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An aircraft is flying in cruise flight on a long distance flight. The autopilot is turned off. The only occupant of the aircraft is the pilot.

Suddenly that pilot dies, what will happen?

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closed as too broad by SentryRaven, Simon, Jon Story, DeltaLima, fooot Jan 29 '15 at 15:32

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ This question is very broad - can you give a more specific context to the question? Or at least remove some ambiguity? eg in this scenario do we assume that the pilot dies without moving the controls or holding them in position? Is the aircraft assumed to be trimmed in level flight? $\endgroup$ – Jon Story Jan 29 '15 at 13:55
  • $\begingroup$ @JonStory, Yes, aircraft is flying in right direction and pilot dies sudden. $\endgroup$ – Hemang Jan 29 '15 at 13:57
  • $\begingroup$ it will crash eventually? $\endgroup$ – dalearn Jan 12 '17 at 16:03
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It has happened before that the single pilot lost consciousness while flying. What then happened is that the plane just went on until out of fuel after which it will glide down and skid to a stop (pilot survived). This is assuming there is no obstacle in the way.

Another example is the cornfield bomber, a fighter pilot eject and the plane still under power just kept going in a straight line and "landed" in a field.

A more deadly example is the helios flight 522. A mistake in the pressure regulation setting let the plane become unpressurized while climbing to cruise altitude. Both pilots lost consciousness and the plane's autopilot followed its programmed path following the waypoints and ending up in a holding patter until it ran out of fuel and crashed into the ground.

Survival depends on luck with obstacles, whether the plane is properly trimmed and which order the engines flame out in, asymmetric flame-out may result in a spin.

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  • $\begingroup$ Note that the first example in this answer assumes that the aircraft is properly trimmed for level (ish) flight, and that it is able to slowly descend, or trimmed such that it will gently descend when losing power... most aircraft will not be nicely trimmed, and without auto-pilot will usually crash. $\endgroup$ – Jon Story Jan 29 '15 at 12:22
  • $\begingroup$ @JonStory: Depends on autopilot type. Many (in large aircraft probably all) adjust trim now and then so the plane is not too badly out of trim when the autopilot is disconnected. $\endgroup$ – Jan Hudec Jan 29 '15 at 16:52
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    $\begingroup$ There was that jet with the golfer in it, they thought decompression or something, took out everyone in it, it flew for hours North. $\endgroup$ – CGCampbell Jan 29 '15 at 17:52
  • $\begingroup$ @CGCampbell: I think you mean the Payne Stewart crash. $\endgroup$ – Fred Larson May 27 '16 at 16:39
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Assuming no autopilot the plane will likely crash very soon as even if the airframe was trimmed at the time of pilot's death as there will be no mechanism correcting trimming on outer forces changes (turbulence, pressure change, etc.) Imagine a driver dying in a car - if the road is straight and wide, the car may go on for a while but as soon as there is just a small change in roads direction, uneven surface or even stronger wind, the car will crash quickly. Some planes may have features not directly tied to autopilot that correct piloting mistakes to some extent which may prolong the planes survival.

Also very important is what happens with the pilot's body. As long as the body doesn't interfere with plane controls, the plane will likely go forward longer. If, on the other hand, the pilot's body say falls on the controls, it may even disengage the autopilot if present and force the plane to make a move that will eventually go over its physical limits and results in spiral, stall, dive or disintegration in the air.

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    $\begingroup$ This is not correct. Most aircraft will fly (roughly) straight and level with no control inputs if they're trimmed for cruise flight. Of course, when the fuel runs out, it'll start descending. And this is without any computer assistance of any sort. This is due entirely to the aerodynamic stability designed into the airframe itself. There will be some oscillations, especially when the attitude is perturbed by turbulence, but they'll self-correct in most circumstances. $\endgroup$ – reirab Jan 29 '15 at 15:21
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    $\begingroup$ Also, the reason a driver will crash is that there are lots of things to crash into. If a driver dies in a wide-open area with almost nothing to hit, the car won't crash for a while either. $\endgroup$ – cpast Jan 29 '15 at 18:44
  • $\begingroup$ Aircraft trimming and leveling is what autopilot is supposed to do (if present), right? My understaning is that aircraft must be trimmed at any aerodynamic change of the environment, hence any pressure changes, turbulences or other fenomena will most likely result in unleveled airframe. That being said, I'm not a pilot so correct me if I'm wrong, please. The driver analogy was just an analogy, although there are many forces that can cause a car to crash even on what seems to be a straight road. $\endgroup$ – mikky Feb 3 '15 at 8:57
  • $\begingroup$ @reirab Aircraft typically have pitch stability although pitch oscillations may occur. Roll stability is another matter. At best, an aircraft might end up flying in a wide, wobbly circle, but could just as easily enter a spiral dive. $\endgroup$ – Anthony X Jul 10 '16 at 1:39

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