The Probability of an Engine Failure in a Certified GA SEP
 

This comment on the EFATO thread got me thinking.

Personally I think flight training spends an outsized amount of time and effort on bad occurrences that are quite rare and not nearly enough time on bad occurrences that are quite common.

If you are sitting at the edge of your seat waiting for the engine to fail on every takeoff and then are "surprised" when it doesn't than I think you are ascribing a much higher probability to the event than it warrants.

This does not mean you ignore the possibility of it happening. I think every pilot should review the EFATO vital actions prior to every takeoff and pay attention to the terrain surrounding the airport but an EFATO is just one of the many negative eventualities that could occur during the flight, many which are much more probable ( eg Carb icing).

The risk of most of these eventualities can be mitigated by a disciplined approach to flying, including good pre flight planning (Wx, NOTAMS, Fuel Calculations etc), effective checklist use and a good look out both in and out of the cockpit.

If those precautions are applied than an EFATO is very unlikely. If you look at the accident statistics the Least Common scenario is for an EFATO in for an aircraft that has

1) no outstanding maintenance issues,
2) Has sufficient fuel, no contamination, and from a correctly selected tank
3) Shows no anomalies during a complete and comprehensive runup
4) Was checked for Carb ice before lining up for takeoff, and
5) The engine gauges where in the green and the engine was developing full static RPM at the start of the takeoff role.

The accident statistics show that up to 80 % of SEP engine failures were caused by the actions or inactions of the pilot with fuel exhaustion/contamination/mis-selction and carb icing accounting for the majority of the engine failures.

I think it is important that my list of 5 actions are wholly in the control of the pilot and will dramatically lower the risk of an engine failure at every stage of the flight.

If you are slap dash about your walk around, rush through the runup and don't use a disciplined check list methodology, and then go out and do a bunch of PFL's; yes you will be safer than doing no training but you will be acquiring skills to deal with the engine failure you very likely have caused.

Engine failures do occur but I would strongly suggest that if you are serious in preparing yourself for this eventuality your training should start with reviewing actions that will reduce the possibility of the engine failure and then progress to practicing the actions that could restore power in the event of a failure and only then work on actually flying the forced approach manooever.

Well I am done for now but I expect this should engender a lively discussion. :ooh:

Big Pistons, I marvel at your faith in the collection of stressed rotating and reciprocating parts, held apart by a microscopic film of oil without which it will destroy itself within seconds, that comprises an aircraft engine. And we are talking not modern highly-developed, superbly engineered, highly computer-controlled very well developed modern automobile engines, but an old technology air cooled 1930s engine similar to what used to power classic Brit motorbikes, only larger.

You say:

The engine that part-failed on me ticked all those boxes. So did the Lycoming in the PA38 in which the guy I knew died when it stopped at 300 feet.

There are so many design faults in a Lycoming it is a surprise it runs for any length of time. So always be prepared for it to quit or run at reduced power.

Lycoming say they need to be run 40 hours a month to meet TBO and any failures are down to pilot handling ya!!.

So take care.

And of course aircraft engines run at far higher power settings for much longer than a car engine does. At take off it runs at full power from near-cold for quite a long time. So even if it was as well engineered as a car engine (it's not - it's crude old technology) it would be less reliable.

BPF

Aviate Navigate communicate ? Surely an engine failure at low level means you should be putting your full attentions into flying the aeroplane and selecting a suitable landing area not head down fiddling with mixture controls, fuel selectors etc ? that surely is the way to loose control and crash?
Too many fatal accidents are caused by pilots not aviating and putting their attention elsewhere trying to restart an engine at 200 feet is a big mistake

Pace

From what I recall the engine partial failure left you with enough power to maintain level flight and re-position for a landing. I do not mean to make light of the fact that you successfully dealt with a very significant emergency but the engine did not "fail" in the way people are talking about in the other thread.

As for the Pa 38 crash the accident report stated the cause of the crash was


I would suggest that there was at least some indication that the fuel valve was not working properly and thus the potential to have prevented the engine failure was present. I also find it hard to believe that an engine starved of fuel did not give some indication that there was something wrong on the takeoff run.

I think it is also very unfortunate the accident report stated that there appeared to be no attempt to lower the nose after the failure. The climb attitude was held until the aircraft stalled, although tragically the pilots only reaction appeared to do the least important thing of all, make a radio call.

I realize that 2 people died in this accident and my remarks may seem insensitive but I believe this accident has lessons that should not be glossed over.

Engines with properly selected fuel selectors don't stop. If there is any doubt about how the selector feels or whether it is properly positioned than you should not takeoff.

As has been already mentioned in many other threads the first action by the pilot when confronted by an EFATO must be to lower the nose. If you do nothing else but keep the wings level you will probably survive, but letting the aircraft stall at low altitude is a death sentence.

Just interested to know which PA38 accident we are talking about here?

Slightly off thread I find a lot of pilots do not turn the fuel selector to OFF at the termination of a flight and many are not aware of the safety catch to do so. This action confirms that is physically possible to select OFF, reminds the pilot how to do so (both actions required for fire in flight or for crash/committal checks in event of engine failure) and procedurally is a checklist item.

Debatably this was an "outstanding maintenance issue"? Or maybe this issue should have been rectified before flight.

The last two SEPs which apparently reputable UK flying schools presented to me for flight had long-running engine maintenance 'issues' which the schools concerned knew about and had chosen not to resolve. One of them had two problems each of which was unacceptable.

I don't remember that sort of thing being a feature of my (halcyon?) days as an FI. I do wonder if it is perhaps quite common nowadays...

First of all I would like to draw attention to widen scope. Risk mitigation of EFATO is probability and severity, so high degree of attention is to be spent mostly for the second.

Yes, the 5 list does cover a great number of fatalities reasons and I often find myself shaking head when reading accident reports, but, being a pilot means also to do mistakes, frequently. The beauty is to do only the once not killing you.

In our current world of full-insurance-coverage thinking it may appear archaic to be aware of death, but this also make part of the soul of a pilot (in contrast to a flying bus driver). So what is all that excitement about? I do a fatal mistake, I die, so what? The only thing to take care of is to not hurt somebody else upon doing so.

Big Pistons, you may read elsewhere in one of these EFATO threads that partial engine failures lead to more deaths that complete failures. Having had one, I concur.

The PA38 I referred to did indeed have a faulty fuel selector, but there is nothing in the AAIB report that says that should have been noticed by the pilot. My understanding is that he moved the selector handle to the correct position, but wear in the mechanism meant the tank was not correctly selected.

One guy died in hospital after the crash - the pilot. His passenger received terrible burns but survived.

Where I would question that pilot's actions prior to T/O is that he changed tanks then took off, so any problem with that tank - fuel, selector, or whatever, wouldn't manifest itself until he was in the air. I used to fly that very aeroplane, and I used to change tanks before the power checks, so plenty of time for subsequent problems to happen while we were still on the ground (they never did, but that was when that aeroplane was much newer).

Whatever, in my book one should be EXPECTING an engine fault at any time in flight, but especially at T/O. This doesn't mean 'sitting on the edge of the seat', merely not being surprised (OK, not being overwhelmingly surprised) when the power dies away at 300 feet.

I think there is an issue here, comparing apples with pears. There are distinct markets, the club rental market, the owner/operator market. Both hinge on knowing the aeroplane. The owner has a distinct advantage. He, to a certain degree, knows what he has done to his aeroplane, (or should do), therefore in the frame of EFATO, he should and could do all he can to mitigate the occurrences. Proper/correct maintenance regimes, proper and diligent walk rounds, adherence to owner SOP.

The renter relies on someone else having done all of the above, and places faith on the rental organisation to have a duty of care. I have seen, and been in, some right buckets, but I had the go/no go decision. I have seen some poor decisions made by owners, and again have invoked my go/no go decision.

Life is chance, therefore, if we could predict when the engine may fail, we would all be very rich. I do not think stats exist of failures in the two categories mentioned above, but I would maintain that pilot error is still the main cause of death, even when the engine quits. We generally do not hear about successful engine failure landings, but we tend to here all about them when they go wrong.

"Slightly off thread I find a lot of pilots do not turn the fuel selector to OFF at the termination of a flight "

Personally - I never do this as I think it is safer to keep it on.

If I walk up to the aircraft and it is sat in a pool of fuel I am not going to fly it! If I switch the fuel off I may not find out about the issue till later...

The fuel selector often has no maintenance schedule. I know of a number of aircraft that have suffered fuel selector failure at the point of max fuel pressure - normally just after takeoff and the pilots have been killed or burned - and one when the pilot was sprayed with fuel but got the cub down and it did not go bang.

I check my selector every 3 months. This confirms it is working.

Rod1

I never do. As Part of Pre-flight I do check it is movable and turn it one time left-right-both-off, so at latest upon engine start I have a fair chance to see trouble on the ground. If I would turn it off, fuel may evaporate during parking and the lines may not be fully filled (had this once a couple of years ago), plus with open valve any small leakage in the fuel feeder will be smellable.

Ditto, I always leave my selector on a tank, never put it to OFF.

I've had several car engines fail on me and 0 aero engines.

I have had three in certified Pistons, 1 in permit Rotax and 2 in turbines.......

How often do you PFC your car?

I had a BSA 650 in the early 60s that never let me down once, from one end of the country to the other in some pretty filthy weather at times.
I now have it's bigger brother in the form of a Continental C90 up front and it too has never missed a beat in the 7 yrs it's been pulling me around. 3100 hrs in the book.
I've just fitted an electric fuel pump which the a/c didn't have before. If there is a time when I might expect an EFATO it will be the next time I leave the ground. There will be a considerable amount of taxi time & full power run ups before that happens.
I wonder how many failures occur just after maintenance, and how many are maintained by the owner, (permit types) versus maintained by commercial ops?

Well yes, that would have caught one of them, I don't fly off in a plane with an oil pressure indication reading zero.

(Actually it was the tachometer reading zero, but that was, if I'd known the car's system well enough, an indication of an oil problem.)

Then how do you know you can turn it OFF if you need to?

I have had two engine failures (one partial but could not maintain height). Both were due to professionally supplied parts or maintenance. In one case I had told the maintenance organization I thought there was an issue and had wasted significant time and money for no fault found till the other mag failed and I ended up on 1/2 a mag over Scotland (Robin DR400).

That is in around 1200 h, but both issues were in the first 600. I do my own maintenance now;)

Rod1

The Chipmunk has 2 fuel pumps, both mechanical diaphragm types, in parallel. Both feed the carburetor simultaneously and one is used to prime the engine as well, using a manual lever.

If the one used for priming fails you'd know because you'd not be able to prime the engine. But if the other one failed you wouldn't know you were relying on just one until the first failed as well (at some point after priming), when the engine would stop!

Because I ripped out all of the fuel lines, replaced the worn gascolator, renewed the selector, and at the 50 hr, and each annual we check it. I also check it once a month. The comment was I leave it on after each flight. Given I am the only one that flies my plane, I am quite happy with it.

Mainly due to this incident

http://www.iasa.com.au/folders/Safet...fueloffed.html

maxred, thanks! It's your train set so do as you think fit.

Regrettable though that accident was am not sure it proves much in the respect we are discussing. But I would prefer to read the whole accident report rather than a news article summary.

I can see some of the counter arguments to not turning the fuel off but in the training context I still think it should be taught.

Firefly, I agree that within the training context, all procedures should be taught in line with the POH of type. Generally training types, if such a thing exists, are designed to ensure that the unwary, do not get trapped. Therefore, on, off, on again, training rote, getting the student into the ABC mentality. As you progress though, particularly with older types of aeroplanes, certain idiosyncrasies crop up, often peculiar to model, and individual airframes.
The early Bonanzas, in particular, have some strange and peculiar fuel set ups. Therefore for me, I keep it on selected tank. At least I know the engine was running when I landed:8:8

I've had three engine failures very low after takeoff. One, a fuel interruption, put me back on the remaining runway (I could not have made it past the end :D), another, at only a couple of hundred feet was ice crystals in the fuel, into the next field, no damage, and took off later when resolved. The last was the mouse nest of insulation from under the glare shield, being sucked from the air hose, into the venturi, with the application of carb heat, again, into a field, no damage, towed it home.

Very much worse has occurred during testing I was doing, but I was up high, and testing for it - it happened! Consider the tried and true C 180. Owner installs a STOL kit - yippee! Look at those high AoA's and steep departures it can do now (not safely). Then owner installs a larger carburetted engine - still no fuel pumps. Wow, it goes up even better now! But.....

When you combine the higher pitch attitude capability with a STOL kit, with the higher fuel flow demands of a bigger engine, you can get the plane into a very nose high danger corner, in which it will quit, and from which recovery to gliding flight is unlikely. The carb inlet is actually higher than the tank outlet - 15 degrees pitch up is in the danger territory. I agree, this is far away from the regular airport circuit technique, but there are pilots doing, it and I have done the testing to demonstrate that there is a much greater risk of EFATO doing this. Floatplanes are more vulnerable, as pilots are sometimes trying to outclimb terrain. A friend of mine, a very competent, though perhaps a bit complacent, friend of mine broke his back in the resulting crash - and he has heard my admonishments on this (beforehand).

So EFATO's are happily rare, and there are things you can do to make them even less likely. But, flying with "room" for them to happen without ruining your day, is a good idea when you can.

To give a better idea of why extra speed is better than extra height immediately after take off here is a good example.

We were scooping water on a fire one day when I had an engine start to fail just after lift off from the water it happened just as I reached my start climb speed which was ten knots over the airplanes normal climb speed.

The extra speed gave me the inertia factor to allow me to scratch my nuts while I decided what I was going to do with the beast.

So... once I was sure I was doing the correct thing I first dumped the nine thousand pounds of water and feathered the prop......did the shut down stuff in the check list and flew seventy five miles back to home base....

....fortunately I got it shut down in time to save the engine because it had blown a cylinder and the piston had a big hole in it.

But those full power settings are quite frankly derisory. An O360 displaces nearly six litres, yet typically produces 180hp or less. That's just under 33hp/litre. My 1979 Austin Maxi was putting out around 58hp/litre! Anyone who takes off with a "near cold" engine deserves everything they get.

As I said in an earlier thread, I managed almost 1200 hours with a Rotax 447 two stroke, and didn't have it stop once. On two occasions I encountered a reduction in power, due to water in the premix fuel - it wasn't visible separately, but formed a waxy deposit in the filter. I also had a brief run of misfires, which eventually turned out to be a faulty ignition harness. This could have affected any petrol engine. I don't believe this otherwise good record was down to luck, but sensible engine handling and regular maintenance, which I carried out myself.

If I was constantly worrying about things going quiet, I would have packed in long before other circumstances intervened.

Pram - here's some news for you. Every piston-engined aeroplane, especially air cooled ones, on its first flight of the day takes off with a near-cold engine. It takes a long time at high power for the entire engine, and its oil, to get up to even temperature throughout. You can't achieve that in ground running, especially with an air-cooled engine. Some bits will get very hot and will be under-cooled on the ground, while, other bits will stay relatively cold, so it's bad practice to ground run a cold engine for long periods.

This is why an aeroplane that is grounded for a long time should never be dragged out, engine run, then put away. If you start it up, fly it! If it can't be flown, don't start it up!

Get it into the air once the oil is hot enough, and get the whole engine warmed through without the very hot spots (heads, exhaust valves etc) getting too hot.

You list five things that can help to reduce the incidence of engine failure.
None of these things eliminate it.
Imagine flying at night or in acutal IMC or, better yet, night actual IMC in a single and hearing the sudden silence, despite your having done everything possible to maintain the engine and fuel supply system in good operating condition.
It happens, and your survival will depensd upon your having thought ahead of what your alternatives might be.
Nobody would like facing a forced landing at night or in bad weather, but the time may come when there isn't a choice.
You can reduce risk through proper maintenance, but you can't eliminate it.
When you rely upon the continued operation of the one powerplant to get you through a bad stretch, you're undertaking an additional risk.
The risk of engine failure can be reduced but not elminated.
The probability of a bad outcome following an engine failure can also be reduced, but only if we recognize the possibility and plan for it.
It's not a matter of if, it's a matter of when if you fly enough hours.

Exactly:

How many here would fly only over the north Atlantic beyond gliding distance of land in a single engine anything?

In other words...every flight would be over water for your whole career.

I totally agree with your statement, but this is a case of "what should be" vs "what is". What "should be" is that pilot induced engine failures are very rare, unfortunately "what is", is the fact that a very large percentage of engine failures reflect the lack of attention to piloting fundamentals.

I see a collective denial of this fact throughout GA and strongly believe the path to better outcomes is not practicing hero turn backs or perfecting your PFL flight paths, it has to start with a industry wide concentration on the importance of the 5 steps

However engine do fail despite the best efforts of the pilot and so risk mitigation procedures should always be applied.

For me that means the following.

For over water flight I try to stay in gliding distance of the shore and always wear a horse show type constant wear life jacket.

For night flight I will only fly multi engine aircraft at night, except that I will fly a single at night but only in the circuit.

I am struggling to see how procedures appropriate to a 2 crew mutli engine flying boat with a disposable load have anything to do with EFATO's in SEP's

Oh yah silly me I forgot the point of the post was to make sure nobody forgot about you skygodly powers. :rolleyes:

It is directed at using speed in any airplane BPF.

This bit was meant to point out the extra speed means the inertia gave me more time to make a safe decision in how to react.


You seem to have missed my point completely B.P.F.

And personal insults do not improve this discussion.

IF you are flying at best glide speed in the majority of single engine light planes made by well known manufacturers, please tell me how there isn't enough speed to flare?

Best glide speed should give you the best (farthest) glide in a no wind situation.

And certainly there is enough energy to arrest the descent at the very end of the flight.

Excess speed might reduce the distance of the glide. AND while you may not need the distance, on the other hand you might.

We aren't talking about flying borate bombers, PBYs or anything else. Just little pipers and cessnas and whatever things the british have.

I am well aware that this is a private pilot forum, however private pilots are quite able to understand the laws of physics and aerodynamics and also understand these laws apply to all aircraft.

But if it it is creating a problem using aircraft other than little Pipers and Cessna's I can probably use them as examples so I don't irritate or confuse people like you Skyhigh.

O.K. ? :rolleyes:

No response to the point I made about adequate energy to flare at normal best glide speed.

Of course there is adequate energy to flare at normal best glide speed, I don't see anyone stating there isn't.

Now, now, boys, lets keep the party polite!

It is always entertaining for the rest of us mortals to see the pilot with the highest opinion of his own ability come unstuck.....

So let me lighten this thread with a story about an Engine Failure on Takeoff that completely satisfied all the witnesses.

For the first time EVER, the Chief Flying Instructor's wife agreed to come up with him in the motor glider, a Falke. (She felt safer in an aircraft with an engine!) The craft was preflighted. Taxied to the end of the gliding club runway, engine run up, and takeoff, towards the clubhouse, commenced. At a height of approx. ten feet the engine stopped.

(The equivalent for us as a cable break at low level) The Chief Instructor handled the power failure with superb technique and managed to stop before flying into the clubhouse. His wife climbed down and said she was never going up again, never!

The Chief Instructor was incandescent. "This airplane is unfit to fly! It will have to be grounded immediately until the Engineer has gone over this engine! Somebody could have been hurt!" etc etc etc.
Until another pilot, well experienced with the Falke, asked the question
"Did you check that the fuel was turned on?"

Silence.

Confirmation. The fuel was NOT turned on. (The custom had been that the fuel was normally left turned on...on this occasion a visitor had ended his flight by turning it off.)

The wife of the Chief Instructor, when sitting in the RH seat of the Falke, and being of somewhat ample proportion, made it impossible to verify the position of the fuel cutoff lever.....

I'm not sure whether a formal report was ever made, but we never let him forget it! No names, no pack drill.

When I've got a really important decision to make, I scratch my.... head. ;)

Just to be precise, I've quoted the term "maximum" (rather than "best") from a selection of Cessna flight manuals to which I had referred. The intent being that gliding the plane at the speed for maximum glide will take you the farthest per altitude. That may be "best" if you need to make it to shore, but it may be far from the best, if there's a great landing spot right ahead of you, with some obstacles on the way, and a gusty wind. The pilot needs to make an informed decision as to what the "best" glide speed will be for each situation, and aim to be at that or a faster speed when an engine failure would be more critical.

So referring to:

A steady glide approach in a C 206 at gross weight at 65 knots will take you a long way (I've done it from 13,000 feet once), but if you enter a flare at that speed, things will happen very fast. So you are arresting a descent "fast", that means a more sudden change in approach angle, so more G, and trading speed for G more. If you get it wrong, there's nothing left at the bottom but a thump. When you look at the flight path, there will be a very small radius to the change from approach angle, to landing path. Small radius + bigger G = greater trade of energy. Or, from a faster glide approach, with a somewhat more steep angle, you have more stored energy, so that radius will be much larger, and the energy required to arrest the descent less, so you'll have less loss of speed, and more time to get it right.

This was taught to me during flying boat forced approach training, where a full stall landing, or worse, dropping it on, is very undesirable. My mentor told me to imagine I was going down a roller coaster, and at the bottom, smoothly pitch up as though to follow the rails - it worked perfectly. If you're a bit fast, just aim short of the intended landing place, and you have lots of control as you slow crossing the fence.

Though I do realize this it not the rotorheads forum, helicopter gliding none the less provides some insight to this. When gliding a helicopter, energy is stored as rotor RPM, up to 110%, more is better = longer to use it up flaring to land, so less rushed, better landing. But the maximum glide distance in a helicopter will be at a lower rotor RPM, because you're not storing energy in the rotor, you're only using it for the minimum lift you need to fly. If you flare from a low rotor RPM, things will happen really fast.

So, to a point, speed is your friend during any forced landing - speed = choice. Speed is easy to get rid of, when you no longer need it (you can slip a Cessna right onto the surface if you need to).

And it's worth remembering that if you really did get the speed wrong for your selected landing spot, you'd rather cross the near fence too fast, and not be able to stop for the far one, than to not make it over the near one, and crash into something at speed, without the opportunity to get the plane on the ground, and slow down for a while.

When it suddenly goes quiet, decisions must be made with little head scratching - 'cause your thinking, planning skill and experience have covered most of the factors.