Simulated engine failure after take off in light piston engine twins

[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/aair200000492_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 :ugh:

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 :ok: 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.

[Band a Lot]

I think the ultimate problem will be - way too much experience in the pilots on board.

The seen boss will be the CASA person by crew - They do bash that big stick often.


Then the 2 crew, both with big experience.


Who will say what when wen it is not as planned?


To many chiefs on this brief is possible!

[CAVOK92]

It would be a lot safer for the instructor to call out "engine failure right engine" with no engine input.

Multi engine instruction has its risks. All flight training has risk involved. It is up to the instructor to step in before the aircraft and crew are positioned in a un safe situation.

There is a reason you need to do a multi engine training approval before you go simulating failures.

There is a reason you need to see exactly how the aircraft with perform when an engine fails.

There is a reason you need to feather the propeller when the engine failes. There is a big handeling and performance difference which the candidate needs to see and practice.

There has been a couple of threads recently that have made me start to worry about the current quality of multi engine instructors. It makes me sick thinking about the poor kid that is going to kill himself and his family when an engine stops all because he never received adequate assymetric training.


ME turbines are a diferent beast and need to be treated with even more respect. There is a reason they make you do the training in a simulator if one is available.

[drpixie]

It could be upwards of 15 seconds going through the engine failure mantra until he gets around to "feather."

Sorry but if you're taking 15 seconds to get through the mechanical drill, I would have said something like "you've got the idea but you've got to be up to standard ... I think you need another session of assy circuits." I would not put someone up for a rating test at that standard.

The whole point of this training is to know what really happens (close throttle is a clean best-case engine failure, plenty are more confusing). And to handle it in sensible fashion. Both of these need as realistic practice as can be done safely. When it really happens, you will go into pause mode - minimum pause is good :)

[megan]

An unfortunate statistic.6.3.2 ATSB statistics indicate that 16% of multi-engine aeroplane accidents occur during training or assessment. Unfortunately, a number of these accidents were caused by unsatisfactory behaviour by instructors or ATOs.https://www.casa.gov.au/file/104981/download?token=HK_Z2wzP

Practising bleeding leads to the real thing on occasions. Vale Les Morris.

[Xeptu]

well I'll say it, drpixie, how does one feather a piston engine prop in much less than 15 seconds

[27/09]

While engines can and do happen at any point of a flight profile, there is absolutely no need to simulate engine failures at critical phases of flight where, if the exercise is not properly handled, will likely result in the loss of the aircraft and occupants.

Remember we are either training to do the engine failure properly or checking to see the candidate can do it properly. This can be achieved at heights that allow room for recovery if there is a stuff up.

[Tarq57]

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.

[drpixie]

well I'll say it, drpixie, how does one feather a piston engine prop in much less than 15 seconds

Note that you're expecting the "failure" (and you'll see your instructor's hand reaching for the mixture) so there should be no "surprise" time (unlike real life):
- you keep the aircraft straight with normal controls (primarily rudder) and notice the failure - 1 second
- mix, pitch, power UP - one hand, one second
- identify "dead leg" - one second
- confirm by closing throttle - one second
- identify and pull the pitch to feather - one second
- then check gear & flaps & blue line
with minor variations in order depending on the aircraft (check your POH & SOPs).

That makes it about five seconds - I wouldn't care if it takes a little longer as long as the aircraft is flown for good performance (blue line), no significant loss of altitude, and you don't take the wrong engine!

For average small & medium twins, you should be able to do that quite mechanically and without loosing any altitude. If you are loosing altitude, or getting below blue line, then I don't want my family in the aircraft with you - because real engine failures do happen.

And Tarq57, Lose an engine below about 500-1000... I absolutely agree - got to be familiar with your aircraft and should have a "committed" height nominated - below that, you're going to land somewhere.

Too all up-and-coming multi-engine pilots - you're moving into a more serious regime - bigger, faster, more powerful aircraft with more pax. You've got to learn from other people mistakes because sometimes you'll only get one chance. So be very familiar with some kind of take-off briefing, Vmc, sensible initial climb attitude & speed, after T/O decision point, before landing committed point, actions to perform on engine failure before & after decision point. There are a couple of quite good multi-engine books, available at more pilot shops. If your instructor doesn't know & stress these things, find another one.

[jas24zzk]

Committed height is bollocks. (more on that)

15 seconds to go through the mantra...about right, including stabilising. Should be doable quicker at test stage.

The reason i call bollocks on committed height comes from my limited knowledge of what is taught in BPPP.
Their training on barons, is that if the flaps and wheels are not up, then it it close both throttles and land ahead. Treat the aeroplane as a single.

As for an instructor doing the simulation by a mixture cut...that will be the end of the flight for me. Its a training flight! Throttle cut, that way if i get it wrong, then either of us can bring the throttle up again. Sure still not instantaneous, but a dammed sight quicker if you are 3/4 through the drill and need power.

As for zero thrust, we all rely on our instructors to know those numbers. Mine made me learn them and correct him where required. he probably didn't need me to tell him, but me knowing them also gave a safety scope in that I knew what was needed and if outside of it i could call a halt to the exercise.

[sheppey]

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.

[Centaurus]

Practising bleeding leads to the real thing on occasions. Vale Les Morris.

megan is offline Report Post
Megan. Check your PM's

[prospector]

.


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.

That is why the instructor who is carrying out the exercise, who knows what he, or she, is going to do, should be ready to immediately rectify the situation if the student does not get it right.

[CAVOK92]

Sounds like the instructor wasn't doing his job properly to me. No practiced engine failure on takeoff roll should result In a runway excursion. It is the instructors responsibility to rectifie the situation before it results In loss of directional control.

"Student was surprised [by how the aircraft handled]". That why there is a reason it should be precticed with the proper safety measures in place.
- ghost the rudder to prevent the opposite input.
- have your hand on the other mixture should the student not have a satasfactory response.
- If your going to stuprise the student, don't do it at 60kts.

Assymetric operation can be safely practiced however it requires the person in the right hand seat to be diligent and considerate of the possible threats and errors that could be experienced.

[megan]

No PM received Centaurus.

[drpixie]

Committed height is bollocks ... is that if the flaps and wheels are not up, then it it close both throttles and land ahead.

So they have a committed config instead of a committed height :ugh: but same idea, after some defined point in the approach, you will not be able to go around on one engine.

[Centaurus]

Megan. Finger trouble on my part.:E Try your PM's again

[27/09]

Committed height is bollocks. (more on that)

15 seconds to go through the mantra...about right, including stabilising. Should be doable quicker at test stage.

The reason i call bollocks on committed height comes from my limited knowledge of what is taught in BPPP.
Their training on barons, is that if the flaps and wheels are not up, then it it close both throttles and land ahead. Treat the aeroplane as a single.

As for an instructor doing the simulation by a mixture cut...that will be the end of the flight for me. Its a training flight! Throttle cut, that way if i get it wrong, then either of us can bring the throttle up again. Sure still not instantaneous, but a dammed sight quicker if you are 3/4 through the drill and need power.



Do you mean committal height? If so then I have to disagree. Asymmetric committal height is something all light twin drivers should think about for every landing. Below that height you're committed to land as a single engine go around will most likely result in a touch down anyway.

I've never heard of a commit height for departure. Blue line achieved and gear up are the milestones for departure.

Simulating engine failures by closing the throttle isn't the best method in my opinion.

A mixture cut is kinder in the engine pistons and rings and gives indications that more closely resemble a real engine failure in a normally aspirated aircraft. In other words the manifold pressure and RPM indications mimic a real engine failure.

Closing the throttle gives a false manifold pressure indication and the throttle lever is in the wrong place for the drills that need to take place.

I've never had an issue bringing the power up from mixture cut.

[jas24zzk]

Sorry Drpixie, missed the clarification in your response to tarq57. He specifically mentions departure, whilst you mention approach.

Cheers

[Creampuff]

A mixture cut <snip> gives indications that more closely resemble a real engine failure in a normally aspirated aircraft. In other words the manifold pressure and RPM indications mimic a real engine failure.

Closing the throttle gives a false manifold pressure indication and the throttle lever is in the wrong place for the drills that need to take place.

I've never had an issue bringing the power up from mixture cut.Correct and unsurprising, although in some cases the resumption of power may depend on the specific fuel system fitted to the particular engine and aircraft.

But I have the popcorn ready for this one:A mixture cut is kinder in the engine pistons and rings ...Pray tell us your theories around this assertion.

[CAVOK92]

Simulating engine failures by closing the throttle isn't the best method in my opinion.

A mixture cut is kinder in the engine pistons and rings and gives indications that more closely resemble a real engine failure in a normally aspirated aircraft. In other words the manifold pressure and RPM indications mimic a real engine failure.

Closing the throttle gives a false manifold pressure indication and the throttle lever is in the wrong place for the drills that need to take place.

I've never had an issue bringing the power up from mixture cut.

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.

We have all heard the stories of pleople shutting down the wrong engine.

I have had many students identifie the wrong engine. Glad they did it with me, not when it's the real deal.

[CAVOK92]

A good article on engine failures.
Sample Chapter - Flying Wisdom, Proficient Pilot 3 by Barry Schiff (http://www.barryschiff.com/sam_pp3.htm)

[Centaurus]

I usually make it a practice to hide the mixture controls from the student with a large piece of cardboard or a manila folder. In this way, he cannot determine which engine has failed by glancing at the mixture-control levers. This technique gives the student access to the throttles and propeller-pitch controls, and he is forced to go through the procedures just as if the engine had genuinely failed.


Quote is from Schiff link. Evidence from surviving pilot revealed the instructor used this technique in the Camden Duchess fatal accident a few years back. Except he couldn't get the dead engine back to life fast enough before clipping trees and stalling into the ground.

[LeadSled]

Pray tell us your theories around this assertion.

Creamie,
I always love this one, it immediately reveals a certain gap in the knowledge of what happens inside an engine.
Tootle pip!!

[27/09]

Quote is from Schiff link. Evidence from surviving pilot revealed the instructor used this technique in the Camden Duchess fatal accident a few years back. Except he couldn't get the dead engine back to life fast enough before clipping trees and stalling into the ground.

I'd suggest the problem wasn't so much the technique but more where or at what height the simulated failure was initiated or how far the instructor let things develop before intervening.

[Biggles78]

I was taught, dead leg, dead engine and to TOUCH the dead leg to confirm you were securing the correct powerplant. I never looked at the throttles or mixtures to identify which side was failed as it was a waste of time since it wouldn't help during an actual failure and IMO took away from the training.


Is the touch the dead leg not taught anymore?

[XP-72]

Old Phil Zupp made me slap the dead leg hard - not 'touch' it
- certainly made you aware

[Old Akro]

I don't know the people involved or the detail of the accident. But there is a pretty long history of accidents with CASA pilots on board. I think the earlier poster who raised questions about the cockpit dynamics with someone on board who has the unchallengeable power of a CASA person deserves reflection more than trading opinions on asymmetric training techniques.

[megan]

questions about the cockpit dynamics with someone on board who has the unchallengeable power of a CASA person deserves reflectionThere is a story in the community about a CASA officer wanting to see a stall in a Metro, as it was a box he had to tick on checking the pilot. Wanted the pilot to disable the stall protection in order to achieve stall. Unable to find report on ATSB, but told it was at Lake George.

[LeadSled]

Megan,
Not a story, but a fact, said FOI wanted the SATS c/b puller. The head of training refused, which had calamitous consequences for his career. It was Avtex Aviation at YSBK. There were some "interesting" discussions about "the law" versus AFM limitation.
"We" finally had the Type Certificate holder in US write a letter saying that such a manoeuver was absolutely prohibited, except in test conditions, with a spin recovery parachute fitted.
As fate would have it, due to an inadvertently not reset SATS c/b, a Norwegian Metro was lost on a training flight in a deep stall ---- a hard way to prove the point.
I my opinion, to this day, it is unlikely that the FOI involved understands deep stalls in a T-tail aircraft.
Tootle pip!!

[gerry111]

Avtex Aviation at YSBK.


Avtex Air Services Pty Ltd trading as Airtex Aviation.

[Centaurus]

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”.
............................................................ ..............................

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”.
............................................................ ....................................
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:ok:

[LeadSled]

Centaurus,
Thanks for that, and NOT an eyeopener to those of us who have been around quite a while. I hope some (all??) will read, and learn.

Sadly, I think you are of the belief that facts have any "impact" on prejudices. Never let the facts spoil a good story.

Just look at many of the posts on this thread, the naive but firmly held belief that what "they" are doing is not just OK, but necessary for asymmetric training, and they are so competent and mistake-proof, that they can "safely" defy the odds.

As ever, a significant proportion of Australia's aviation community does not even really accept the concepts of genuine formal risk assessment, and mitigation. That is, "they" do not accept rational risk management, "they" are so "competent", in their own eyes, that risk mitigation is entirely irrelevant.

Another example is the generally irrational negative attitude to ICAO airspace classification, firmly grounded on risk assessment and mitigation, in favour of "that the way we do it in Australia", from too large a proportion of the Australian aviation community.

Tootle pip!!

[ForkTailedDrKiller]

I have been sitting in the wings quietly reading this thread. I have nothing to offer in the way of expertise in this area other than having trained on many of the common avgas powered light twins (PA23, PA30, PA31, BE76, Baron, C310, C402 - I have no turbine time) and undertaken many IR renewals in same.

I have only flown these activities with very experienced and highly regarded instructors.

I cannot recall an engine failure on take off having ever been simulated other than by using the mixture control! :confused:

Dr :8

[IFEZ]

I'm with you Dr. I must say I'm a bit perplexed by all this. I'm no expert on the matter and I'm certainly not trying to contradict others on here who clearly have vastly more experience and expertise than me, but when I did my initial twin training and further training on other types, like the good Dr, simulated engine failures were always done using the mixture control. As far as I'm aware, all the schools at MB were using this method, and presumably still are. (And at low level too ie in the circuit).


My question is, if this method is so inherently dangerous, and given the amount of twin training that happens at MB and elsewhere, why haven't there been more accidents of this type during training and proficiency checks..? Have we all just been incredibly lucky..?! http://cdn.pprune.org/images/smilies/confused.gif

[KRviator]

My question is, if this method is so inherently dangerous, and given the amount of twin training that happens at MB and elsewhere, why haven't there been more accidents of this type during training and proficiency checks..? Have we all just been incredibly lucky..?! http://cdn.pprune.org/images/smilies/confused.gifPut the shoe on the other foot.

How many accidents have occurred as a result of an actual engine failure on takeoff in a piston twin? Less than those caused by training for an engine failure on takeoff, I'll bet!

[IFEZ]

Hmmm, I see your point..!

[Centaurus]

For those that still have their doubts about their own mixture cuts during their training, it is worthwhile reading this CASA CAAP. Part of it is reproduced below. Notwithstanding all the official evidence of the folly of playing around with mixture cuts as part of take off asymmetric "training," there is anecdotal evidence this practice is still happily used at some Australian flying schools. The advice contained in the CAAP is thus disregarded under the old chestnut of "but I've always done it and had no problems, so why should I change?"

why haven't there been more accidents of this type during training and proficiency checks..?

The mishandling and close shaves invariably associated with mixture cuts at low altitude in all probability never get reported by instructors..
............................................................ ..........................................

September 2015
CAAP 5.23-1(2)
Multi-engine aeroplane operations and training
This CAAP will be of interest to:
 multi-engine aeroplane pilots
 flight instructors
 approved testing officers (ATO)
 flying training providers.
Why this publication was written
Following a number of multi-engine aeroplane accidents caused by aircraft systems mismanagement and loss of control by pilots, flight instructors and persons approved to conduct multi-engine training, this CAAP was written to address threats and errors associated with multi-engine operations and provide advice on multi-engine training. This CAAP also includes competency standards for multi-engine operations, suggested multi-engine and flight instructor training syllabi and a questionnaire to assist pilots to learn and assess their aircraft systems knowledge.
Status of this CAAP
This is the third CAAP to be written on this subject. This CAAP will be superseded with a Part 61 Advisory Circular (AC) in the future.
For further information
Telephone Flight Standards Branch on 131 757.
Civil Aviation Advisory
Publication
September 2015...................
............................................................ ......................

The relevant paragraph dealing with practice engine failures states:
6.8 About engine failures
6.8.1 Flight instructors often simulate an engine failure by rapidly closing the throttle or moving the mixture control to idle cut-off. The latter method should never be used at low altitude

According to the earlier quoted NTSB report published in Key Reprints from Lycoming Flyer, throttle closure should be done slowly to prevent engine failure or damage.

[27/09]

I'm with you Dr. I must say I'm a bit perplexed by all this. I'm no expert on the matter and I'm certainly not trying to contradict others on here who clearly have vastly more experience and expertise than me, but when I did my initial twin training and further training on other types, like the good Dr, simulated engine failures were always done using the mixture control. As far as I'm aware, all the schools at MB were using this method, and presumably still are. (And at low level too ie in the circuit).


My question is, if this method is so inherently dangerous, and given the amount of twin training that happens at MB and elsewhere, why haven't there been more accidents of this type during training and proficiency checks..? Have we all just been incredibly lucky..?! http://cdn.pprune.org/images/smilies/confused.gif

No I don't think so.

I'm at a loss to understand exactly why the throttle is being promoted as a safer way to simulated an engine failure. The only explanation offered is the engine responds more reliably. I've never had an issue with using the mixture.

It's my hypothesis that a significant proportion of training accidents are caused by either the instructor trying to be too "realistic" and/or simulating at inappropriate altitudes or in inappropriate conditions. If the difference in safety is a matter of whether or not the mixture or throttle is used then I'd venture to suggest the timing of the simulation was inappropriate.

[A37575]

I'm at a loss to understand exactly why the throttle is being promoted as a safer way to simulated an engine failure

Surely that should be obvious? You have instant power available should the circumstances require it. With a mixture cut you have failed the engine and instant power is not available if the student stuffs up. To re-start the engine after a mixture cut the instructor first has to close the throttle of that engine. Secondly he has to advance the mixture to open. Thirdly he has to restore power by re-opening the throttle either to zero thrust to simulate feathering the prop or to restore to climb power if the exercise is completed.
Another factor is the type of engine. If fuel injected and the mixture is cut there is a possibility that depending for how long the mixture has been cut, fuel in the injector lines may not be instantly available and you are left stranded with not only a windmilling prop (big drag) but no power until the fuel is running again. All the time the student could be getting out of his depth while you are sorting out the fuel problem and leaving him to it.

At Tyabb this is exactly what happened some years ago and the aircraft crashed and caught fire. The instructor cut the mixture lever while joining the circuit and the student was required to fly the circuit with a windmilling prop - not a zero thrust prop. To add insult to injury the instructor told the student it would be a touch and go as he would start the engine just before touch down. The student opened up both throttles after touch down to do the touch and go. Unfortunately the "failed" engine failed to deliver power due to fuel in the injector lines having been diminished. The student lost directional control, the instructor now with his hands full took over control, but departed the airstrip and hit a log of wood. The aircraft caught fire causing minor burns to the two pilots. A simple throttle closure to simulate engine failure would have been a safer option but the instructor wanted to give the student the practice of flying a circuit with a windmilling prop on a real dead engine. Not an example of good airmanship in anyone's language

[Creampuff]

I used to be alarmed at the level of ignorance manifested by these mixture v throttle cut simulated engine failure threads. These days I'm just sad.

Sad because I've come to the conclusion that the level of stupid-proofing of most piston engined aircraft fuel systems will always be what it is, the level of ignorance in the pilot/instructor population will continue to be whatever it will be, and therefore the rate of training-induced accidents will continue to be whatever it is.

It's as if no one has ever looked under the cowls and studied the fuel systems of various aircraft and noticed that not all fuel systems are the same.

Sad. :(

[27/09]

A37575

Two points from your post.

The accident you quote in your post is a prime example of what I was talking about, - Inappropriate simulations. A touch and go in this scenario is always risky no matter the engine failure method, see my comment below. In my view the prime cause was the decision to carry out the touch and go without first knowing the engine would respond properly.

Secondly, seriously how long does it take to restore power after a mixture cut. You make it seem like it's a drawn out process. It's not. If there's not sufficient time then the timing of the simulation is inappropriate no matter the method you use.

One last point, everyone seems to be forgetting the incidents and accidents that have occurred when the engine has failed to respond on a PFLWOP that has been initiated by closing the throttle.

[sheppey]

One last point, everyone seems to be forgetting the incidents and accidents that have occurred when the engine has failed to respond on a PFLWOP that has been initiated by closing the throttle.

As you rightly say, there have been numerous events of the type you describe. While it is usually difficult to say for certain the reason the engine has failed to respond on practice forced landings, especially if there was no obvious mechanical failure, investigations have usually pointed out the weather conditions were conducive to carb icing; exacerbated by the pilot forgetting to use or incorrectly using, carb heat during prolonged glide at idle power. That is an entirely different subject to the discussion points on this thread

[27/09]

As you rightly say, there have been numerous events of the type you describe. While it is usually difficult to say for certain the reason the engine has failed to respond on practice forced landings, especially if there was no obvious mechanical failure, investigations have usually pointed out the weather conditions were conducive to carb icing; exacerbated by the pilot forgetting to use or incorrectly using, carb heat during prolonged glide at idle power. That is an entirely different subject to the discussion points on this thread

No doubt some of the incidents were caused by carb icing however in my experience plug fouling as a result of extended low power (idle) settings is prevalent as well.

My main point is I don't believe there is any material difference from a safety point if view between the two methods and the precursor of most single OEI training accidents is the exercise being carried out in an inappropriate manner.

[sheppey]

My main point is I don't believe there is any material difference from a safety point if view between the two methods
The manufacturer would have access to a large data base of incidents and accidents for their aircraft and from this would not have lightly published this recommendation. Nor would have the NTSB in its warning. Best of luck with your mixture cuts in future. Don't tell CASA though...


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”.
............................................................

[drpixie]

... from this would not have lightly published this recommendation. Nor would have the NTSB in its warning.

Don't underestimate the enormous amount of arse-covering that goes on in this industry. If someone in the manufacturer, FAA, CASA, etc can point to "I said that X might be a problem", then they feel safer - even though there may be good reasons to do X under some (or even many) circumstances.

The important thing is that we consider and evaluate pluses and minuses in situ ... avoiding anything potentially linked to a minus does not lead to competent pilots or good training.

[Creampuff]

The manufacturer would have access to a large data base of incidents and accidents for their aircraft and from this would not have lightly published this recommendation. Nor would have the NTSB in its warning. Best of luck with your mixture cuts in future. Don't tell CASA though...

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”.
............................................................ Again, the number of misconceptions manifested by the material in that post is saddening.

I'll bet that the 'use the throttle rather than mixture control' crowd believe that:

- Pulling the mixture completely shuts off fuel to the engine, and

- This is true for all engine/airframe combinations.

Both are demonstrably wrong generalisations. However, the demonstration requires an understanding of how the different fuel systems fitted to different engines and different aircraft behave differently. Better, instead, to stick with the blissful ignorance that pulling the throttle will always be less risky than pulling the mixture to simulate an engine failure, no matter the aircraft and no matter the engine.

The only real-life failure of a piston engine to respond after a simulated engine failure of which I am aware was simulated by pulling the throttle. An understanding of the specific fuel system and specific engine fitted to that specific aircraft made it obvious why that method of simulation was no more likely than pulling the mixture to end in a failure to respond when trying to obtain full power. (Not a carby icing problem, BTW. Injected engines don't have a carby.)

Procedures on some aircraft require an electric fuel pump to be on for e.g. Take-off. Procedures on other aircraft warn against the use of an electric fuel pump for e.g. Take-off. How could both be correct, if all fuel systems on all piston engines and all aircraft are the same?

Engine designers and manufacturers, airframe designers and manufacturers, engine maintainers, airframe maintainers, regulators, accident investigators and insurers all have a vested interest in saying that if only the pilot had done something different from what they did, the damage/accident/incident would not have occurred. The difference between correlation and causation is often (conveniently) overlooked.

[Centaurus]

From revisiting all these posts it is clear there are two camps. Ops normal in many discussions where strong opinions are aired. I have yet to see in any pertinent document produced by manufacturers or State regulatory authorities that closing the throttle to simulate an engine failure after take off is not recommended for reasons of flight safety. Perhaps the wording should be amended to Human Factors. In other words almighty cock up's by one or other of the crew.

On the other hand we have seen in these posts documentary evidence from two State regulatory authorities (CASA and UK CAA) as well as the US NTSB, that mixture cuts used to simulate engine failures after take off are not recommended for flight safety reasons (i.e. Human Factors) A further CASA flight safety document CAAP states the same thing.

Reminds me of the adage traced back to Year 1546 "There are none so blind as those who will not see.":ok:

[Creampuff]

At least for my part, I'm in neither "camp". It's a false dichotomy that is a manifestation of the problem.

I'm happy to be in a piston aircraft in which engine failures are simulated by pulling the throttle, provided that that happens to be the least risky way to simulate failures on that specific aircraft with that specific fuel system and engine.

I'm also happy to be in a piston aircraft in which engine failures are simulated by pulling the mixture, provided that that happens to be the least risky way to simulate failures on that specific aircraft with that specific fuel system and engine.

I'm never happy to be in a piston aircraft in which the instructor or ATO is chock full of one-size-fits all rules.

That even regulatory authorities can suggest that one method is generally less risky than another just demonstrates that old wives' tales, like weeds, take hold everywhere. Appeals to authority never impress me.

[Pinky the pilot]

I did the second half of my CPL and my MECIR in a Seneca 1 with an Instructor who is still well known and respected with, shall we say, `older` Pilots in the Industry.:ok:

His initials are IAK, better known as TK.

His technique for simulated engine failures were; After Take off, using the mixture, hiding the levers behind something handy. Sometimes he would hide the levers but not fail an engine, just to keep you on your toes!!:eek::hmm:

In level flight at a safe cruising altitude he would turn the fuel off! Generally when he reached for a cigarette because he kept the packet on the fuel selectors!:ooh:

I don`t know if he ever twigged but whenever I saw his hand go down to his fag packet, I knew an engine was about to `fail.`:}

I have no argument with all the simulated failures he gave me, and they were countless!:eek:

Simply because I am convinced that they more than adequately prepared me for the three genuine failures I subsequently experienced in my later flying time in PNG.:eek:

Even if they were in Bongo Vans!:yuk:

[mattyj]

Maybe for engine failures in the cruise but if you're doing mixture cuts in the circuit you should bloody well do it by yourself and not endanger your students...some people just think their lives aren't exciting enough!

[mrs nomer]

The ATO himself/herself, and not the student, has failed the test if mixture or fuel off is used to generate the failure on take-off.

Under any analysis, that's putting the aircraft at significant risk.

I don't even know why this discussion is still occurring.

[LeadSled]

Folks,
For may years, I worked with an operator with a well deserved reputation for risk minimization ( inaccurately aka "safety") and I have always been happy with their logic, and applied it to my own operations.
ALL their aircraft were certified with whatever were the DCA/CAR/FAR transport standards of the day, which all included a certified "stop/go" capability in the event of engine failure.

NOT a feature, generally, of FAR 23 aircraft.

The training rules were really quite simple:
(1) The only time you shut and engine down (by the approved method) and feathered was above 3000'minimum, 6000'+ preferred AGL, daylight, VMC.
(2) All engine failures on takeoff, and any related operation below 3000', simulate the failure by SLOWLY retarding the throttle, sufficient to ensure the student/candidate correctly identified the failed engine, and then manipulating the manifold pressure/RPM to simulate a feathered prop.
(3) NO simulated asymmetric at night.
(4) Going beyond the above was a dismissal offence, such was the risk analysis of any training value versus the increased opportunity for disaster, almost always fatal.

Works for me, and for anybody who works for me.

The FAA, some years ago, published an interesting analysis of outcomes of in-flight engine failures in singles versus twins, as always most instructive.

In short, subsequent to the failure, the fatal accident rate for the landing heavily favored the single, and where the twin resulted in a major accident was almost always because of asymmetric mishandling, resulting in loss of control in flight (there is some sobering in-flight genuine footage on YouTube, illustrating how sudden and violent it can be getting below Vmca in a FAR 23 twin), whereas most singles arrived back at ground level more under control than less.

In other words, a FAR 23 twin is not just a single with twice the chance of engine failure, it is worse than that.

Tootle pip!!

[Creampuff]

The ATO himself/herself, and not the student, has failed the test if mixture or fuel off is used to generate the failure on take-off.

Under any analysis, that's putting the aircraft at significant risk.

I don't even know why this discussion is still occurring.The discussion is still occurring because there are still people who'd like matters of aviation safety to be determined by data and rational decision-making that takes the data and relative risks into account.

I can show you a certified and confirmed serviceable aircraft (including a confirmed serviceable fuel system) whose engine will continue to run even with the throttle closed and the mixture set to idle cut-off. How can that be so?

On "any" evidence-based "analysis", pulling the mixture control does not have the effect of turning the "fuel off" on many aircraft. On "any" evidence-based "analysis", on some aircraft the simulation of an engine failure by pulling the throttle produces an operational environment that is unrealistic of the usual causes of engine failures.

Don't you think it would be safer if the method of simulation was decided on the basis of an understanding of the particular systems on the aircraft in which the simulation is occurring, and a consequent understanding of which method is - on balance - least unsafe?

[A37575]

Don't you think it would be safer if the method of simulation was decided on the basis of an understanding of the particular systems on the aircraft in which the simulation is occurring, and a consequent understanding of which method is - on balance - least unsafe?


You are making a mountain out of a mole hill. The object of training for an engine failure in a twin engine type as above, is a handling issue pure and simple in that the pilot applies flight controls to keep the aircraft right side up.
It would be unrealistic to conduct engineering flight tests for a Tiger Moth to a Cirrus or for a DC3 or to a Seminole and all types in between, to determine whether a throttle closure or fuel/mixture cut is most desirable from engine handling point of view.

In a single engine types such as typical Cessna or Warrior, it is normal to close the throttle to simulate engine failure for a practice forced landing. Why not cut the mixture to simulate the engine failure in a single? Answer: It may not start again and you are left with a real forced landing with its associated obvious drawbacks.

Yet some are happy to cut the mixture to simulate engine failure on a twin. Fine above circuit altitude with time and altitude to spare. But what if that engine doesn't start again? For one you are stuck with a windmilling prop until the penny drops you have a serious handling problem and you are forced to feather the prop for real. Not much fun at low altitude after take off and steadily degrading airspeed.

A pedant would claim the mixture cut at low altitude is good from the engine handling point of view and that this overrides safety considerations. Someone else may have the view that safety considerations override engine handling considerations and for that reason prefer to close the throttle to idle and thus have instant power available if needed

This is the point made succinctly in the warnings via various State safety authorities and the NTSB that all things considered, mixture cuts in twins at low level to simulate engine failure, are simply not worth the risk of mishandling by a student/instructor. Perhaps the time has come to realise the subject in Pprune has run its course with people agreeing to disagree. :ok:

[gerry111]

You are making a mountain out of a mole hill. The object of training for an engine failure in a twin engine type as above, is a handling issue pure and simple in that the pilot applies flight controls to keep the aircraft right side up.


If only it was that simple. There's been a number of double fatalities over the years in Australia, where the instructor also lost control while simulating an EFATO in a piston twin.

Creampuff's argument appears to me to be: That not all piston twin aircraft have similar engines nor fuel systems. So there's no 'one size fits all' on how to do EFATO's in a twin.

Understanding how your aircraft's engines and fuel systems really work must add to the safety of your flying. (And I don't mean some of the OWT's that many of us learnt from our GA instructors, all those years ago.)

[Sunfish]

I think the point here is that there are Two issues mixed up here; training and qualification.

By definition training involves the possibility of the student failing at first attempts to perform the required action. Hence there must be an allowance made for the instructor to rectify mistakes in good time.

As for qualification. I fail to understand the logic in assuming that if a pilot can handle EFATO once during a test, they can therefore handle the same failure, possibly in a different environment in future.

Then there is the argument for professionals about the risk mitigation possibilities in actually performing an EFATO. Clearly, training fatalities suggest that a realistic practice is as dangerous as the real thing.

To put that another way, does one test the operation of a firearm safety catch by loading the weapon, pointing it at your head and attempting to pull the trigger?

[ForkTailedDrKiller]

Would be interesting to see some stats on engines that have failed to restart after the mixture was used in an EFATO drill - with the engine to being returned to zero trust immediately after the 15-20 secs to complete or stuff up the drill, not left shut down with or without the prop feathered.

Seems to me that when you hear or read about an EFATO drill that has gone bad there is likely to me more to it than just using the mixture to briefly shut down thrust from the engine.

Dr :8

[27/09]

Would be interesting to see some stats on engines that have failed to restart after the mixture was used in an EFATO drill - with the engine to being returned to zero trust immediately after the 15-20 secs to complete or stuff up the drill, not left shut down with or without the prop feathered.

Seems to me that when you hear or read about an EFATO drill that has gone bad there is likely to me more to it than just using the mixture to briefly shut down thrust from the engine.

Dr :8

I agree with your last sentence.

I have no idea how many engine failures I have initiated as an instructor but it would be in the 1000's. They have been initiated both by closing the throttle and by mixture cuts. The only method that has ever caused me to wonder if the engine is going to come back to normal power have been those initiated by closing the throttle.

[megan]

To put that another way, does one test the operation of a firearm safety catch by loading the weapon, pointing it at your head and attempting to pull the trigger?Some folks do that Sunny, but they have the safety in the off position to see if it works. And it usually does.

[boofhead]

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.

The procedure for an engine failure while on the runway (although usually at speeds less than 30 knots) is to pull the mixture to cause the engine to stop. The student will feel the airplane start to swing and should immediately pull both throttles and stop the aircraft. The instructor, meanwhile, is guarding the mixtures and if the student fails to pull the throttles, s/he should then pull the other mixture off. This will prevent a loss of control and is an effective way to teach engine failure at low speed. Unless the pilot is trained in this, I will not sign off a multi engine rating. It is an important part of twin flying and should be done, safely of course, and this procedure meets that test.

[KayPam]

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.

Why not feather the dead side immediately ?

[boofhead]

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/aair200000492_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 :ugh:

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 :ok: 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.

[gaunty]

It is not often that I am in complete agreement with Leadsled re Part 23 twin training. :ok:

On C441 in particular and Garretts in general, boofhead goes to the top of the class. :D:ok:

[Xeptu]

On C441 in particular and Garretts in general, boofhead goes to the top of the class.

I'm with Gaunty, Spot On

[A37575]

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.

[Tinstaafl]

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.

[Old Akro]

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.

In fact, I think the weight of historical evidence of pilots shutting down the wrong engine would illustrate the importance of a secondary check to confirm the dead engine.

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.

[27/09]

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.

[sheppey]

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.

[Xeptu]

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.

[27/09]

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.

Lets just extrapolate that scenario a bit further. If the pilot in question has misidentified and closed the wrong throttle, think how much more consequential it would be if he had gone directly to pulling the prop into feather without confirming by using the throttle.

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.

Yes, not being able to feather is a possibility but I'd suggest a very rare event and there are greater risks. Managing risk is so very important and I think statistics show very often pilots make a bad situation worse by rushing an emergency procedure. Taking time to properly confirm which engine has failed certainly reduces risk in my opinion.

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.

[sheppey]

The tuition needs to match the aircraft being flown.

Never a truer word.

[megan]

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 pathThe ITT/fuel flow will still be commensurate with the degree of loss of TQ, both low.

[Xeptu]

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.

[Xeptu]

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)

[Eddie Dean]

Damaged compressor, CT badly eroded, flanged adapted modulator over modulating.

[megan]

In the case of a second stage power turbine partial failure {burnt)Only happen if you don't write up those overtemps, or don't do trends.one of the engines hits an ITT limit well before takeoff torque is achievedIn one case it was grass packed in the inlet. Cold or hot end erosion, bleed valves.

[Xeptu]

very good, now the one you described, low torque, low, ITT, low fuel flow, whats wrong with the engine

[Xeptu]

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.

[27/09]

I thought the thread was titled Simulated engine failure after take off in light piston engine twins.

Have I miss read the title?

[megan]

whats wrong with the engineLow side fail. Never had one, have had a high side.