Can helos survive control failures?

Pi1otguy

Pi1otguy

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Fox McCloud
If a helos has a control failure (similar to a snapped ruder or aileron cable on a fixed wing) can it survivably land?

Does the use of hydraulics systems change the procedure or likely outcome?
 
Depends on the helo. The Huey (UH1A) has hydraulic assist. So if you lost a hydraulic system you can still control the helo. I know in the Huey sim that I had a heck of time trying to maintain a hover without the hydraulics though. Other helos become a dead stick when the hydraulics go out. Shaft failures are another problem that leads to an immediate landing.
 
It depends on the helicopter as Scott correctly said and type of control failure. Just to add what Scott said about the Bell aircraft that have the hydraulic assist is that you don't hover them without hydraulics. You would perform a run-on landing and use the skids. Basically there are rods that form a solid mechanical linkage from the stick to the rotor...which if you have a problem with the actual linkage treat it as a control malfunction.


If there is any clue in flight that you have a control malfunction, you land as soon as possible and perform an emergency engine shutdown. It might be felt as sloppy controls, vibration, uncommanded actions....get it on the ground and shut it off....keep everyone in the helicopter because you don't want someone to get wacked by a rotor blade on the way out (something that should be covered in the passenger brief).

Now in a UH-60 and other bigger heli's there may or may not be a direct mechanical linkage to the rotor system. It really don't matter because even if you had Superman strength to actually move the controls you would just bend the control rods and cams and you couldn't move them with precision enough to maintain control of the helicopter. That is why there is a backup system...in fact in the 60 there are two independent primary servos that work continuously as you fly with a backup pump system ready to kick in if one pump goes out or if you have a leak (which leak detection will usually isolate for you). This makes a system that is virtually bulletproof...pun intended. :yes:


So lets say you have a really bad leak in both servos and all your hydro. fluid is to be gone in and a matter of moments and your flight controls lock up....you know they say "fly the aircraft no matter what happens"...this is one case you can unbuckle and sit with the passengers because you are one...(we do this in the sim. and try to descend using rotor RPM and the stabilator but it usually results in a condition that my wife would be better off financially.) :cheerswine:


With all the variables its tough to give you a straight answer...some heli's might do fine where others will not but they will usually have a system that is really reliable.
 
Another reason for the quote "I used to be scared to fly in helicopters. Then I learned how they worked. Now I'm scared when I see one overhead!".
 
It also depends on the control failure. Breaking a main rotor pitch link is a lot more serious than losing tail rotor control.
 
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