Correct, it is a recommendation of Lycoming to use the mixture.
It's also very easy for a student to identifie the correct engine when there is only one throttle to play with
That is a selective quote. In fact Lycoming Flyer Key Reprints magazine published an NTSB Warning of the dangers of cutting mixtures at low altitude to simulate engine failure.
Read on:
Warning on Simulated Engine-Out Manoeuvres.
“In mid 1976, the NTSB issued an urgent warning to all pilots simulating an engine-out condition on multi engine airplanes, to eliminate actual engine shutdown and substitute instead reduction of power at low altitudes such as traffic pattern. The recommendation resulted from the NTSB investigation of the fatal crash of a light twin in which a flight instructor and an applicant for a multi-engine rating were killed. The Board’s investigation revealed that some flight instructors do use the fuel selector or the mixture control to shut down an engine to test a multi-engine applicant.
The NTSB observed that the use of such procedures at traffic pattern altitude may not permit instructors time enough to overcome possible errors on the part of the applicant. The recommendation by the NTSB means that all simulated engine-out operation at the lower altitudes will have to be accompanied by retarding the throttle and unless this is executed slowly and carefully – engine failure can result. Many flight instructors down through the years used the technique of abruptly cutting an engine with a multi-engine candidate to test his emotional reaction and judgement with this extreme technique…..however, any practice on simulated engine-out condition at low altitudes should be best accomplished by a slow retardation of the throttle in accordance with the NTSB recommendation. This careful technique will protect the engine, and at the same time provide for instant power if it is needed”.
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The NTSB viewpoint was shared by the British CAA who published a similar argument for throttle closure in their AIC 52/1999 (Pink 193) date 6th May 1999 and titled “Guidance to Training Captains – Simulation of Engine Failure in Aeroplanes. Quote in part: “Generally the throttle may be initially moved smoothly to the closed position; the mixture control or Idle Cut-Off should not be used to simulate engine failure. Reference to the engine manufacturers should clarify the technique in particular cases. When the trainee has identified the “failed“ engine and completed his “touch only” feathering drill, the throttle should be advanced to the zero thrust position”.
The Piper Seminole Information Manual at Section 10, entitled Training Tips states:
“Experience has shown that the training advantage gained by pulling the mixture control or turning off fuel to simulate engine failure at low altitude, is not worth the risk assumed, therefore it is recommended that instead of using either of these procedures to simulate loss of power at low altitude, the throttle be retarded slowly to idle position”.
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Flying school operators with PA44 Seminoles who still teach mixture cuts after take off to simulate engine failure would be legally wise to heed the warnings against the practice published in their own POH
