Originally Posted by
Judd
Those who have followed the discussion on the Conquest 441 accident at Renmark would note that much of the comment revolves around the possibility of a practice engine failure after take off gone wrong.
The following link sent by a reader on the thread is a relevant ATSB report on a practice engine failure in a Beech 1900.
https://www.atsb.gov.au/media/24342/...000492_001.pdf
I commend it to all multi-engine aircraft flying school instructors even though it deals with practice turbo-prop engine failures and not those on light piston twins typically used by flying schools.
It is probable that most flying schools engaged in initial twin engine endorsement training use a standard mantra of mixture up - pitch up- throttles up - gear up - flap up - identify failed engine by dead side dead leg - confirm with throttle - and finally feather.
All the time the simulated failed engine throttle is closed hard against the mechanical stop - or if the mixture lever was used to cut the engine - the throttles are both still forward at take off position. Either way, the propeller of the "failed" engine is windmilling and producing significant drag until the pilot gets through the engine failure mantra and finally either feathers the prop (assuming a real engine failure) or the instructor sets the throttle and pitch lever to a guesstimate of zero thrust.
With a windmilling propeller, airspeed will decrease unless the pilot deliberately lowers the nose and loses height in order to maintain safe single engine flying speed. He will probably be criticised for deliberately losing height to maintain airspeed especially if he is under the hood in simulated IMC. In other words he can't win
It could be upwards of 15 seconds going through the engine failure mantra until he gets around to "feather." All the while the "failed" engine is producing lots of drag. See the ATSB report. It may not be as severe as in a turbo-prop simulated failure but nevertheless it is bad enough to cause rapid speed loss. All this below 500 feet means the risk of loss of directional control is substantially increased as long as the prop windmills.
To mitigate (don't you just love that buzz-word) that risk or manage that "threat" as in Threat and Error Management (love that buzz-word too), CASA note
perhaps it would be safer, if instead of closing the throttle against the stops to simulate engine failure, the instructor would reduce the throttle to the approximate zero thrust position on the quadrant and announce "simulated engine failure."
There is no need to increase the risk of mishandling by allowing the huge drag from a windmilling propeller to ruin your whole day while you get around to muttering the mantra and eventually get around to setting zero thrust.
There must be a limit to faking realism in asymmetric training. The current acceptance of reducing airspeed causing increased yaw and drag associated with failure to set the throttle to zero thrust to simulate engine failure, needs to be reviewed.
I assumed that this was a C441 Conquest II. In which case it has Garrett engines (Honeywell). Those engines are not your common Pratts and must be handled in the way the manufacturer states. You can get into pretty bad trouble if you don't understand them.
For example closing the throttle to simulate an engine failure can cause the prop to go flat and especially at approach speed can result in an immediate roll and loss of control. Even after takeoff closing the throttle can do the same thing thus when practicing engine failures the IP MUST know what to do and how to do it.
If there is a genuine engine failure after takeoff the pilot must immediately move BOTH throttles to max. This will give full power on the live engine (the fuel computer should prevent an overtorque) and assist the NTS (Negative Torque System) by giving Beta Followup to move the failed engine prop toward feather (it will not actually feather the prop but will give a much reduced drag effect and buy the pilot time). Closing the failed engine throttle will put the prop into flat pitch and most likely will reduce the life expectancy of all on board to a few seconds. So you DO NOT close the throttle, not then and not later in order to confirm the failed side. Confirmation is best done using the engine gauges, the throttle should be left fully open.
In training, the IP would pull the throttle to about 300 torque (not lower) to simulate an engine failure with NTS/Beta Followup working. The student should state that the failed engine throttle is to be pushed forward, without actually doing so. During flight back to landing, the IP must guard the torque and not let it drift too low or else the prop will go flat and the airplane will not fly that way. At least not far. It is OK of course to close both throttles for the landing.
During type training I turn off the fuel using the electric fuel cutoff at a safe height and in takeoff configuration so that the student can practice the procedure. Using a Pratt procedure or a piston engine procedure will kill you. When the condition lever is pulled back the prop will feather and Bob's Your Uncle. There is a prohibited rpm range to watch out for so flying with the NTS system doing it's magic is fun but limited in time.
The airplane has excellent single engine performance, even at high weights, but the system must be understood and operated accordingly. If so it is a pussycat but it does not accept ignorance.
In the right seat for example I cannot see the STOP buttons and make sure to brief their use during training lest we suddenly be in glider reversion mode.
Another thing I see is that most pilots are not prepared to use enough rudder to maintain directional control. The airplane was certified with -8 engines and if you have the -10s the hp is way higher and I personally think the Vmca should be higher although I have no trouble with it because I am ready. It won't climb at Vmca anyway.