Suspect there are more planes damaged in touch and goes, experienced pilots included, than in regular end of trip landing accidents. Always rather surprises me that we spend so much time doing the most dangerous bit. This seems speciallyto happen to 'on water' touch and goes.

I was thinking after posting last night, I'm not too worried about pushing the rudder over and then seeing how she flies on the ailerons but I am a bit nervous about pushing the ailerons over and seeing how she flies on rudder. How far do you let it go before you give up?

Well I'd guess that if the ailerons or the rudder lock up in flight, they can only lock up in the position they're in at the time. So the maximum position the ailerons could lock in is only the maximum aileron input you use in flight. So you wouldn't ever have to cope with the ailerons locked in the full position. Someone correct me if I'm wrong.

Also flying with the rudder locked in position could be dangerous, as everytime you turn against the direction of the rudder you\'ll sideslip and end up with a very high rate of descent. So I suppose just make all turns in the same direction as the rudder deflection.

Isn't it much more likely that they would simply stop responding to control input but still be free to move rather than "lock up"
assuming that they were either cable or pushrod controlled then they would work right up untill the cable finally broke or a loose bolt fell out at which point they would be likely to be free to move.
The control column doesn't just move the control surfaces it also holds them where you want them.

So how could you continue to fly with freely flaping control surfaces?

Would the control surfaces "castor" with the airflow like the steering wheels of a car when being towed? therefoer making it possible to control the aircraft?

Much better brains than mine needed to answer this methinks.

Sorry I was wrong about what I said, your right. So if they're free to move they could flutter and over stress the airframe :}

I, too, think this thread is invaluable.

There is, however, a limit to how sensible it is to practice (or should I say overpractice) emergency situations. I think we have looked in general at specific problems, and how they could be mitigated in order to make a safe landing. Many problems, though, will manifest as a combination of several individual events.

I suspect, therefore, that what we should concentrate upon is to establish the principles of mitigating system failure, so that multiple systems failures, or indeed a single system failure manifesting in a way differing from those we have practiced, can be survivable.

A long-winded way, perhaps, of saying don't just practice, think as well.

An interesting question is this: when a control failure happens, what should your initial reaction be?

For example, on this thread we've touched very briefly on the difference between a jammed control (not impossible if the previous pilot "forgets" to mention that he lost his pen, and it finds its way into the control mechanism), and a fluttering control (again, not impossible if the control cable snaps). So to simply talk about "aileron failure" doesn't give us the full picture.

If you were to realise that the ailerons had "failed", how would you go about determining the nature of the failure? Would it be a good idea, for example, to climb up to a safe height, and experiment at various different airspeeds, to see how the other controls react, especially as you slow down (after all, you will need to slow down to flare and land at some point)? Let's assume it's day, and good VMC.

If we agree that it's going to be necessary to explore the nature of the failure before attempting a landing, then maybe we could argue that it's a bad thing to practice this type of failure too much beforehand. After all, if we practice one type of failure, and then another similar but different failure happens, would we be likely to make (possibly incorrect) assumptions about how the aircraft will react on landing, based on our previous practice, and therefore not spend as much time exploring those controls we have left as we ought to? Would it not be better to have not practiced any type of "generic" control failure, but instead to find out the exact nature of a control failure when it actually happens?

Before you answer, though, what if the control failure happens at night? Or in IMC? Maybe now it's not quite so appropriate to try to explore the failure when it happens? And how about rudder failure - would we want to risk stalling the aircraft, even at a safe height, knowing we have some kind of rudder failure and may not be able to avoid or recover from a spin?

Just food for thought - I don't know the answers, I'm not even sure if there is actually a "correct" answer..... My only experience was a flap failure, at night, last year. I considered taking the aircraft up to a safe height to explore the low-speed envelope before landing, to make sure I didn't get any unexpected wing-drop. But since it was night, I decided this was more dangerous than just attempting a landing and seeing what happened. Turned out the flaps were both deployed evenly, so no adverse effects on landing, but I couldn't be sure of that until I landed. I think I'd probably handle the situation the same way if it happened again.

FFF
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FFF, I don't have an authoritative answer but present the following. An Alaskan Airways MD83 had a loss of control back in 2000 which resulted in loss of all lives on board. I mention this because a lot of work was done on investigating the accident with an NTSB Report (pdf) which makes interesting reading.

(Just reread it and edited to add this)

Recommendations include..

So you ask "Would it be a good idea, for example, to climb up to a safe height, and experiment at various different airspeeds, to see how the other controls react, especially as you slow down (after all, you will need to slow down to flare and land at some point)? "

From my reading of this recommendation, which may well be wrong, I would say you shouldn't. There aren't checklists for these things in spamcans, so don't be a test pilot and if it flies well enough to get it to altitude, it flies well enough to get it on the ground ASAP.

If, say an Aileron control cable breaks it would probably be the one under most tension, ie, "down" for that aileron.

Result (by deduction) 1) that aileron flaps up until the airflow over it is neutral, 2.) That wing drops 3.) The pressure against the underside of the opposite aileron is no longer balanced and will be felt at the stick.

If you release the pressure on the stick the second aileron too will rise until it is airflow neutral. Hopefully the plane will then be at some kind of stability. You will still certainly be able to roll towards the failed aileron, I guess whether you can roll the other way will depend whether the airflow neutral position of an aileron is all the way up or just part way, probably depending on plane. If you can achieve this stability you might get home on the rudder.

Stuck aileron ( by foreign object) is different and probably more likely, but I'm just thinking out loud here about what we can consider logically.