What do you do?

[Yenn]

We get training for things like engine failures, but recently I heard about the instructor who asked his pupil, what do you do if the throttle cable becomes defective on downwind, and goes to full throttle?

 

There were some good answers and one controversial one, but I wonder what the present company thinks.

 

The original question was about Lycoming type engines, but it could happen with a two stroke or a Rotax 912 type. Would the answers be the same for each type and would constant speed, or variable pitch prop need a different approach?

 

 

[djpacro]

It happened to me in the training area once. CASA FOI on board as my student. Turned the engine off, high short final.

 

 

[alf jessup]

Climb and gain sufficient height, ensure field within gliding range, shut down , turn off fuel and aim for 1st 3rd of runway and land normal like an engine failure scenario.

 

Not rocket science

 

 

[Marty_d]

Wouldn't it be better to be stuck full on than to fail? At least you can gain some height for a couple of minutes before cutting and gliding.

 

 

[alf jessup]

Wouldn't it be better to be stuck full on than to fail? At least you can gain some height for a couple of minutes before cutting and gliding.

Marty

The scenario is stuck full on throttle not failure

 

 

[Thruster88]

On a Lycoming you would control it with the red knob

 

 

[djpacro]

It happened to me in the training area once. CASA FOI on board as my student. Turned the engine off, high short final.

To add: we were obviously going very fast, from a gradual circling descent overhead Moorabbin, so quite different from the standard PFL practice with a glide approach. That word "high" was wrt the high speed and being able to ensure getting on the field, rather than "high" wrt my normal approach profile. Backup plan was to restart the engine.

[Yenn]

Are there any problems with controlling with the red knob, ie mixture? What happens if you are seriously undershooting. Full throttle, control rpm with mixture?

 

 

[Thruster88]

Are there any problems with controlling with the red knob, ie mixture? What happens if you are seriously undershooting. Full throttle, control rpm with mixture?

Yes just go back to rich if undershooting, lean cut when you have it made

 

 

[NT5224]

That happened to me once.

 

I had flown across the Dividing Range at about 9000 ft to stay above some cloud, and had been running at high rpm for an extended period. I descended normally at one of those airfields on the other side (can't remember which, 'Gondawonda' or something similar) and found my throttle had stuck open (not on full revs, but something high enough to make a braked deceleration difficult). Touched the aircraft down normally (albeit it a little faster than i would have liked), and just killed it with the Mags. Pushing myself clear of the runway, I gave the throttle spring a good working and oiling and never had the problem again. I suppose I could have killed it on base or long final but wanted to keep my options open as long as possible, just in case.

 

Alan

 

 

[facthunter]

Early rotary engines had no throttle. the "blip" switch IGNITION is triggered on and off. Very noticeable when taxiing. On an engine with a muffler this, (cutting the ignition and then restoring it) can explode the muffler or make some incredible backfires, which may actually damage the motor seriously if you are unlucky.. Where you have a mixture control that won't happen. Just cut it on the mixture, and you can kick it back in if you have to. It's not NICE to start an engine on full throttle but if it's that or prang do it. Some engines don't windmill either. Get high or fast (it amounts to the same to some extent.unless the plane is a poor L/D design. Get the plane to a place where the landing is ASSURED. Crazy to hit the NEAR fence at flying speed..

 

In all these "what IF's" it's a matter of working out what you have left going for you, like any kind of control failure and use what you have not what you are used too. Nev