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How do you determine the proper rate of descent for landing? I'm trying to use a simulator to learn to land properly. One part that I'm finding really tricky is picking a proper rate of descent. I know I'm supposed to do my best to keep it so I have two red lights and two white lights on the Precision Approach Path I...	It helps to know the pitch and power settings for your jet.
Does European airspace use the metric system? I figured this was probably a no brainer, since Europe uses the metric system, I assume the airspace does... But then I remembered that aviation likes international standards, and I know the US uses Imperial so, does Europe as well? And, yes or no, why do they take that...	European Civil Aviation Authorities use the imperial system to depict altitudes and airspace restrictions (feet), speeds (knots) and distances (nautical miles).
Can an outside observer tell if an aircraft is flying through turbulence? As a passenger, when I look out of the window, I can see the wings shaking. What would another plane (not in turbulence) see if they were observing the same plane (in turbulence)? <Q> The wings are more aerodynamic than the body of the aircraft. ...	The wings are flexing because there is a change in lift.
Why is vertical take-off restricted to lighter weight aircraft? Vertical take off is a big advantage, but why it is only limited to low weight? For example, fixed wing like An225 can lift more than hundred tonnes of payload, while the biggest helicopter is 25 tonnes. Why there is no effort to build a helicopter can li...	As long as you can make the wing bigger without it breaking, and as long as you can add enough power to overcome the extra drag, there aren't many fixed limits With a helicopter, we're limited by the rotor tips: once they go supersonic, they cause a lot of problems.
What advantages are provided by an unstable canard configuration for fighters? Why are most canard fighter aircraft unstable? A stable design would let the canard provide lift. My guesses are: Increase pitch rate Decrease stability while supersonic (supersonic, the aircraft are stable) <Q> This confirms your first...	You want your control surface to create only little lift, so it has enough margin for maneuvering.
Could fly-by-wire protect against a takeoff tail strike? If the takeoff weight is underestimated, rotation will be done too early and may result in a case of tail strike. One example of such mistake is a 747-400 (F-HLOV) in 2006 (case 8 in this study ). The crew entered ZFW for TOW (100 tons lower), VR was underestim...	On Airbus aircraft, the guidance law provides attitude protection on take-off which should prevent a tail strike.
Are there non-economic barriers to a 1000 passenger aircraft? I know the number 1000 is just an arbitrary number that happens to have some zeros in it, but is there any non-economic obstacle to making a 1000 passenger aircraft? Also, assume normal-ish space-per-passenger constraints, so 1087 people on a 747 isn't re...	Scaling laws tell us that the structural mass fraction of such a big airplane would increase, reducing its efficiency.
How many passengers can an Airbus A380 carry? What is the passenger capacity of an A380, and how many suitcases could it carry? <Q> Wikipedia lists three basic configurations for the A380-800: 407-526 <S> (3-class) <S> 644 <S> (2-class) 853 <S> (1-class) <S> However, different airlines have different configur...	Luggage isn't a limiting factor for the A380, as it can hold approximately one suitcase per passenger in the luggage hold, and a further 2-4 suitcases per passenger in the bulk hold (depending on whether other cargo is being carried) In practice, it's usually configured for 525 in a typical "three class" (First, Busine...
Can I become a pilot if I am under treatment for Attention Deficit Disorder? I know that before you even begin training in flight school, you are required to get a physical examination from a doctor to determine if you are fit to fly. Online articles stressed the importance of being completely honest with the doctor ab...	ADD is not a disqualifying condition, however if you have a formal diagnosis of ADD or ADHD My recommendation is to not say anything.
What aircraft can make these sharp 90-degree turns? I took this photo when I saw a plane make a crazy 90 degree turn. What kind of aircraft could do this? I have a plane finder app for commercial aircraft and this plane did not show, which is the first time that's happened. <Q> It looks like a 90 degree turn, but it is...	As we do not know which airplane were you observing and neither the airspace it was moving in, one possibility, aside for military aircrafts, it could be that it was an acrobatic one, maybe training on specific maneuvers.
What are the spiral marks in the center of the engines? When I get a chance to peek inside an engine, I noticed that many have spiral marks painted in the center. What is the purpose of these? Pictures: <Q> The benefit of these white markings inside the engine is twofold: <S> The ground crew can tell if the engine ...	Our aerospace engines have swirls painted onto their spinners in order to indicate when the engine is rotating while on the ground. As a long time ramp agent for Delta and Southwest Airlines, I can tell you they are a critically necessary element to ground crew safety.
Can a passenger request to visit the cockpit during a flight? As a kid, I remember going to the cockpit of a plane with my mom (I believe the airline was AOM French Airlines ). Is this still possible now? I understand the answer might differ with different airlines/countries, I'm mostly interested in European and As...	Usually the cockpit is restricted during any phase of flight besides boarding/de boarding.
Why must the throttle be moved slowly? User 'Calphool' writes : For example, in a real plane, if you jam the throttle forward too quickly, you can kill the engine or make it backfire. This may sound like a trivial detail, but people have died on takeoff because they never learned proper throttle technique. Why an...	Quick changes require bigger changes, slower changes give a pilot more time and allows smoother transitions.
Can commercial aircraft dump luggage or cargo mid-air? In a situation where the pilot realizes that weight of the aircraft is too high, can they dump luggage / cargo mid air, similar to dumping fuel? <Q> No they can't. <S> The cargo doors are secured and will not open mid-flight. <S> Cargo holds are usually pressuri...	In the early days of commercial aviation, dumping luggage due to low fuel was not unknown.
What type is this aircraft, appearing in the movie "Kingsman"? In a scene of the movie Kingsman: The Secret Service the young aspiring agents have to skydive from an airplane. I didn't recognise it: which airplane is it (assuming it actually exists)? I could only find a picture from inside and one from below . <Q...	That distinctly squarish shape looks like a Short SC-7 Skyvan 3-100 , especially since the registration on the photo from below is visible: G-BEOL . Indeed, this is a Skyvan.
What is the minimum distance allowed between two parallel runways? Is there an international regulation for this matter or does it differ from one country to another? <Q> In the United States, the FAA has published Advisory Circular 150/5300-13A, <S> Airport Design , which includes standards and recommendations for a...	"For simultaneous landings and takeoffs using VFR, the minimumseparation between centerlines of parallel runways is 700 feet (213m)."
Can VOR indication be reliable if one of its antennas breaks? What will be the reliability of the VOR indication inside the cockpit if one of the two outside antenna is broken ? Can we trust it to make a VOR approach? What will be the consequences assuming that we are in a general aviation aircraft like cessna 150...	The only effect of a broken VOR antenna is that the polar pattern of the antenna will be altered, and its efficiency as an antenna decreased because it will be mismatched to the feed line.
Do aircraft have siren to warn public in case of a crash over land? The recent crash of a Taiwan aircraft, got me thinking, do aircraft have built in siren, which can warn people on the ground of a possible crash to give them some headway. If that is not practicable or feasible, then what solutions are feasible, or on...	People on the ground would have very little time to hear a siren from an aircraft approaching at a hundred miles per hour or more.
What does it mean for a door to be armed? What does "arming a door" mean? Is the orange tape that's applied over a window related, perhaps as an indicator to people outside that the door is armed? <Q> Prior to departure (usually before engine startup), all the aircraft doors are placed into the armed (or automatic) mo...	If a door is put into armed mode , it will trigger the evacuation slide when the door is opened.
Do emergency services helicopters fly VFR when leaving base? I've recently been watching an interesting documentary on helicopter paramedic teams. As you all probably know, their job consists of a lot of sitting around doing nothing before a scramble and then a short (or not-so-short) flight out to the middle of nowher...	Each operator and pilot have different policies, but in general police helicopters will rarely if ever fly IFR, and medivacs will only fly IFR if they judge it safe.
Why do jet engines use kerosene rather than gasoline? Could you run a jet with gasoline? Why do all jet engines use kerosene? <Q> You can persuade a turbine engine to run on just about anything that can burn. <S> So the decision of which fuel to actually use depends on the side factors including, but not limited to: ...	Gasoline is too volatile for a jet engine; Diesel fuel is not volatile ENOUGH for a jet. To my knowledge, all "Jet fuels" (intended for aircraft use) are based on kerosene.
Do planes return to service after non-fiery crashes? A Turkish Airlines flight recently ran off the runway and ended up on its belly in a field. The landing gear were damaged, but the plane didn't burn and the fuselage remained intact. Are planes involved in this sort of accident repaired and returned to service, or...	If a structural member is bent or crushed, then usually a small plane will be unsalvageable, but if structural members are intact and undamaged, then usually the aircraft can be repaired.
How can an airplane land if a hail storm damages the windshield? I understand hail can be very damaging to an aircraft, in particular to the engines and windshield. In the event that a windshield becomes cracked so that visibility is impossible, can pilots pop out the windows when at a lower enough altitude in order t...	Some airplanes, like the Pilatus PC-12 pictured below, have a captain's side window that can be opened during landing so that the pilot has a direct view of the runway.
Will ATC proactively route traffic around bad weather? When thunderstorms or other severe weather crop up, will the Air Traffic Control in the area proactively route traffic (horizontally or vertically) around the trouble area, or do they leave it up to the individual pilots to request an alternate route? My intent wa...	They will at least advise the pilots of the bad weather that they can see, and can offer the pilots a deviation or let them know what previous flights have done.
Why are aircraft external lights round, not tear-drop shaped? I saw this image of a Cessna 172's tail posted on another question and it made me wonder why the beacon light is basically a cylinder, and not a more aerodynamic, teardrop shape? Image source <Q> That beacon lens (and most of the strobe lenses shaped like ...	The answer is overall airplane optimization.
What is the difference between "flight level" and "altitude"? I have seen references to "FL180" and "FL300", and I know that they stand for Flight Level 180 and Flight Level 300. I've also seen references to "an altitude of 18000ft" or "an altitude of 30000ft". What is the difference between flight level and altitu...	To understand a flight level, we should understand how altitude is measured in an altimeter, which is essentially a calibrated barometer - it measures air pressure, which decreases with increasing altitude.
What are the pros and cons of a pulsejet? I've heard pulsejet powered aircraft can fly at very fast speeds but are there any drawbacks to this type of engine? And are the disadvantages greater than the advantages or vice versa? <Q> Consequently, it needs speed to work well. <S> If the pulse jet is on the ground, it is ...	The pulse jet engine works because it uses the dynamic pressure of air for compression. Very easy to build, very light. They are very very noisy.
Why is there a compressor in an air cycle machine? I'm a curious high school student. Why is there a compressor after the first heat exchanger in an air cycle machine ? I've read that compressing the cold air is for the cause of efficiency because compressing hot air uses much more work than cold air, and the effect o...	It keeps the volume of air low and allows for smaller, more efficient turbochargers.
How quickly could a commercial airline integrate advances in technology into its fleet? How quickly would a commercial airline be able to integrate significant advances in technology into its fleet? Specifically I am interested in large commercial airlines and advances in technology that would substantially increase t...	Immediately in some cases.
Is it required to memorize checklists for better efficiency? Military pilots are instructed throughout training that they must learn all checklists off-by-heart (in the RAF anyway). This way things get done much quicker, primarily in the event of an emergency when the immediate actions must be performed like 2nd nature...	The upside of memorized checklists is that you can execute the checks much more quickly; the downside is that many of the detailed troubleshooting checklists used for non-normal conditions that arise in commercial aviation are much longer than a pilot can reasonably memorize. In the US the closest thing to a standard, ...
Did commercial airliners have microwave ovens in the past? So I went on 2 long (total of 16 hours) flights with a major US airline, and they did not provide a free in-flight lunch (grr) during either flight. I had brought a sandwich with me just in case, but when I asked the flight attendant if they could heat it up th...	Some flight attendants mention that they can warm your food, but some say that they will not for legal and health reason. We had microwave ovens on all of our 747's. I could not find any reference where commercial airplanes used to have microwaves.
How often do people fly SVFR? I was going over Special Visual Flight Rules (SVFR) with my instructor recently and he told me that he has only requested it a few times, and that it is mainly used if you are flying from deteriorating weather into improving weather. In other words, you are sure that where you are going ...	The facilities I've worked, it's been usually a tool, when people are trying to get in right before the weather hits, or they're seeing good improvement in neighboring airports and at the main one, and know that it'll be good enough to make it between the two areas. Copters fly SVFR more often than fixed-wing for a num...
Why would a helicopter climb in a spiral? I was just watching the James May's Toy Stories Christmas Special Flight Club * , and in it he commented that the helicopter was making a spiral climb to 8,000'. Why would the pilot spiral, not just essentially go straight up? * An excellent series if you're a big kid who ...	In the spiral, the helicopter generates translational lift , which is added to the lift generated by the downwash of the rotor system, improving its ability to climb.
Is ATIS information - including identifier - available on the internet? According to Section 2-9-1-a of the FAA's Air Traffic Organization Policy, a phonetic letter is assigned to each tower-issued ATIS update. This information is available on the ATIS VHF frequency for an airport, or via a phone call to a designate...	The ATIS is only a VHF recording, but even when recorded digitally, it is not available in a text-base form in many cases which would allow being made public on the internet.
Why aren't there more passenger helicopters? I've observed helicopters being used often in the military for medical flights for other special use purposes, such as sightseeing and news reporting Why aren't there any commercial passenger transport helicopter flights? Or are there any examples of this? Are airplane...	Several factors contribute to this: Frequent traffic issues leading to unpredictable delays in major roads; Presence of an elite having enough money to afford such flights; Availability of a sufficient number of helipads. Spending years being ferried off and on shore by helicopters, I'd say the biggest problem is noise...
Can a software "hard freeze" or serious hardware problem completely disable the whole cockpit? I think that the glass cockpit of a modern plane has some sort of a central power supply or at least some central controlling software. What happens if this central power suddenly disappears, or the central software freezes?...	So yes, things can fail, causing cockpit displays to go blank and other problems. While total electrical failure in a transport-category aircraft is extremely remote, even fly-by-wire airliners such as the A320-380 and B777/787 have redundant backups that would work under the scenario: in the case of the Airbus, you'd ...
Are two people required in cockpit at all times on large commercial aircraft? It would seem reasonable on large commercial airlines to require that there be two people in the cockpit at all times. For example when the pilot goes to the toilet a member of the cabin crew must enter the cockpit until the pilot's return. S...	The "Two Crewmember Rule" has been mandatory for all US passenger airlines since 9/11 as well as for all foreign airline flights in and out of the US.The
What vertical flight profile could be expected from an aircraft if the pilots were incapacitated? If there were nobody at the controls what kind of vertical profile could be expected from, for example, a modern airliner? After reaching the cruise altitude I assume the pilot just sets a nav route and altitude on the o...	a properly trimmed aircraft with no pilot input could be expected to roughly maintain altitude and once out of fuel it will descend at whatever rate is required to maintain its trimmed airspeed.
How can the breath of a pilot be recorded? On a plane, as a passanger, I can't hear my own breath. I can't hear my own breath even in a silent room. On a plane, there is a continous background noise. And the microphone recording the noises in the cockpit, are probably not directly at the lungs of both pilots. I am r...	However, if a pilot is breathing abnormally, the cockpit voice recorder may easily detect that as the breathing sound is captured by the CVR.
What can airline pilots do if they are no longer in the position to fly, career-wise? I was having a discussion with a friend about the incident in the past days (4U 9525) and more specifically the what could be described as 'Taboo' of Psychological problems among pilots. We came across a few points: They will only r...	I mightily preferred to work with other pilots - they would have a much better grasp of "what looks about right" and not pursue hare-brained, outlandish ideas.
Is head-on or trailing wind better? Does a powered aircraft fly faster when in a head wind or with a trailing wind? The question revolves around the head wind should provide 'better' lift, and trailing winds have very little to 'push' against. <Q> A tailwind provides a faster groundspeed. <S> The aircraft moves throu...	If you are having tailwind, the aircraft will travel with the same speed through the air, but with an increased speed over the ground.
Is there a legal requirement to tell your doctor you are a pilot? Specifically if I visit a doctor in Canada who is not a CAME for my regular aviation medical, do I have to tell him/her that I have a pilot's licence? You can imagine why I'm asking. I just explained to someone that I'm supposed to mention this to any ...	In the US, you are not required to inform a doctor that you are a pilot.
What kind of sunglasses are good for flying? I'm a beginner at aviation. I'm currently in training for gliders license.Our instructors mentioned that sunglasses are very important if not mandatory. What kind of properties do I need to look for in sunglasses to determine whether they are good for flying? <Q> No polari...	Good eye coverage is key and this will depends on your eyes and how different glasses sit on your face.
How are GA aircraft ferried from factories? It's relatively easy to transport jet aircraft like Airbus and Boeing: most of them have a long range, and a few hops at most would get them to the owner. But how would a Cessna manufactured in U.S. be delivered to Dubai? It would not have the range to cross the Atlantic. Ta...	As you've guessed, there are two options: a ferry flight, or shipping the aircraft in a container.
Does Daylight Saving Time affect local airspace? Only some countries use Daylight Saving Time. In Canada, some provinces use and don't use DST (such as Saskatchewan). However, in remote and local regions where this is not observed, what would happen? What happens when areas that do not observe DST are controlled by ar...	Aviation always uses UTC time .
What would prevent a solar powered aircraft staying aloft forever? Focusing on aircraft, not balloons, I found this question that led me to some basic research on atmospheric satellites . I imagine the technology has evolved since NASA's research more than 10 years ago. Given the following points: The aircraft ...	In addition, their design requires a very carefully managed flight envelope: an unstable air mass could easily destroy the aircraft. I'm not sure which would be the limiting factor, but I think that either some equipment wouldn't be operational without maintenance, or you would get a mechanical failure of some kind.
Are military jets always scrambled when communication to a commercial aircraft is lost? I've heard that in case a commercial flight does not respond to Air Traffic Control, military jets would always be scrambled to check the state of the flight. The benefits of scrambling jets are clear. My question is, are they al...	Over Europe and many other parts of the world, the general rule is that if an aircraft in controlled airspace does not reply to instructions from Air Traffic Control, military jets will be scrambled to intercept the aircraft. Back to the question, NO .
Why does manifold pressure increase with power? Whilst writing an answer to this question , I remembered something I don't really understand. The partial vacuum in the inlet manifold is caused by the piston descending with the inlet valve open during the "suck" phase of the Otto cycle. It is this vacuum that causes ...	The amount the throttle is open determines the pressure in the manifold.
How does a CVR / FDR determine when to stop recording? For example, the CVR records only about 2 hours of data. Overwriting important data must be avoided, and thus the recorders should know if a catastrophe has happened. Then they can stop recording (to protect the already recorded data from overwriting), and start s...	In more serious crashes, the boxes stop recording because of the physical destruction of everything but the memory units (only the memory units are built to survive crashes).
How much does it cost to give an airliner a fresh coat of paint? Just a random thought I had: the weather gives a jet's paint job a battering; meaning they need to be resprayed approximately once every 5-10 years. (See How often is a passenger jet aircraft painted? ) Roughly what might a paint job for a 777 like the...	According to WallStreetJournal article , Tom Horton stated in an interview that : A 777 paint job can cost \$100,000 to \$200,000, depending on the number of colors involved, and a smaller Airbus A320 can cost $50,000 or more.
Is "General Aviation" a well-defined term in the US, in the EU and/or elsewhere? In this earlier question I tentatively assume that GA means civil aircraft operations other than scheduled passenger transport - what I think of as "airliner" operation though it could include quite small aircraft operating a scheduled f...	In common parlance, "General Aviation" typically means "not-airline".
Is there a maximum lift to drag ratio? If I recall correctly, the best competition gliders have a L/D ratio as high as 60:1. What imposes this limit? Is there a maximum theoretical L/D ratio, or could sufficiently advanced materials allow a glider with a L/D ratio of, say, 200:1? <Q> Gliders need to fly in tight circle...	With current technology the L/D might go up to 70 or 75, and going higher would require an almost impractically large wing span.
Why don't fighter jets take off vertically? I've heard the claim repeated many times that some modern fighter jets have an installed thrust greater than their weight, so theoretically they could accelerate straight up. I've never actually heard of this being done, however. It sounds useful, though, especially on the d...	If no thrust vectoring is installed, the aircraft will be uncontrollable in its initial ascent.
Why do airline pilots have shoulder harnesses? On airliners, passenger seatbelts are simple lap belts. However, flight crews seem to have at least shoulder straps, and often five-point harnesses. Why do flight crew have more restraints? <Q> pilots need to be able to do work during turbulence. <S> passengers don't re...	There have been some "unusual attitude" instances where the crew have recovered the aircraft but would have possibly been thrown from their seats or unable to reach the controls through excessive G if not fully restrained.
Why are commercial airplanes painted at all? While there was debate over why airplanes are painted white and a question about how much a new paint job costed , what hasn't been asked is why airplanes are painted at all. I remember one airline company sent out a press release in the 1980s or 1990s that keeping its ...	Another interesting thing is, that planes are regularly repainted to keep the drag low. So the painting reduces the fuel costs, instead of increasing them. They are a major part of brand recognition.
Why are number of landings logged? I have flight logs for a WW II B-24 navigator who flew with a combat crew in China Burma India. There is a column for number of landings. The entries range from 1 to 5 or 6, mostly 1 or 2. The time can be as long as 8:00 to 10:00 or more. Why is the number of landings recorded? I...	Landing an aircraft can typically be the most stressful regime of flight in terms of loading of certain bits of the aircraft, so it is pertinent to log how many times it happens per flight.
What is a vortex generator? I saw a vortex generator mentioned in an aircraft listing. What is a vortex generator? <Q> The angle of the plate causes the air to swirl, creating a vortex behind it. <S> This effect allows the air flow to remain "attached" to the surface even at points where the flow without a vortex woul...	To be more general, a vortex generator is a small angled plate installed on an outer surface of an aerodynamic body.
Why can't I exactly match the same points on different VFR sectional charts? I am taking a trip from somewhere on the Phoenix sectional up to the grand canyon. I wanted to just splice the two sectionals together on my computer and then print them out. I picked a coordinate to align (as you can see in the first image)...	Any two contiguous charts might or might not be rotated at the same angle;charts directly north or south of each other (several pairs along thenorthern edge of the 48 states) might be aligned, but other pairs of chartsthat have an east-west offset (most of the other adjacent pairs)are likely to be rotated at a differen...
What does "radar contact" mean in ATC calls? When ATC mention 'radar contact', what does that mean? In what conditions ATC might contact you and mention 'radar contact' in the call? and what would be the appropriate responses? <Q> The FAA's Pilot/Controller Glossary gives both US and ICAO definitions: <S> RADAR ...	“Radar identified” An expression used by ATC to inform the pilot of an aircraft when radar identification is established.
What's the advantage of using short wings rather than long wings? To clarify the question, I mean the type of wing used on a Concorde or a fighter jet, vs a glider's long and thin ones. What is the aerodynamic reason for using a short wing when the plane is faster? <Q> Another reason to have shorter wings on high-speed...	So for the same lift, a shorter wing would be lighter, but study have shown that lift is not generated on the full span of the wing, so a short wing would not be efficient.
Can a commercial cargo aircraft be converted into a commercial passenger aircraft, and vice versa? Just saw a video in a news, a military cargo plane carrying people stranded in some country. The seats were like in a commercial airliner. This led me to ask the question. Would it be possible to see some examples where ...	There are such a thing as "Quick Change" aircraft, allowing entire 'pallets' of chairs to be exchanged for cargo.
Why don't big airliners have bigger doors? Reading this question I saw this picture in MikeFoxtrot's answer and noticed how easier it would be to board the plane using that huge door: I understand that for single aisle planes you wold need to form a single line anyway, but for two aisle planes having a wide door ...	This helps under the structural viewpoint: the presence of a door (cargo or passenger that might be) induces design problems that are amplified if the compartment has to be pressurised.
Does an A320 revert to Direct Law if both engines flame out? In the case of a flame-out in both engines on the two-engine A320, does the aircraft revert to Direct law or does it maintain Normal Law ? An example is US Airways 1549 (the landing on the Hudson). <Q> The airplane needs a primary source of electrical po...	The airplane will no longer be in normal law mode if both engines fail and no other electrical generator is online.
How should I deal with a passenger experiencing hypoxia over the Grand Canyon? I am taking my mom for a trip over the grand canyon. My mom lives at sea level, whereas I live at 5000ft, and workout at 8000ft daily. The VFR lowest route over the Grand Canyon is 11,500ft MSL. If I am flying over this with my mother and s...	If a full oxygen system isn't an option bring one or more "boost cans" These can provide temporary/limited relief for symptoms of hypoxia – probably enough to get yourself back on the ground, or at least to a lower altitude. At 11,000ft it's unlikely lack of oxygen will make your mother really ill Just get the suppleme...
Why do propeller blades not have winglets? On the first look this question might sound ridiculous and maybe it is. But as propeller blades act by the same physical laws as wings, and winglets reduce the induced drag by quite a bit, then why are they not put on propeller blades? I could imagine that it might be a mate...	I'd say that one of the reasons for winglets in wing tips is to reduce the marginal vortex, due to the compensation of the difference in pressures between the upper and lower surface of wing, this 'vortex' or 'swirl' increases drag, and thus impairs overall airplane efficiency.
What are the advantages of Chemical Oxygen Generation over Gaseous Canisters on board of aircrafts? I'm looking to get a bit of info on Chemical Oxygen generation, especially as done on aircraft. I understand the process of Chemical Oxygen Generation. I'm also aware that weight for weight it produces far more oxygen th...	The chemical generator is cheap, doesn't need frequent maintenance and checks, and can supply oxygen for a larger number of people without adding weight to the aircraft because the oxygen is a byproduct of the burning of Sodium Chlorate. Minus points are they are single-use, time-limited and cannot be shut off.
Why is a control surface that allows two sides of airflow better than those that allow one? For example, ailerons allow air to flow past both the top and bottom surfaces, which makes it more aerodynamic than speedbrakes. Also, plane rudders have air flowing on both sides, which is apparently mote efficient than a spoil...	With control surfaces you want to alter airflow with out creating excess drag.
How might one start a new logbook for an engine that had one lost? About 6 months ago in a hangar at a local (KLWT), I saw a Piper PA-30 Twin Comanche and instantly wanted it. When I got home, I did a look up on the Registration (N) number and found out that the aircraft was de-registered in 2005. I did some askin...	For an engine or prop, you can simply start a new log with the appropriate explanation as the first entry.
Is there a fuel injector cleaner additive available? I have not seen any additives (such as those used in automobiles) to clean and maintain fuel injectors in aviation engines. Is there a reason for that such as the use of lead in 100LL or something else? The fuel injectors will eventually constrict or clog as the ...	I'm not aware of any FAA-approved (or FAA-accepted) products for on-engine fuel injector cleaning.
Do French, Spanish, Italian, and Greek controllers still speak to their native pilots in their native language? At the time of my retirement in 1999, controllers in France, Spain, Italy, and Greece typically spoke to their native pilots in their native language in spite of the fact that English was/is the international...	The rules of air indicates that the ATC must be able to speak english if they have to deal with international traffic. The French language is used (except for training purposes or particular cases) between French pilot and ATC
Are all the engines on a multi-engine plane the same? In general, are there any differences between the engines on a multi-engine aircraft? Are engines designed to be specifically for the left or right wing, or inboard or outboard for a 4-engine aircraft? What about the tail engine on a tri-jet like the DC-10? Is it t...	Usually the Engines on the same plane are of the same model (or type).
What is propeller / engine sync and how does it work? In some models of multi-engine airplanes there is a switch labelled something similar to "prop sync" or "engine sync". My questions are: What is engine synchronization? How is it achieved? Why is it important to use? What happens if you don't use it? <Q> I don...	In aviation, propeller synchronization is a mechanism that automatically synchronizes all propellers of a multi-engine, propeller-driven aircraft so that they rotate at the same speed.
Are there risks if the side joystick must be handled with a pilot's weaker hand? Suppose that a first officer were left-handed and a captain were right-handed. Both are NOT ambidextrous. Even after training, what if their weaker hands' control and degree of versatility remain worse than their dominant hands'? In ot...	In fact, most pilots learn to fly with their non-dominant hand, even in aircraft with traditional yokes.
Is there a cockpit which can recognize the voice of the pilot and help him/her to fly? Is there any new cockpit that uses voice commands (think for example Siri from the new iphones) that can identify the voice of the pilot and help him/her to fly? <Q> Voice recognition works because it learns from the user over time, ...	No, voice recognition is currently not used in aircraft as it would have to be built into the aircraft to pass certification for the aircraft and with rotating crews on aircraft, the voice recognition would need to be able to work with too many different voice types: high pitch, low pitch, male, female, accents, dialec...
Are there items bigger than an aircraft section transported by air today? This question about engine transportation made me wonder what is the size of the biggest item ever transported. Then I remembered that it should have been a space shuttle (either Buran or the American Space Shuttle ), but those items are no ...	On 11 August 2009, the heaviest single cargo item ever sent via air freight was loaded onto the Antonov 225.
Would it be viable to install a screen in front of jet intakes to prevent them from sucking in birds? Why isn't there a protective screen with large diameter holes (approx 2') mounted in front of the jet engine intake to protect the turbine blades? This would keep larger birds and large ground debris from getting suck...	Screens were actually used on the first prototypes of the Me-262 , but soon abandoned when they were found to be more of a burden than a help. A few Russian/Soviet fighters had retractable FOD screens on their engine intakes (MiG-29 and Su-27 IIRC).
Why should I request a long landing? I fly in/out of a small international airport occasionally, the runways are quite long. It is not unusual to land half-way or even three-quarters down the runway. When doing this, pilots request long landings from ATC. I once did not request a long landing and did anyway and got ch...	In EASA land, you can also be asked to make a long landing because the controller will want to clear another aircraft to land behind you, although you are still occupying the runway. I don't think it is documented anywhere that you must inform the controller if you want to land long.
Can a drone hitting a plane be mistaken for a birdstrike? Could a bird-sized consumer drone be digested by a jet engine, and not be recognized as a drone, mistaking it as a bird strike? I'm thinking of the situation during the flight - like an engine making a short unusual noise, but works OK; not sure that can even ...	One might suspect that a lot of damage with no smell seems unlikely to be a birdstrike, but there are cases where some engine component has failed & caused engine damage (ranging from barely noticeable up to catastrophic), and you can't really know much about causality for the engine doing what it's doing until you're ...
Why is full carb heat recommended when reducing power below normal setting? In my first flight lesson today, my instructor asked me to apply full carburetor heat when we had to reduce power to 1900 RPM in our Cessna 152. I was surprised by this as I didn't remember learning this in ground school, and I later checked t...	I learned that applying carb-heat when throttling down has nothing to do with Carb-Icing, but instead is to prevent shock-cooling.
Is there an aircrew bunk in the 747 cockpit? Reading this article , I came across the quote : Pilots also enjoy its creature comforts: at BA the 747s are known as the ensuite fleet. “Our little bedroom is within the cockpit: you can stick your pyjamas on and clean your teeth without anyone seeing you. And coming ...	I've seen references that the 747 had a lot of different plans, with many airlines having a crew rest area in the rear of the upper deck rather than off the cockpit.
What are the indications that your turbofan engine has "thrown a blade?" In an airliner, such as an A380, what indications do the pilots have that an engine has thrown a fan blade? Will that always result in destruction (of the engine)? <Q> Turbofan engines are designed and tested to contain a fan blade failure . <...	If you lose a "large" blade like a fan blade, or a "heavy" blade like most turbine blades, the engine vibration monitors will instantly go off the scale and the engine control system should shut the engine down automatically.
In what circumstances could a 787 stay powered on continuously for 248 days? The FAA has issued an airworthiness directive for the 787 : SUMMARY : We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 787 airplanes. This AD requires a repetitive maintenance task for electrical power d...	They are also powered off if the expected time at the gate is long.
What is the difference between slice, segment and leg? I have heard of the terms slice , segment and leg . Since I am a newbie in travel industry, I would like to know and understand the basic differences between the three. Could someone please explain the three, using some kind of example? <Q> I'm pretty sure th...	A flight segment can include one or more legs operated by a single aircraft with the same flight designator.
What is Transponder Code 2000 actually used for? On What is the significance of a squawk code? @DeltaLima gave a fairly concise answer. In it he listed several 'standard' codes used for things like emergencies. Also in the list was Code 2000, for which he included the description: Used when entering a Secondary ...	Another use of code 2000 is on the airport: before power up you can select code 2000 to avoid code conflicts that could occur when you would maintain your code from a previous flight.
Is there a database of airport ceilometer raw data? I am interested in obtaining raw ceilometer data, to test some cloud/aerosol layer identification algorithms. Is this type of data freely available or will I need to ask for it directly from the airport? Do airports keep an archive of raw data or simply of cloud he...	My favorite weather site Weather Underground has historical data.
What makes flight recorders harder to find than tagged sharks? It really bothers me that we can't find planes that weigh tons with black boxes (AFAIK) technology that's almost obsolete, on the other hand shark tags (AFAIK) work great for long time and we can monitor shark movement, depth, temperature, etc., all the tim...	A shark tag doesn't have to survive a 500mph impact ( #7 on the list ) with the ground, and a flight recorder has to be able to do so. All of these differences combined mean that black boxes are manufactured to much higher standards, and as a result they are bulkier, have different sorts of radios and require much more...
What is the function of the tail section on a fixed-wing aircraft? In a generic fixed-wing aircraft like a Cessna, what is the function of the tail section, i.e. the rudder and elevators? <Q> First off lets be clear that a tail section does the same thing on small aircraft that it does on large aircraft. <S> Second ...	The vertical tailplane, also called vertical stabilizer helps the aircraft's nose facing into the direction of the relative air flow.
What is different between a Cat IIIA, Cat IIIB, and Cat IIIC ILS approach? In terms of aircraft equipment, approach minimums, procedural differences, and anything else relevant, how do the 3 types of a Cat III ILS differ from one another? <Q> ICAO and FAA CAT III definitions <S> A CAT III operation is a precision app...	A category III C approach is a precision approach and landing with nodecision height and no runway visual range limitation.
How do manufacturers engineer their aircraft to deal with tail strikes? I have been told that tail strikes on take off and landing are rare but do occur. I think, in my mind, the tail touching the ground at all would just make the tail fall off, but it appears I was wrong. In most of cases of tail strikes I've read...	And some models of the 737, 767, and 777 have a tail skid that prevents damage from most takeoff tail strikes.
What are N1 and N2? When I'm reading something about jet engines, it's common to see references to N1 and N2. I've never fully understood what N1 and N2 are on engine instruments and how they relate to thrust and the position of the throttle. <Q> N1 and N2 are the rotational speeds of the engine sections expressed as...	The N2 is the engine core, and the N2 gauge is used mainly during engine start: on initial starter engagement, the N2 starts turning first, and things like adding fuel+ignition and then later disengaging the starter are based on specified N2 speeds.
Regarding N1 and N2, what does the "N" stand for? I initially phrased this question in a comment to another question regarding what N1 and N2 mean, hoping it would be that sort of low-hanging fruit that is easily answerable and not worth a proper question in its own right. But then I starting searching and came up...	As far as I can tell, the N comes from the physics behind turbines in general, whether they be water pumps or wind turbines, a subset of mathematics called fluid dynamics .
Why don't most fighters have thrust reversers? With the exception of the Panavia Tornado, fighters do not have thrust reversers. Why is this? Why does the Panavia Tornado have them? <Q> It is not a very efficient means to reduce the speed of a landing aircraft either, and other methods (e.g. brakes or drogue parachute...	Military large airlifters use thrust reversers to quickly unload and return for more, and to land on short runways; that's rarely a concern for a fighter. Thrust reversal is a complex system (equals money) and it uses significant amount of fuel (also equals money).
Is wing flex good? I've noticed that the wings of the 787 and A380 tend to flex a lot. Does wing flex help an aircraft in any way? <Q> The wings of the Boeing 787 are so flexible because its carbon fiber material can be stretched more, and the high aspect ratio of 11 will magnify this effect. <S> In flight the conseque...	Flex does increase the risks of things like fatigue cracking (metal), delamination (composite), excessive strain and aerodynamic surprises, but if these are all allowed for in the design then the plane will be lighter and have a better payload-range than the equivalent stiff wing.
Why is an unpressurized takeoff performed? Why would an aircraft perform an unpressurized takeoff? What conditions lead to this being beneficial? <Q> Typically, the pressurization system is run by engine bleed air. <S> Using that bleed air means you have less engine power available than is maximally available with the ...	One reason for an unpressurised takeoff would be if the aircraft's pressure hull is damaged, and it's making an unpressurised ferry flight to somewhere it can get repairs.
What is the purpose of a dorsal fin such as on the Boeing 737? I've noticed that the 737 has a rather unusual vertical stabilizer, with an extension at the front. Is the 737 the only plane equipped with such a vertical stabilizer, and what is its purpose? <Q> The "extension" at the front is called "dorsal fin". <S> Its...	Adding the fin extension or strake will keep the aircraft stable into higher angles of sideslip.
How should a pilot respond verbally to being cleared for takeoff? When ATC says "cleared for takeoff", what's the correct answer from the pilot? <Q> This is how FAA recommends (PDF) : <S> A typical takeoff clearance may state, for example, “(Callsign) <S> 123 RNAV to MPASS, Runway 26L, Cleared for Takeoff”. <A> ...	The expected pilot response is, “(Callsign) 123, RNAV to MPASS, Runway 26L, Cleared for Takeoff”.
Which airplane designs have the greatest longevity? What airplane designs have been around the longest, from first flight through last retirement from active commercial or military service? My guess is that the DC-3 will win, since it has been around since before WW II and is still in service, although there are enoug...	There's a de Havilland Dragon Rapide still in commercial service doing air tours around London, that's first flight was in 1934. The USAF B-52 first flew in 1952, stopped production in 1962, is still a frontline bomber, and is projected to continue service until 2045 http://en.wikipedia.org/wiki/Boeing_B-52_Stratofortr...
Why does the Harrier jet have four landing gears? I was looking at pictures of Harrier jets and I noticed something. They have four landing gears. That seems pretty unusual for a fighter jet - most have only 3 in a triangle formation. What is the reason for this 4 point configuration? It seems to just add complexity...	This allows the gear to be lighter, stay close to the center and out of the way for the jet blast.
Why is the nacelle outlet of the tail engine of the L-1011 Tristar lower than the engine itself? I've noticed that the nacelle outlet of the Lockheed Tristar is situated below the engine itself. It is at the end of the fuselage. The nacelle outlet of the tail engine of the DC-10 on the other hand, is at the same height...	In this cutaway you can see the intake duct leading down to where the engine is: Source Putting the exhaust nozzle lower allows more room for rudder above it.
Why do English-speaking pilots and ATC say "Niner" instead of "Nine"? Besides the fact that it's now a standard, why do American-English-speaking pilots and ATC say "Niner" instead of "Nine"? None of the other numerals are pronounced in an atypical fashion. For what was "Nine" being mistaken that resulted in the "Nin...	Some non-native English speakers have trouble both pronouncing and understanding the "TH" sound. Nine / NinerGerman is a commonly spoken language, and "Nine" is "No" in German.

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