Questions for mei's

Mavmb

Well-Known Member
Questions for mei\'s

What is the best way to fail a student's engine, just using the mixtures? If the engine is warm, do you just pull the throttles instead? I know the fuel selectors are an option too. And do most of you feel comfortable about completely shutting off an engine and feathering the prop for a student? I've met some instructors who don't like to feather the prop, although I think it seems fine if you have enough altitude and are close to an airport.
 

Eagle

New Member
Re: Questions for mei\'s

in general you should not shut an engine off, the MEI should have an idea of what simulates dead eng feathered and non feathered.

two reasons for this.

1. you shut one engine off, what do you do when the other one craps out? does your single eng CFI pull the mixture to test your eng out in the 152?

2. most engine failures will not be a total shut down, most will be the pilot seeing he/she needs to shut it down. unless of course there are sections of engine hitting the tail.


and keep inmind. tooling around in a piston engine at 2500 rpm, and shutting the eng off fast at -10C can't be good for it.
 

turtle

New Member
Re: Questions for mei\'s

Eagle ... question for you:

</font><blockquote><font class="small">In reply to:</font><hr />
... and keep inmind. tooling around in a piston engine at 2500 rpm, and shutting the eng off fast at -10C can't be good for it.

[/ QUOTE ]

It seems that some airplanes (Duchesses &amp; Seminoles) don't really mind a complete shut down. At Pan Am we would do a complete shutdown/feather and the engines didn't seem to suffer any long term effects (of course, having brand new airplanes helps!).

At ATA, however, we started using Aztecs for Commercial training (including the usual engine shutdowns) and these airplanes definitely DO NOT like it. I've watched the number of engine problems in our fleet rise astronomically since we've started doing this. (Of course, now we're on the other end of the spectrum - these airplanes are old and tired).

My question is, what makes some engines so sensitive to sudden power changes &amp; shock cooling and others seem unaffected. (Another example is with high performance airplanes. I'm not completely familiar with the procedure but I know on these airplanes you can only reduce MP by about 2" per minute to keep the engine warm. In a light trainer if you want to come down quickly you just pull the throttle to idle. Why the difference)?
 

Eagle

New Member
Re: Questions for mei\'s

well first things first. there is no such thing as shock cooling. If there were wouldn;t the engine shatter into a million pieces the first time you flew into a rain storm?

http://www.avweb.com/articles/shockcoo.html

I am thinking more along the lines of jut the wear and tear on the airplane's engs, and the torque when you shut them down, you know how they shake like a wet dog? thatis torque on the engine and it's componants.

I suspect (don't know) the problems with the engines are specific to the engines themselves. TCM vs LYC, IO vs O, and the accessory packs, all play in.
 

StephenCFI

New Member
Re: Questions for mei\'s

</font><blockquote><font class="small">In reply to:</font><hr />
What is the best way to fail a student's engine, just using the mixtures?

[/ QUOTE ]

1) Throttle to idle. Instead of feathering, add power on the "dead" engine to about 12"MP, which simulates feather pretty well.

2) Mixture to idle cutoff or fuel selector off. I'll only do this above 5000AGL, with a more experienced student. Fuel selector is more realistic (easy to reach down in the Seminole and shut it off without the student knowing, and all the levers in the quadrant are in the normal places, so no hints about which engine is out) but it is harder to restart.
 

pavelump

Well-Known Member
Re: Questions for mei\'s

</font><blockquote><font class="small">In reply to:</font><hr />
does your single eng CFI pull the mixture to test your eng out in the 152?

[/ QUOTE ]

mine would turn off the fuel when I wasn't looking.


Dave
 

panampilot

New Member
Re: Questions for mei\'s

Anytime we're below 3,000 feet AGL we only simulate engine failures with reduced power and then set simulated feather power on the dead engine. This works well with engine failures while still on the runway and in the pattern. Above 3,000 feet AGL the fuel selector or mixture is used. I prefer the fuel selector to surprise the student.
 
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