or the Boeing 314 Clipper 1938, most likely saw regular walking around on their long flights but these still post date the HP42. Sikorsky Russky Vityas (picture source )
Why don't helicopters prefer shorter rotors with more blades? My understanding of helicopters is that, despite theoretically increasing efficiency, longer blades are worse in practice than short ones in every respect (except, perhaps, cost): Longer blades are more prone to vibration and resonance dynamics, if f...	In general, lesser the blades, more efficient the system- as it changes the momentum of more air mass i.e. accelerates more air by a lesser amount (
Can you breathe with a drop down mask under water? Say a passenger jet lands in the ocean. Could the captain being the last person to get off the jet use the drop down dry chemical oxygen generators to breathe while checking for passengers? I know they are flimsier so depending on depth they would collapse. <Q> No, you...	So yes, if contained it could provide oxygen under water (provided the reaction did not react with the water).
Can the V-22 autorotate? Can tilt-rotors like the V-22 execute an autorotation landing? If so, are the conditions under which that would be possible (and survivable) different from a helicopter? <Q> The V-22 rotor disks are much lighter than a helicopter's. <S> There's little energy available to use to cushion a landi...	The V-22 is a tiltrotor and does not rely on autorotation for a survivable power-out landing. The manufacturer's position is that autorotation was never part of the specification.
Are control inputs different during autorotation? My understanding is that during power-off autorotation the main rotor is still coupled to the tail rotor, and the flight controls execute the same functions as during power-on flight. Two questions: Do any (heavy) helicopters have power-assisted controls? If so are ...	The primary difference is that rather than controlling lift and power, the collective controls rotor speed since increasing pitch increases the angle of attack which increases lift and therefore increases drag, slowing down the rotor. During autorotation, the coupling between the swash plate and the flight controls is ...
Why does the co-pilot sometimes keep a hand on the throttle as well as the pilot? In this YouTube video of a takeoff and landing in a Dash-8 , you can see the pilot, while landing, keeps his right hand on the throttle levers. The co-pilot keeps his left hand at the base of the throttle levers during this time. This h...	It also guards against inadvertent throttle retard due to failure of the seat adjustment slides during the catapult shot( S-3 Vikings,E2C Hawkeyes,C-2 Greyhounds,etc)
What are the differences between air brakes, spoilers and lift dumpers? So many people use these words interchangeably, but after a little searching on Google, I found they are not quite the same thing. All the links I read explain things in a misleading way which pushed my confusion even further. I'm looking for a si...	However in general: Airbrakes and speedbrakes are interchangeable terms; just large reinforced panels which can be extended out from the aerodynamic envelope, creating a lot of parasite drag. Spoilers and Lift Dumpers are, again, interchangeable terms.
Why do police helicopters always fly in circles? Why do police helicopters always fly in circles while news helicopter hover in one spot? Is it to avoid criminals opening fire at them, or is it because there is a difference between the two types of helicopters? <Q> Police helicopters don't always fly in circles. <S> ...	It might be that the police helicopters in your area can't hover at the heights they work at, with the weight of their usual equipment.
What is the difference between a nacelle and a cowling? I see these terms used almost interchangeably. To my understanding they both refer to the covering of an engine. Is there a technical difference between the two? <Q> The definition of a nacelle refers to the housing of anything on the outside of an aircraft. <S>...	So a nacelle refers to the whole covering of an engine that is outside the plane, typically on the wing.
What is the ultraviolet signature, if any, of aircraft and jet engines? The Wikipedia article on the FIM-92 B variant of the Stinger Missile says: In this version, the infrared seeker head was replaced by a combined IR/UV seeker that utilized rosette scanning. This resulted in achieving significantly higher resista...	To answer the question directly: The UV signature of the aircraft itself is practically zero except for the reflection of the UV part of sunlight, and the active UV emission of a jet engine is extremely low and concentrated around its exhaust when seen from behind. You're correct that IR/UV means Infra red/Ultra Violet...
Can any aircraft adjust the wing dihedral in flight? Are there any aircraft that can mechanically modify the dihedral angle of the wings whilst in flight? Would this solution give any advantage? <Q> There was one, and it did it to increase directional stability at supersonic speed. <S> I am talking of the North Americ...	In general, any aircraft will have its dihedral modified in flight due to the aerodynamic loads, though it is more pronounced in case of aircraft having high aspect ratio and slender wings like the Boeing 787.
Can people who suffer from motion sickness become pilots? Suppose a person suffers from motion sickness when flying, but wishes to become a pilot (let us say, with the eventual goal of flying for a major commercial airline). Is this possible? Is motion sickness a medical disqualification for a pilot's license, in ma...	So it all depends on the person's individual situation, but it is definitely possible to get a medical, even if you require medication.
Can an aeroplane ever be so far away from an airport that it cannot land? Hypothetically, if an aeroplane with two engines is flying over the ocean and is far away from land, is it not quite likely (but still not very likely at all), that one engine fails and it cannot get to an airport before fuel runs out? Are the...	Operating an aircraft carries a remote risk to land on unprepared ground.
Is it possible for more than one airplane intercept the ILS at the same time? I was watching a timelapse video yesterday of the approaches on a busy airport (I don't remember which one), and I saw that about 3 or 4 planes were lined up and descending at the same time (they were far from each other) and that got me th...	Yes, since the ILS is just a set of radio signals emitted and received by aircraft, there can be more than one aircraft established on localizer and glidepath.
Do commercial aeroplanes use ABS to brake? I have read that the wheel brakes on an aeroplane are by for the most efficient means of stopping it. I was wondering whether in low grip situations, such as in rain or snow, an ABS (Anti-lock Braking System) system is used to ensure the wheels do not lock. If not, why is this...	ABS was first developed for aircraft use in 1929 by the French automobile and aircraft pioneer Gabriel Voisin, as threshold braking on airplanes.
Are “zero-bag fares” really profitable for airlines? Any extra weight costs the airline in fuel. So, if none of the passengers carry any extra luggage (be it checked in or cabin luggage), will it lead to lesser fuel for the airline, thus lesser expenses, which would justify the lower “zero-bag fares”. Or, do the airl...	However not having any checked-in luggage means less overhead in terms of baggage handling as it's a bag less to load and keep track of.
Jettison and Dump fuel - Do they have separate meanings? According to the definitions, is there any difference between Jettison and Dump fuel? Does one of them use a different procedure, or they are simply synonyms? <Q> In the linked image, the large tank below the main body is an external fuel pod that can be jettis...	In the context of fuel, jettisoning fuel would imply that the fuel is in a container that can be detached while in flight.
Does landing in extreme weather conditions require any different or special training? Is there any special training, relating to land under extreme weather, such as snow storms, contaminated runways or ice conditions? <Q> On one hand there are physical limits to which a plane can be landed when it comes to wind both he...	Snow and wet runways in general may see a longer landing distance and roll out however this is not "special" training as landing distance should always be calculated based on conditions. In some regards there is but this depends on what you consider extreme weather . Every pilot must go through training for such situat...
Why should a test flight be performed when the propellers are changed? From this question I've learned that after a propeller change the plane should go through a test flight. Why is this? <Q> The purpose of the test flight is for the safety of passengers. <S> For most maintenance, in a not-for-hire aircraft, a priva...	It is so that the props are tested to see if they have any defects or not as well as to make adjustments based on their behaviour.
Do airlines employ FAs from their destination countries? I'm watching a documentary about daily business of an airport. There was a crew briefing for a Lufthansa flight from Germany to India, and as there was an Indian FA, the briefing was held in English (i.e. he didn't speak German). While it is advantageous to hav...	Generally speaking, crew are hired and certificated in the country where the carrier is based out of (and, incidentally, certificated to perform air transportation operations for hire), and would have to follow local employment and, potentially, immigration legislation should they wish to hire foreign nationals; certai...
Is there any cockpit procedure used to avoid shutting the good engine, instead of the bad one (on fire, for example)? Reading some reports, about the failure of crew members to fully understand the fault on engines, rarely, but it happens, the crew can misjudge the engine on fire, shutting down the good one. On airline...	If you look in places like Airliners.net the upper panel in an Airbus, you will find that the extinguishers have a cover to prevent the unintentional activation. Don't hurry in the engine shutdown.
What does the term "tanker" mean when used in regards to a passenger airliner? In a comment on this answer : Airlines will tanker fuel if it's substantially cheaper at another airport I've wondered what that term meant before, and now this comment leads me to think that airliners will carry more fuel than what's r...	Tankering means also more CO 2 Tankering means burning more fuel than strictly required, this can provide an economical advantage, but this operation is usually not neutral for our environment, depending on how fuel is delivered to airports.
Do helicopters try to take off and land into the wind? When helicopters take off and land is it preferable to point the nose into the wind? Since a helicopter is providing its own lift does it matter which direction wind is coming from? <Q> Moving forward through the air helps to make the helicopter more efficient, and...	Wind direction and velocity also affect hovering, takeoff, andclimb performance.
Is there a preferred turn direction for helicopters? If I have a requirement to fly a helicopter in a circle or racetrack over a point of interest that's stationary or moving relatively slowly, is there any reason to prefer left or right turns? I'm not concerned about visibility and I'm not asking about turns in a lan...	Vision is a valid reason, but only In confined areas [think valley or other aircraft]
How is passenger baggage transferred, and how does it happen so quickly? I've always wondered how airlines transfer bags between connecting flights. At a hub, bags must be moved to any number of connecting flights throughout the airport - some with very short connecting times. Seems like sorting them would take a lot o...	In airport baggage is handled from the check-in desk to the Unit Load Device (ULD) via a Baggage Handling System .
What do pilots actually see through the windows? As I have never flown inside a cockpit, but only played with simulators I find that the dashboard takes most of the field of view(or am I wrong?). So what actually can pilots see given good weather conditions, especially during critical parts of a flight, like take-offs...	In general, the pilots are required to have good visibility to execute any maneuvers during normal operation of the aircraft.
What lifting gas was used for barrage balloons during the world wars? During the world wars, various barrage balloons were used to protect targets from low-flying aircraft or similar threats (e.g. V-1 flying bombs), in particular by Britain. What lifting gas was used for such barrage balloons – the highly flammable hyd...	According to a BBC article here , hydrogen was used, not helium. I understand that the US protected their supplies of the much safer Helium.
Why does a hydraulic system failure increase the landing distance? Considering wide body aircraft, why do emergencies, related to hydraulic system failure, increase the landing distance? <Q> Any hydraulic failure will affect the landing distance as most of aircraft controls are operated by hydraulics. <S> Hydraulics...	If the high lift devices (flaps) become inoperative (or become degraded) due to hydraulic failure, the aircraft will have a higher approach speed, which will increase the landing distance.
How heading bug is calculated during cross wind and tail wind? From this question , it is been suggested to ask different question, rather than keep discussing it under comment section. How is the heading bug calculated and used for navigation when there is a cross wind? … when there is a tail wind? Will the headi...	So to answer your questions: You will use simple math or tools to compute the heading which will let you fly the desired track.
Is there a standard for the trip paperwork packages that are used by the airlines? I have noticed that different airlines (like LIDO, Delta, AA, etc.) have different formats for their trip paperwork packages, containing pre-flight information that they give to their pilots. These packages contain things like their fli...	The FAA prefers users to file ICAO format flight plans for all flights.
Could a fighter aircraft be operated indefinitely? Is it possible for an air force to operate a fighter aircraft indefinitely? Suppose a country has some Mig-21s or Mirage-IIIs. Is it possible for them to operate those aircraft indefinitely by continuously overhauling and upgrading them? <Q> Yes and no. <S> In Cambrid...	It's demonstrably possible to keep operating a military aircraft for at least a century after it's built.
Is there a tool to plot locations within X nm of a position? I'm looking for a tool to allow me to see what is within X nms or X hrs of my base airport. Is there such a thing? I remember a small airport I flew to once had a large map with a string attached to a pin located at the airports location on the map. There w...	At least a couple of tools exist to search for airports beyond a certain distance from your departure point.
How do airlines provide crews for the return leg of a long-haul flight? In a video , a Swiss International Air Lines crew flies an Airbus A340-313 (flight LX38) from Zurich to San Francisco. Then, they can be seen ( I am not sure if this is on the very same day ) visiting downtown and the Golden Gate prior to getting ...	Most of the airlines rent hotel nearby the airport of long-haul destination for the cabin crew and pilot.
Do any aircraft out there use negative lift? I think negative lift is where high pressure forms on the top of the wing instead of the bottom. I know that Indy cars use negative lift and some sports cars do, but do any aircraft exist that use negative lift and why do they use negative lift? <Q> A lot of aircraft generat...	Yes . . . . . . . . .
How can a military combat pilot indicate surrender? If a military pilot is captured by an enemy, how can he indicate that he has run out of ammunition to engage in combat or is not in a position to retaliate? Does he use lights, radio, and/or flares? <Q> There is no universally accepted means of surrendering an aircraf...	Assuming you didn't engage in combat, consider learning the other side's language and make sure you surrender in a top of the line aircraft.
Is an aircraft's maximum landing weight really weight, or is it mass? I'm calculating the lift of a Cessna 172 and I don't understand the numbers given for weight. The maximum landing weight is 2550 pounds which is nearly 1134kg. But does that mean 1134 Newtons (weight) or 1134 kilograms (mass)? Since weight = mass x...	The maximum landing weight given here is actually the mass , not weight.
Why are Airbus captain control sticks placed on the left when most people are right-handed? Why is it that control sticks for the captains on Airbus are placed on the left? Wouldn't it be uncomfortable considering that most of the people, and by consequence pilots, are right handed? To my opinion this would make flyin...	The key factor is that the throttle is almost always the middle - meaning that as pilots get used to sitting in the left seat early on in their training, they become accustomed to using the throttle with their right hand and the control column in the left.
What prevents a government from selling/leasing publicly owned airports? When an airport is open to the public, it is generally owned and operated by a government entity. If the local government leases or sells the airport, this would generate significant amounts of revenue. What are the legal impediments which disc...	In some cases the laws may not prevent the rental to a private organization but may require that the airport remain in public use.
Means of protection against hunter-killer UAVs I would like to know all existing technological means of defending an area against the MQ-9 Reaper or other hunter-killer unmanned aerial vehicles (UAVs) used by the United States in countries like Afghanistan, Syria, etc. Such means should either force the UAVs to leave...	The Cheapest Way To Bring Down A Hunter-Killer UAV Go to the ground control station .
Why is Hydrazine used to power the F-16's EPU? Why does the military use hydrazine to power the F-16's Emergency Power Unit (EPU)? What is so unique about Hydrazine fuel that it's needed to power the EPU? Why not use a less volatile and less hazardous fuel? <Q> This energy is freed by letting the hydrazine stream over...	To fill the voids in aeroalias' answer: Hydrazine is a monopropellant , something which does not need to be mixed and burned to free up the energy contained in its chemical bonds.
Do unused parachutes need to be repacked? If so how often and why? I was reading some military fiction and saw a comment that army airborne operations were required to repack all parachutes every ninety days, allowing parachutes that were due to be repacked soon to be cheaply used for training. This got me thinking: do...	I normally repack my main canopy before jumping, if it has been more than 3 months in my container.
Was there any progress in ramjet-powered helicopters after 1960? It seems in 1950's some countries investigated production of helicopters powered by ramjet engines on rotor tips - examples include American Hiller YH-32 Hornet or Polish JK-1 Trzmiel . The enthusiasm was short-lived - high fuel requirements, a signifi...	The simplest reason is just because there's no need for them - they offer no real advantages over a conventional internal combustion or jet engine, so as with so much else in aviation we stick with the tried and tested
What is the significance of Slip-Skid Indicator in PFD? Slip Skid Indicator as depicted in the picture below; What's the significance of Slip Skid Indicator? How Slip Skid Indicator is used in flying the aircraft? What are other performance/operations needs to be taken care while this exceeds its normal bound? Pri...	The slip/skid indicator is the small bar under the roll pointer.
Does tailless means no tail at all? When I was reading about the HAL Tejas I observed that it was described as a "tailless" plane. However I could see a tail in the picture . After careful reading I am assuming that being tailless means not having any tail planes a.k.a horizontal stabilizers. Does tailless means n...	Tailless usually means no horizontal stabilizer (tailplane).
Are there any manoeuvres that would be considered unrecoverable in a General Aviation / Training Aircraft? I'll try to make this question a little more manageable by applying the following constraints, though of course all answers would be welcome: By "General Aviation / Training" aircraft, I'm talking primarily abou...	Technically you may be able to recover from a spin with enough altitude and depending on the situation but a pilot could get them selves into a nasty situation by spinning either plane.
On the F15-E, can the WSO take over if the pilot is incapacitated? The F15-E Strike Eagle features a two-man cockpit. The pilot in the front seat and the WSO (Weapons System Officer) in the back seat. If the jet is cruising straight and level is mechanically sound but the pilot becomes completely incapacitated (from a...	They can fly the aircraft if required.
Can someone/something other than the pilot trigger the ejection seat? Let's say there was a two-person jet (take the F-15 for example) that was involved in some sort of accident in the air that incapacitated the pilot (unconscious but still alive) and left the aircraft unflyable. Could the copilot eject his fellow pilo...	So yes, something other than the pilot/s of the aircraft CAN potentially trigger the ejection seat. As to whether there can be automated systems that do it, the answer to that is a resounding "yes" as well.
Which came to be first - bigger airplanes, or longer runways? I'm generally speaking about airports with runways long enough for airliners, be historic or still in use. In order not to turn this question to a chicken-egg discussion, here are my points: Would making an airport(s) before making the actual airplanes bef...	In the end, airports have to weigh the benefits of letting heavier aircraft operate against the resources required for runway lengthening.
Why is carburetor heat use discouraged on the ground? I've been reading my private pilot books for when I start in February and Carb Heat has me stuck in a rut. I feel like I need to have a very solid understanding of this being that I live in a very humid area. The book says do not use carb heat on the ground and on t...	If you have carb ice, applying carb heat will cause your engine to make even less power (hot air is less dense than cold air).
Can a helicopter operate continuously in a small, enclosed, sealed environment? Many years ago I had an interesting discussion with a friend (while drinking). We were discussing what would happen if a helicopter was placed into a sphere of some size (slightly larger than the helicopter, a few times larger than the heli...	If you have flown an indoor model helicopter, you probably know that it is not advisable to come too close to the ceiling: The helicopter will become unstable and will be sucked right into it.
Is this the shortest route served by an Airbus A320? Is this the shortest route served by an Airbus A320? Port Louis to Saint-Denis, 231 km (144 mi). Air Mauritius flight MK248. <Q> This site seems to indicate that they had the shortest route using the A-320 family of aircraft at just over 70km. <S> The page also show...	The shortest route with an A319, which is an A320 family aircraft that I am aware of is Dar es Salaam - Zanzibar (HTDA, HTZA) which if I recall is roughly 73 kilometers (probably even less from airport to airport) operated by FastJet Tanzania.
What is the true meaning of the word “wilco” when used on the radio? What is its origin? Pilots often learn to use the word "wilco" on the radio through contextual interpretation. During my experience as a pilot communicating on the radio I have often observed pilots using the word "wilco" improperly. What is the true ...	"Wilco" is short for the phrase "will comply," meaning that the speaker will follow the instructions to which they are replying
What happens if an aircraft declares an emergency while there is another aircraft ahead cleared to land? Lets assume this situation: In a controlled airport, two aircraft are approaching for landing. #1 is about to touch the runway (let's assume it is within 1~2 miles from touch zone). Then #2 declares a emergency. I...	If they are both about the same distance (actually, time) away, then the emergency aircraft has priority (assuming that he doesn't decide to hold in order to troubleshoot, burn down fuel, prepare for the landing, etc), but essentially closing the airport from the time that the emergency has been declared until the emer...
Why is radar required on some FAA instrument approaches? The ILS / LOC approach at KCXY states radar is required. I understand I can't fly the approach if not in radar contact. However, if flying the LOC approach I think I can identify both final and HORVI (for lower minimums) using HAR VOR. There's no reason I'd need ...	Radar is required because there are no "published non-radar transitions" for this approach.
Why do the RNAV (GPS) approaches to KAPC not use the same missed approach procedure as the ILS/LOC approach? While looking at the various instrument approaches for Napa Valley (KAPC), I noticed a discrepancy between the RNAV (GPS) Y/Z RWY36L missed approaches and the ILS/LOC RWY36L approach: Why is it that the ILS ...	As best I can understand from the TERPS , it's because there are certain criteria for RNAV missed approaches that wouldn't be met by copying the ILS missed approach. For either ATC or convenience reasons they probably prefer you to go missed to the north east, hence they have the RNAV go that way.
How does an airport catch up when it is behind on traffic? When airports fall behind traffic for some reason and delays piling up, how do they catch up? If flights need to be cancelled, who decides (and when) - ATC, airport management, or airlines themselves? As an illustration, here is a snapshot from this page (ta...	They can recover by delaying everyone a little for a few hours, with the delay slowly reducing as the airport gets quieter With a very busy airport (Heathrow is often quoted as an example), however, it's possible that the airport is at/near 100% capacity for long periods.
Would an airliner be allowed to take off in snow? Im going to fly to Tucson tommorow. The weather is telling me its going to snow in Denver. So would snow cause a delay or are airliners allowed to take off in this kind of weather? <Q> Don't worry about it <S> While snow can sometimes cause a delay, airports are reall...	Departure rates will be limited by runway condition (the airports ability to keep them treated and clean), the throughput of the de-ice facilities and to some degree the aircraft arrival rate (you don't have planes to fly out unless planes are making it in).
How else can snowy/icy conditions disrupt airport operations? In casey's fabulous answer here , he identifies several ways snow/ice can disrupt airport operations: Continuous heavy snowfall can eventually close an airport if it becomes impossible to keep the runways clean, taxi routes become unusable due to drifti...	Snow (and ice) in runway can affect takeoff by absorbing energy and can impact the aircraft after being kicked up by tires.
What are the ways to burn fuel faster in case of emergency without fuel dumping system? In many cases, the maximum landing weight of an aircraft is lower than the takeoff weight due to the amount of fuel it carries. While some aircraft have fuel dumping systems, others like the A320 family and Boeing 737 do not, and s...	For increasing fuel burn, the pilot can simply increase drag by increasing the speed. My recommendation is to stay low and fly in approach configuration (gear, flaps and slats out) as close to 250 KIAS as the configuration allows.
How do rocket engines produce more thrust than aircraft jet engines? I can't find the reason why rockets are able to produce so much thrust when compared to turbojets. I do know that the rockets carry their own own supply of oxygen since there is no oxygen in space or the upper region of our atmosphere. And that the u...	It is simply that the rocket operates at much higher temperatures than gas turbines do.
What is the aerodynamic effect of a panorama (skydeck) near the tail section of a commercial airline? A company called Windspeed Technologies posted the following concept video of a panorama seating option aboard a commercial plane. From the limited understanding I have of the phenomena called flow separation , su...	The end result here is that the effect is probably minimal for several reasons: First, competent shaping of the protrusion should result in minimal disturbance to the airflow in that region.
What is the rationale behind very short distance flights? I was impressed to read here that some passenger airline routes are even below 60 km in length. Even assuming that the passengers are already in the airport past the security check, probably a good bus could depart from the same gate and arrive to the destin...	One other rational for unusually short overland flights is that the short hop is a layover to connect two small airports to a larger one.
Why don't planes use pulsejets? According to my research, a pulsejet's thrust grows as the airspeed increases. Most pulsejets require no moving parts which makes it easier to manufacture them. They are also very lightweight which can have some great effects on aircraft. They are very slow at zero airspeed but very f...	Also, pulse jets tend to be very loud, which can be a noise problem.
Before a flight, what are the most important things to check in an aircraft (walkaround)? During the pre flight inspection, usually the copilot checks many parts of the aircraft. Which are the parts and Why do they check them? <Q> Many things are checked on a walkaround. <S> The pilot-in-command should do the walkaroun...	The main classes of items are as follows: structural integrity ; the aircraft must be sound and undamaged and ready to fly sensors ; sensors such as antennas and gauges should be undamaged and not have anything blocking them or adhering to them clean flight surfaces ; the control surfaces and flight surfaces must be sm...
Why are almost all STOL aircraft high-wing? Isn't ground effect a big factor in STOL operations? Don't low wings produce greater ground effect than high wings? Or is it a practical concern, that most real-world STOL operations are in unimproved or slightly-improved locations, and high wings are more likely to clear "...	High-wing designs are not as susceptible to the ground effect and therefore may have better landing performance (less float).
Why do we lean the mixture when the air become less dense? In a carbureted engine at higher altitudes, less dense air means there is less air entering the engine. Wouldn't we want the mixture to be full rich to allow the maximum air into the engine? I understand that the engine will become rough if we don't lean the e...	As the aircraft climbs into thinner and thinner air the mixture must be "leaned out", where the volume of fuel and the fuel molecules is reduced, to compensate for the fewer number of oxygen molecules being pulled into the engine.
Why does rudder cause roll? In the few rudder incidents with the B737, rudder-freeze caused the airplane to roll. From what I know, the rudder causes yaw while the aileron causes roll. Why in the case of these accidents/incidents would the rudder cause a roll? <Q> There are many higher-order effects. <S> For example,...	Wings that are swept backwards, as on the B737, contribute to the roll towards the direction of the turn, because the outer wing gets effectively longer ( visual explanation ) and produces more lift.
Why are some airplane wings not painted? Why is it that some wings are not painted on commercial jets? Couldn't they paint them the same color as the fuselage or would it be a waste of money? <Q> Fuselage present a large vertical surface with greater length than height. <S> Wings are a large horizontal surface that is ...	Many commercial planes actually do have paint on the wings, but the paint is white, or light grey. Protective paint is used in certain areas to prevent corrosion, and it is used on all composites to prevent erosion and moisture ingress.
Why do most commercial airplanes use hydraulics instead of electric/servo motors? I'm sure it's possible to use servo motors to get precise control of the ailerons, elevators or the rudder. But still, hydraulics are widely used instead. Hydraulics do have a disadvantage that a damage to the hydraulic pipes can cause ...	As aircraft move toward "More Electric" architectures, there may be a greater drive toward EMAs throughout to minimize the required plumbing, maintenance, and system weight of hydraulics or EHAs. They also are concerned that when the gear train wears out, it will have slack, which may lead to limit cycle oscillations.
Do I need to register my drone? Recently the FAA released some new regulations that require drone operators, including hobbyist, to register drones with the FAA. As I am a novice in both aviation and legalese, can someone please break down the regulations and give me a guideline in layman's terms for whether or not I ...	you need to register your drone through the FAA's online registration system .
Why shouldn't the pilot change the aircraft's configuration while avoiding windshear during landing? According to the procedures, when going around, due to windshear, pilots shouldn't change the aircraft's configuration, such as flaps position and landing gear extension. If changing, would the aircraft lose the lift? w...	If you suddenly retract the flaps while flying at final approach speed, you will lose a lot of lift and potentially even stall the aircraft.
What was the commercial speed of Concorde? I work on time-space cartography in a historical perspective and need to establish a commercial speed of Concorde aircraft flights based on timetable data. This issue differs from the issue of the maximum speed of planes , because in a time geography perspective I want to c...	The Concorde cruised at 1350mph (~Mach 2.05 at 55,000Ft.) 1 560 km/h was the commercial speed of Concorde (or 969 mph in non international units).
What makes a visual approach quicker than an ILS approach? In the question What's the preferred approach for a passenger jet? it is mentioned that pilots prefer Visual Approaches over ILS Approaches, as they are a lot quicker. Why would a visual approach be quicker than an ILS approach? <Q> Visual approaches can be ...	It's also worth noting that apart from flight time, another reason to prefer visual approaches is that a pilot (a private one, anyway) has a much lower workload.
Do airlines have to get permission from the FAA if they want to change their livery? Do airlines have to get permission from the FAA to change their livery? It would be great if someone can throw in some examples where this has happened. <Q> Not the FAA, but the manufacturer. <S> If the parts are composite, only a sm...	In general, the aircraft owners can paint the aircraft whichever the way they want.
What liability concerns would drive an airplane homebuilder to scrap their plane? Via this post by Ron Rapp , I found this video of a plane owner and builder dismantling a GA plane and then scrapping the airframe. The video claims this is because after consulting with aviation attorneys and other experts regarding...	If that plane crashes some day and especially if it is fatal, someone is going see it is a homebuilt experimental and sue the guy who put it together, alleging they did something wrong.
What are the physical/aerodynamic implications of designing a prop guard for multirotors? A number of drones these days like the one shown in the picture below have fully protected multi-rotor propeller guard system . These are lightweight, aerodynamic housing that keeps these spinning knife-blades away from people'...	In general, having a shroud (a duct actually) over the propeller reduces the tip losses; however, in an UAV, this effect is pretty small (and requires tight clearances) in order to have any practical effect.
How should Isopropyl Alcohol be used as an AvGas Fuel System Icing Inhibitor? I understand that 100% Isopropyl Alcohol (IPA) is used as a Fuel System Icing Inhibitor (FSII) additive in aviation gasoline systems—including 87 through 100LL fuel types—for cold weather operations. I know that IPA is, or can be, included as...	Although approved for use in Lycoming engines, do not use isopropyl alcohol in the aircraft fuel systems unless approved by the aircraft manufacturer.
What are good resources on causes of private aircraft crashes? I'm working on getting my PPL, and I would like to read more about the specific causes of small private aircraft (single or twin prop, primarily) crashing, especially those that were caused by pilot error. Are there any good books or other resources on this...	The AOPA's Air Safety Institute has quite a few resources that I like to review from time to time, including some great videos with commentary on exceptional cases.
What are the criteria that govern the choice between titanium, composites, and more common materials, like aluminum? In the newest large commercial jets, composite materials seem to be all the rage. The first thing I wanted to know is why composites were chosen instead of titanium? If I'm not mistaken, titanium has eve...	Composites are also easier to engineer for some specific purposes, such as having higher tensile strengths in critical directions.
Would a chain strip built in the airport taxiways, help airlines in saving money and time during taxi? I am referring to the mechanism used in aircraft carriers, which help in catapulting fighter aircraft. What I had in mind is a milder version of the same concept. It would massively save cost, due to it being operated...	A chain system would also be very expensive to install and run, probably more expensive than the fuel it takes to taxi the airplanes.
Has anyone considered putting a hydrofoil on a sea plane? One of the main problems with water landings is that you need a bigger engine to counter the various drags caused by the pontoons. The specific case of "run[ing] across our own wake to be able to get up on the step on glassy water" brings some interesting thou...	The Convair F2Y Sea Dart , a 1950s prototype jet-powered fighter, used two 'hydro-skis' for takeoff and landing.
Do any commercial airline models have a parachute at rear to help in landings? Some land-based fighter aircraft have a drogue-chute to help them slow down during landing. Do any current models of commercial aircraft have a similarmechanism? Secondly, would such a mechanism help aircraft in making a better landing an...	The need to use a drogue chute can limit the crosswind landing of the airliner significantly. With the improvement of the brakes and reverse thrust, parachutes are no longer an option for airlines.
What is the bypass air in a turbofan engine actually for? I'm planning on building a small model turbofan engine for a bit of fun but I thought I'd better get a better understanding of how they work first. I understand the majority of it at the moment but I'm struggling to see what the bypass air actually does, to my m...	The bypass air is actually what gives the jet engine most of its thrust.
Is it possible to tilt a propeller for attitude control, similarly to jet thrust vectoring? Are there examples of propellers tilted in a controlled way to help in attitude control for pitch and yaw, adding a torque component? Tilted propeller assumption This would be similar to thrust vectoring in jets. Vectored th...	There are also some aircraft like the V-22 Osprey which use some variation on this control method.
Which Aircraft Models need a Tripod Jack for tail support at airport? Which are the aircraft models that need their tail to be supported by a jack when empty? Wikipedia says this: Aircraft Tripod Jack They are used to support a parked aircraft to prevent their tail from drooping or even falling to the ground. W...	DC-8 freighters used tail supports as a safety precaution. Tripods are mostly found in cargo aircraft (and combis) as the cg shift is severe there (particularly for front loading). BUT for a 747 Combi I would say that a tail-stand is indispensable!
What are "Alternate Minimums"? As I asked question about weather minimums yesterday, I've read some material including TERPs. And In the FAA 8260.3b, 'Taking and Landing Minimims' 3.1 there is one sentence "alternate minimims, when specified, must be stated as ceiling and visibility." But I don't know What alternate...	Generally, the destination's weather has to be FORECASTED more than 2,000 ft. ceilings and 3 miles visibility, or if not, you have to IDENTIFY an alternate destination airport in your flight plan.
Why is the take off speed and distance reduced by head winds? A headwind of 20 knots and a true airspeed for the take-off safety speed being 120 knots, the ground speed is only 100 knots. Getting to a true ground speed of only 100 knots will require less distance. Anyone can explain to me is that mean that the distan...	Yes, the distance will be less in both cases because the amount of time needed to reach the take-off speed is reduced because the necessary groundspeed is reduced (minus the time needed for 20 more knots in your case).
Are aircraft capable of sustained inverted flight at constant altitude? Inverted flight as a part of manouveres, dogfights, acrobatics is fairly common but my question is: Are any aircraft capable of sustained inverted flight without losing altitude? e.g. Could you fly 10 mins inverted at the same flight level? To cl...	Military and high performance aircraft typically include some mechanisms for maintaining fuel flow during negative G maneuvers like inverted flight.
Is there a benefit to a pilot/aviator having an FCC GROL license? I am an avionics technician (c-130) in the USAF and plan on learning to fly helicopters when I separate in about a year. I have debated whether or not to pursue a GROL or possibly A&P . From what I know, these are generally intended for maintainers/...	An A&P could be very valuable to you as an aviator in general. The only FCC license that you might need is the restricted radiotelephone operator permit (RR) .
Why is horizontal stabilizer set to 4° up in airbus aircraft for take off? Why is horizontal stabilizer set to 4° up ( or any other setting other than neutral) in airbus aircraft for take off? Why can't we keep the trim neutral? <Q> On landing, aircraft are configured for a stabilized approach , which means that the a...	Both landing and take-off are critical phases of flight, and it is standard procedure to configure the aircraft for those phases to reduce the workload on the crew.
What is the difference between a positioning flight and a ferry flight? What's the difference (for the purpose) between positioning and ferry flight? <Q> This is often done when the aircraft finishes its day in one city, but is needed in a different city the following day because another plane has broken down. <...	A positioning flight is a flight for the sole purpose of positioning the aircraft to conduct another flight from another airport. There's no absolute accepted definition across the world, however generally it depends on whether passengers could be carried on the flight.
When can a pilot disobey ATC commands? The title really asks it all: When can a pilot disobey ATC commands? . Of course, the pilot has the final decision, but when would the pilot really disobey someone in ATC with much more knowledge of planes and other potential hazards near by? <Q> In case of emergencies, yes. <S>...	The pilot in command has the final authority and responsibility for safety of the flight and can disobey ATC commands in case of emergencies.
Why was the A380 built with a gull-wing design? I've noticed that the wings on the A380 are very curved in comparison to the 747. I mean the 747 has a lot of wing flex but the A380 has less wing flex and the wings are flexed down in comparison to the 747. Here there are two photos that might help you understand what I'...	This has some economic benefits, the main one being shorter landing gear while giving enough ground clearance for the engines.
How do aircraft go off-course even with all their guidance technology? Pilots today have more than enough technology both in the cockpit and in the infrastructure that supports them to know with great precision where they are at any given time. How/why do they still sometimes go off-course? <Q> 2) Humans are fallible. ...	On top of that there's simple crew distraction - if they're manually flying then they may be focussing on something else and not notice that are off-course: As happened on the Sukhoi superjet demonstration flight a few years ago. 1) Technology is fallible.
Do I have to declare an emergency if I cut into fuel reserves? In another question , I wrote You only need to plan for regulatory reserves. You don't actually have to land with them and @Jan replied: you have to declare emergency if you do cut into them though and that will quite probably get you an investigatio...	The pilot in command must declare a situation of emergency fuel when the calculated usable fuel predicted to be available upon landing at the nearest aerodrome where a safe landing can be made is less than the fixed fuel reserve for the flight.
Why do delta-wings perform so well on paper airplanes? Based on this question, it seems that delta-shaped wings do not perform well at low airspeeds. But why do paper airplanes, particularly the most well known one, fly well even though the airspeed they fly in is at most 15 knots on average? <Q> Your interpretation ...	Delta wings don't perform well at low speeds compared to other low speed wings such as straight ones.
Why is pitch measured with respect to the horizon and not the ground? Why is the pitch measured with respect to the horizon and not the ground? How different are the angles between the ground and the horizon? Would it be possible to fly with an attitude indicator that indicated pitch with respect to ground rather than ...	Pitch is determined with gravity, which always 'points' to the center of the earth. An airplane needs to be oriented to a frame of reference which does not change depending on altitude or the elevation of the ground, this is so the pilot will be able to judge the angle of the wing through the air flow.
What are the advantages of a Trimmable Horizontal Stabilizer? What are the advantages of a Trimmable Horizontal Stabilizer (THS)? For example, a THS is used on some Airbus and Embraer aircraft. What is the most important advantage, and why don't some other successful airliners have this type of horizontal stabilizer? ...	The THS offers some important advantages like: The required elevator deflection angles are smaller in case of trimmed aircraft and the system has full elevator deflection angles at extreme trim angles. It allows for a wider range of c.g. movement compared to the elevator-trim tab system. The large trim changes with cha...

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