Mixture cuts on take off revisited
Join Date: Apr 2005
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From reading the Lycoming statement, it does indeed explain why a mixture cut is preferable to throttle closure in order to simulate failure. It seems it's all about having the throttle wide open to "cushion" piston movement. What is not said, however, is that as part of the identification process (dead side dead leg, primary), the "dead" throttle is closed as a secondary confirmation.
And as soon as you close the dead throttle which is about 5 seconds after dead side dead leg, the "cushioning" advantage supplied by the wide open throttle is shot to pieces.
And as soon as you close the dead throttle which is about 5 seconds after dead side dead leg, the "cushioning" advantage supplied by the wide open throttle is shot to pieces.
Join Date: Jun 2001
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No offense here an3_bolt, and I agree with everything in your most recent post. I agree too that low-level mixture cuts are somewhat risky.
It's actually because I have tried to put a lot of thought into this issue that I dislike the oversimplification of "throttle good, mixture bad".
My current employer discourages mixture cuts at any stage in flight, but makes no comment about rapid throttle cuts at as low a height as you like. In terms of pilot education, I think that we can do better than that.
Cheers again,
O8
It's actually because I have tried to put a lot of thought into this issue that I dislike the oversimplification of "throttle good, mixture bad".
My current employer discourages mixture cuts at any stage in flight, but makes no comment about rapid throttle cuts at as low a height as you like. In terms of pilot education, I think that we can do better than that.
Cheers again,
O8
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Something for the student's.
If you think or feel what is happening is unsafe -SPEAK UP. Don't take the person sitting beside you as god. There are those out there with a God complex, and have derived their own parameters, gold bars do not mean quality/experience. Understand everything that is going to happen thru the flight. The old rule - not briefed - not done. If they pull something on you, that you feel is not right - SPEAK UP.
Something for the Instructors
Thankfully there a more good and safe teachers than there are these -
"oh but they have to see what happens when you have a double engine failure with no flaps or gear and your in cloud with 40 knots crosswind and fouled controls". Sadly I have met some.
A bit rough I know, but Safety first, ego last.
If you think or feel what is happening is unsafe -SPEAK UP. Don't take the person sitting beside you as god. There are those out there with a God complex, and have derived their own parameters, gold bars do not mean quality/experience. Understand everything that is going to happen thru the flight. The old rule - not briefed - not done. If they pull something on you, that you feel is not right - SPEAK UP.
Something for the Instructors
Thankfully there a more good and safe teachers than there are these -
"oh but they have to see what happens when you have a double engine failure with no flaps or gear and your in cloud with 40 knots crosswind and fouled controls". Sadly I have met some.
A bit rough I know, but Safety first, ego last.
Join Date: Feb 2003
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A37575
To further explain the difference between the throttle closure over the mixture. It is realy rapid closure of the throttle that damages the engine when a throttle is closed rapidly from full power the fuel is still pumping out at a rapid rate now being un-burnt and pumped into your exhaust system. Suddenly bang as it ignites blowing your exhast system apart or worse damaging your engine or causing a fire.
My bill was for a new baffle assembly and inspection I do not need specific proof I have been working as a LAME/AME for over 26 years. It happens not often but it happens, the nature of simulated eng failures usually has an element of surprise to get the surprise the action is often rapid closure.
The real issue is at what time it is done, I have never seen the need for any low level practise, actual failure is rare and we are dealing with assymetric flight which can be simulated at higher levels using the hard deck method the military have for their combat training.
To further explain the difference between the throttle closure over the mixture. It is realy rapid closure of the throttle that damages the engine when a throttle is closed rapidly from full power the fuel is still pumping out at a rapid rate now being un-burnt and pumped into your exhaust system. Suddenly bang as it ignites blowing your exhast system apart or worse damaging your engine or causing a fire.
My bill was for a new baffle assembly and inspection I do not need specific proof I have been working as a LAME/AME for over 26 years. It happens not often but it happens, the nature of simulated eng failures usually has an element of surprise to get the surprise the action is often rapid closure.
The real issue is at what time it is done, I have never seen the need for any low level practise, actual failure is rare and we are dealing with assymetric flight which can be simulated at higher levels using the hard deck method the military have for their combat training.
The company I worked for specified mixture cuts for simulated engine failurs except for AFATO below 500' when the throttle should be used. In this case I close the throttle smoothly and slowly. You know if you have closed the throttled too rapidly if it pops and farts. I didnt know it was fuel actuallyburning in the exhaust system, that quite scarey.
