Simulated engine failure after take off in light piston engine twins
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Reading excellent CASA Publication CAAP 5.23-1 (2) which covers multi engine training aircraft below 5700kgs.
Interestingly there is no apparent specific mention of training for engine failure during the take off roll although it is a syllabus requirement.
A recent incident at Moorabbin was discussed at a briefing. During a training flight in a light training twin the instructor cut the mixture lever at 60 knots to simulate a rejected take off due engine failure. The new student undergoing ME training immediately lost directional control caused by his delay in closing both throttles. With full power still on the live engine the aircraft veered sharply before the instructor was able to take control before the aircraft went off the side of the runway.
The student admitted he was surprised at the instructor's actions in cutting the mixture at relatively high speed shortly before anticipated lift off and was quite unprepared for the significant swing that occurred. He thought the landing gear noise of squealing tyres and near ground loop and heavy sideways strain on the landing gear would necessitate a maintenance inspection but was over-ruled by the instructor.
A simulated engine failure during a take off roll in a light twin requires instant corrective action which must be 100% right first time. Students cannot be guaranteed to get things perfect at first attempt and this type of practice emergency stop during a take off roll is a dangerous tactic. Why do some flying instructors stick their neck out as well as their student's with such manoeuvres. Answer? Sheer overconfidence coupled with bad airmanship. Where is the threat and error mitigation here? Answer NONE. CFI's please note.
Interestingly there is no apparent specific mention of training for engine failure during the take off roll although it is a syllabus requirement.
A recent incident at Moorabbin was discussed at a briefing. During a training flight in a light training twin the instructor cut the mixture lever at 60 knots to simulate a rejected take off due engine failure. The new student undergoing ME training immediately lost directional control caused by his delay in closing both throttles. With full power still on the live engine the aircraft veered sharply before the instructor was able to take control before the aircraft went off the side of the runway.
The student admitted he was surprised at the instructor's actions in cutting the mixture at relatively high speed shortly before anticipated lift off and was quite unprepared for the significant swing that occurred. He thought the landing gear noise of squealing tyres and near ground loop and heavy sideways strain on the landing gear would necessitate a maintenance inspection but was over-ruled by the instructor.
A simulated engine failure during a take off roll in a light twin requires instant corrective action which must be 100% right first time. Students cannot be guaranteed to get things perfect at first attempt and this type of practice emergency stop during a take off roll is a dangerous tactic. Why do some flying instructors stick their neck out as well as their student's with such manoeuvres. Answer? Sheer overconfidence coupled with bad airmanship. Where is the threat and error mitigation here? Answer NONE. CFI's please note.
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The limited twin training I've done was in a PA30.
One of the exercises was to practice an approach from about 3500', dirty. Airfield elevation was assumed to be 3000'. At 3300' the instructor commanded an overshoot, and failed the right engine. I responded promptly with the required rudder, and lowered the nose to maintain the blueline. I remember being surprised at how aggressively and how much I had to lower the nose, and we only just maintained the required speed. It took me maybe 10 seconds to identify and feather the powerplant, and to raise flaps to takeoff setting, then we started a leisurely climb. From 2800'.
The instructor told me that sort of height loss at the weight we were was fairly representative, and you'd be doing extremely well to only lose 300'.
Lose an engine below about 500-1000 on departure on the average, fairly underpowered training twin, you're basically going to look for the best place to put it down, more or less straight ahead.
There is no need to do such training so low. The demo I experienced was quite graphic.
One of the exercises was to practice an approach from about 3500', dirty. Airfield elevation was assumed to be 3000'. At 3300' the instructor commanded an overshoot, and failed the right engine. I responded promptly with the required rudder, and lowered the nose to maintain the blueline. I remember being surprised at how aggressively and how much I had to lower the nose, and we only just maintained the required speed. It took me maybe 10 seconds to identify and feather the powerplant, and to raise flaps to takeoff setting, then we started a leisurely climb. From 2800'.
The instructor told me that sort of height loss at the weight we were was fairly representative, and you'd be doing extremely well to only lose 300'.
Lose an engine below about 500-1000 on departure on the average, fairly underpowered training twin, you're basically going to look for the best place to put it down, more or less straight ahead.
There is no need to do such training so low. The demo I experienced was quite graphic.
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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.
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.
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.
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It is not often that I am in complete agreement with Leadsled re Part 23 twin training.
On C441 in particular and Garretts in general, boofhead goes to the top of the class.
On C441 in particular and Garretts in general, boofhead goes to the top of the class.
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Most multi engine instructors require their students to not only identify which is engine has failed following a simulated engine failure, but to confirm by pulling back the throttle of the "failed" engine despite that throttle has already been pulled back to simulate the engine failure. So already we have a recipe for confusion. Next problem is regarding a real engine failure procedure once again taught by flying schools. Identification is by `dead side dead leg` a method tried and trusted throughout the years. But then students are taught to close the dead engine throttle to confirm you have the real dead engine.
But hang on a second. Apart from only one aircraft POH (and I think it may be a Beech Baron) I have yet to see published in any manufacturer's AFM or POH that confirmation by pulling back the dead engine throttle is required. In fact, confirmation you have the correct dead engine by throttle pull back, was only applicable to a four-engine aircraft. Dead side dead leg still applied; but which of the two engines on that side was the crook donk? After all there is a swing towards that side.
Now this is where the confirm with throttle gentle closure came in. If you pull back the wrong dead engine throttle the yaw will increase significantly whether you are flying a DC4, a Lancaster bomber or a Super Constellation. That is the real story behind "confirm with throttle closure." It was never meant to apply to a twin engine aircraft in my time and that goes back a few years.
With the proliferation of turbo-prop aircraft on the Australian register, where some have auto-coarsen or autofeather, a pilot instinctively reverting to his flying school teaching of throttle closure to confirm would likely immediately find himself in serious handling trouble of his own making. That is because of excessive drag, since throttle closure would negate the auto-coarsen and auto-feather system. Thus leaving the aircraft with potentially disastrous drag on one side. This is one possibility for the investigators of the C441 Renmark accident to consider.
What is currently taught during initial twin training at a flying school in terms of practice engine failures at low altitude, may be quite different when applied to a twin turbo prop. This is especially relevant if the instructor has never flown a twin turbo-prop which probably applies to a high percentage of ME instructors.
In short, there is no need to double confirm which engine has failed following an engine failure of a twin engine aircraft. The instant yaw towards the dead engine is confirmation enough. This is especially on take off where the time taken going through the lengthy list of drills as taught at flying schools, before the pilot finally gets to feather the dead engine prop, means drag from its windmilling propeller can lead to drastic airspeed loss.
But hang on a second. Apart from only one aircraft POH (and I think it may be a Beech Baron) I have yet to see published in any manufacturer's AFM or POH that confirmation by pulling back the dead engine throttle is required. In fact, confirmation you have the correct dead engine by throttle pull back, was only applicable to a four-engine aircraft. Dead side dead leg still applied; but which of the two engines on that side was the crook donk? After all there is a swing towards that side.
Now this is where the confirm with throttle gentle closure came in. If you pull back the wrong dead engine throttle the yaw will increase significantly whether you are flying a DC4, a Lancaster bomber or a Super Constellation. That is the real story behind "confirm with throttle closure." It was never meant to apply to a twin engine aircraft in my time and that goes back a few years.
With the proliferation of turbo-prop aircraft on the Australian register, where some have auto-coarsen or autofeather, a pilot instinctively reverting to his flying school teaching of throttle closure to confirm would likely immediately find himself in serious handling trouble of his own making. That is because of excessive drag, since throttle closure would negate the auto-coarsen and auto-feather system. Thus leaving the aircraft with potentially disastrous drag on one side. This is one possibility for the investigators of the C441 Renmark accident to consider.
What is currently taught during initial twin training at a flying school in terms of practice engine failures at low altitude, may be quite different when applied to a twin turbo prop. This is especially relevant if the instructor has never flown a twin turbo-prop which probably applies to a high percentage of ME instructors.
In short, there is no need to double confirm which engine has failed following an engine failure of a twin engine aircraft. The instant yaw towards the dead engine is confirmation enough. This is especially on take off where the time taken going through the lengthy list of drills as taught at flying schools, before the pilot finally gets to feather the dead engine prop, means drag from its windmilling propeller can lead to drastic airspeed loss.
A37575, I would suggest that failing to confirm (but not necessarily by retarding the throttle) after deciding dead leg = dead engine, is not a good practice. A common trope with PT6 powered twins eg Kingairs, is 'dead leg = dead engine = dead pilot'.
PT6s have a single point failure in their fuel pump governor that will give an extreme runaway engine, with similar yaw characteristics to a failed engine. The difference is that the yaw is *towards* the GOOD engine. If you don't confirm the runaway (from torque, temp, & Ng gauges in this case) then you could feather & shutdown the *normally* functioning engine, with the remaining engine about to disintegrate.
Bear in mind that in this situation autofeather *will not* engage. You're left with an uncommanded yaw towards a properly functioning engine. Those dead foot = dead engine drills will kill you.
PT6s have a single point failure in their fuel pump governor that will give an extreme runaway engine, with similar yaw characteristics to a failed engine. The difference is that the yaw is *towards* the GOOD engine. If you don't confirm the runaway (from torque, temp, & Ng gauges in this case) then you could feather & shutdown the *normally* functioning engine, with the remaining engine about to disintegrate.
Bear in mind that in this situation autofeather *will not* engage. You're left with an uncommanded yaw towards a properly functioning engine. Those dead foot = dead engine drills will kill you.
And the critical part of "retarding" the throttle is not to remove power from that engine as much as seeing if it is responsive, which in no way requires retarding it to idle.
I agree with Old Akro and Tinstaafl regarding confirmation. Even by using the throttle on a piston twin to confirm I also teach to check fuel flows and EGT.
There is another very good reason for closing the throttle on a piston twin and probably other types as well. Unless you are terrain critical you will be doing some trouble shooting. Having an engine come back to life with a cruise throttle setting is most likely going to result in a rather large engine/prop overspeed which will mean expensive teardowns for the engine and prop. There will be a significant yaw as well.
There is another very good reason for closing the throttle on a piston twin and probably other types as well. Unless you are terrain critical you will be doing some trouble shooting. Having an engine come back to life with a cruise throttle setting is most likely going to result in a rather large engine/prop overspeed which will mean expensive teardowns for the engine and prop. There will be a significant yaw as well.
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Confirming by closing the throttle of the suspected failed engine is the generally accepted best practice by some instructors. Others do not accept this premise for sound reasons. It could have the unintended consequences of double engine loss of power if during the identification, the pilot in fact closes the wrong side throttle in his efforts to confirm which engine is dead. No problem if that happens at cruise altitude but awfully embarrassing if shortly after lift off.
If the engine failure was due to a severe internal mechanical failure resulting in a rapid loss of RPM, and thus inability to feather below a certain RPM, any delay in feathering (caused by slowly closing the throttle to confirm the power loss) could be disastrous.
If the engine failure was due to a severe internal mechanical failure resulting in a rapid loss of RPM, and thus inability to feather below a certain RPM, any delay in feathering (caused by slowly closing the throttle to confirm the power loss) could be disastrous.
There appears to be an overlap between piston engines and turbines in the discussion.
I would like to explore the history of a pilot. When we start out, all our training is in pistons and outside of an airline environment most of our practiced EFATO exercises are in pistons and there’s nothing fundamentally wrong with any of the techniques discussed here, but there are some traps. When we move on to our first turbine. Most likely it will be a free power turbine and there are differences. Just to illustrate this I will extract a tiny piece of discussion for the purpose “I also teach to check fuel flows and EGT.” in a free power turbine you can have a failure (loss of the all important torque) and the engine is still running normally (ITT/fuel flow) which can send you down the wrong path. Then when we migrate to a fixed shaft turbine like the garrett, a completely different beast again.
There’s no one size fits all, how do we deliver effective differences training in a way that if missed or slips through the cracks the pilot doesn’t lapse back into what he knows or what he’s used to previously.
I know I havn’t explained this very well. How does one execute something he does not know.
I would like to explore the history of a pilot. When we start out, all our training is in pistons and outside of an airline environment most of our practiced EFATO exercises are in pistons and there’s nothing fundamentally wrong with any of the techniques discussed here, but there are some traps. When we move on to our first turbine. Most likely it will be a free power turbine and there are differences. Just to illustrate this I will extract a tiny piece of discussion for the purpose “I also teach to check fuel flows and EGT.” in a free power turbine you can have a failure (loss of the all important torque) and the engine is still running normally (ITT/fuel flow) which can send you down the wrong path. Then when we migrate to a fixed shaft turbine like the garrett, a completely different beast again.
There’s no one size fits all, how do we deliver effective differences training in a way that if missed or slips through the cracks the pilot doesn’t lapse back into what he knows or what he’s used to previously.
I know I havn’t explained this very well. How does one execute something he does not know.
Confirming by closing the throttle of the suspected failed engine is the generally accepted best practice by some instructors. Others do not accept this premise for sound reasons. It could have the unintended consequences of double engine loss of power if during the identification, the pilot in fact closes the wrong side throttle in his efforts to confirm which engine is dead.
Also if the wrong throttle is pulled back it won't require being moved anywhere close to closed before it is obvious the wrong lever has been used.
No problem if that happens at cruise altitude but awfully embarrassing if shortly after lift off.
If the engine failure was due to a severe internal mechanical failure resulting in a rapid loss of RPM, and thus inability to feather below a certain RPM, any delay in feathering (caused by slowly closing the throttle to confirm the power loss) could be disastrous.
If the engine failure was due to a severe internal mechanical failure resulting in a rapid loss of RPM, and thus inability to feather below a certain RPM, any delay in feathering (caused by slowly closing the throttle to confirm the power loss) could be disastrous.
As has been mentioned by others there is no one size fits all. Teaching one method just because that method may be better for another aircraft that may be flown in the future is misguided. The tuition needs to match the aircraft being flown.
in a free power turbine you can have a failure (loss of the all important torque) and the engine is still running normally (ITT/fuel flow) which can send you down the wrong path
The ITT/fuel flow will still be commensurate with the degree of loss of TQ, both low.
Not at all, In the case of a second stage power turbine partial failure {burnt) (The turbine that extracts the energy to drive the gearbox) ITT and Fuel Flow may even be higher as the gas section tries to spool up to restore the torque.
Not at all, In the case of a second stage power turbine partial failure {burnt) (The turbine that extracts the energy to drive the gearbox) ITT and Fuel Flow may even be higher as the gas section tries to spool up to restore the torque.
Maybe we should go a bit further with this, you are lined up for takeoff and push the power levers up when one of the engines hits an ITT limit well before takeoff torque is achieved, so you abort the takeoff.
Tell me what the two most likely causes are (whats wrong with the engine)
Tell me what the two most likely causes are (whats wrong with the engine)
In the case of a second stage power turbine partial failure {burnt)
one of the engines hits an ITT limit well before takeoff torque is achieved
HP = Torque x RPM, not much energy required to produce the RPM but lots of energy required to produce Torque, if you don't have the Torque you don't have the HP, if in doubt get rid of it. we are trained to fly on one engine and two engines, not one and a half engines. An engine without the torque is likely to be producing more drag than thrust and a really dangerous place to be.