Piston engine reliability (questions for high time pilots and mechanics)

Henning has the right idea.

Part of the reliability of modern vehicles is because of FADEC tecnology. You can't detonate them, overheat them, run them too hard when cold (still a good idea to take it easy) and you don't have problems with build up because the mixture is always perfect.

Yes FADEC does introduce complexity and new failure points - but cancels them out with the above benefits. Especially if you share your plane with morons (renters) Properly back the system up and the package is just as reliable.

Not to mention the fuel savings...
 
Wow, my experience is opposite. I have only one personal aquaintence that was killed in a plane (airshow accident) but I know a couple dozen people that have been killed in car accidents.

Go try and buy reasonable life insurance.
 
maintain it and fly it like the airlines and it will be as safe as the airlines. The most dangerous component with an operating engine is the 4lbs of squishy water between the pilots ears.
 
@DougBader - I never knew that the rear engine in the Skymaster is referred to as the 'fear' engine . . . . learn something new every day!
 
The number of GA deaths per million flight hours, is 22.43.

This means once you have 2000 flight hours, your odds of dying are. 4.5% (this incudes pilot error as well).

If we asume that 2/3 of those are pilot error, we are down to 3%

I am 43 years old. My guess is it will take me 20 years to get to 2,000 hours. So 3% is only 6 times higher then my odds of dying from natural causes in that time frame anyway.

I like those odds :)
 
Part of the reliability of modern vehicles is because of FADEC tecnology.
But for some reason FADEC seems very slow in making its way to piston aircraft. Is there any factory new Cessna or Piper piston with FADEC, or a Cirrus, I don't think so.
 
Most non fuel related 'engine failures' are actually accessory failures like points in the mags.
 
But for some reason FADEC seems very slow in making its way to piston aircraft. Is there any factory new Cessna or Piper piston with FADEC, or a Cirrus, I don't think so.

Pilots are too cheap to spend the extra money up front so they pay more by the hour later. Continental has them available up to 350hp rated to run on 94UL. Since I have pretty new engines, I'm hoping the Diesels will be available when I come due or before.
 
maintain it and fly it like the airlines and it will be as safe as the airlines.

You mean pencil whip the maintenance, overfly AD's, and get away with anything possible? That kind of maintaining it like the airlines?
 
I've had a few mag failures that resulted in very reduced power.

I've had had one catastrophic engine failure (valve froze then broke off and bounced around in the cylinder blowing a hole in the top of the piston).

The mag failure is too common, and usually due to inadequate maintenance.

Busted valves tend to be rare, but are often due to corrosion on the valve stem. They get pitted, which weakens them. Infrequently flown airplanes can have this issue.

Most common cause of failure in carbureted engines is carb ice. Distressingly common, and entirely due to improper or nonexistent training and understanding of the phenomenon. Too many pilots think it's only a wintertime thing and aren't prepared for it any other time; others see a power drop, pull the heat and see a further power drop so they shove the heat off again. The icing continues until the engine quits. Fuel starvation (whether or not there's fuel in the tanks) is the next big cause of failure, and oil starvation follows that (leaking old hoses or fittings, or inadequate preflight checks) and the actual mechanical failure is at the bottom of all engine failure causes.

I had two failures before I had 800 hours. The first involved a carburetor that came off because the bolts weren't safetied and the second when the crankshaft broke due to a long-before propstrike that started a crack that the rebuilder didn't catch (and probably didn't even look for). Both incidents involved inadequate maintenance; old airplanes maintained on the cheap.

Dan
 
The mag failure is too common, and usually due to inadequate maintenance.

Busted valves tend to be rare, but are often due to corrosion on the valve stem. They get pitted, which weakens them. Infrequently flown airplanes can have this issue.

Most common cause of failure in carbureted engines is carb ice. Distressingly common, and entirely due to improper or nonexistent training and understanding of the phenomenon. Too many pilots think it's only a wintertime thing and aren't prepared for it any other time; others see a power drop, pull the heat and see a further power drop so they shove the heat off again. The icing continues until the engine quits. Fuel starvation (whether or not there's fuel in the tanks) is the next big cause of failure, and oil starvation follows that (leaking old hoses or fittings, or inadequate preflight checks) and the actual mechanical failure is at the bottom of all engine failure causes.

I had two failures before I had 800 hours. The first involved a carburetor that came off because the bolts weren't safetied and the second when the crankshaft broke due to a long-before propstrike that started a crack that the rebuilder didn't catch (and probably didn't even look for). Both incidents involved inadequate maintenance; old airplanes maintained on the cheap.

Dan
Over the years on these boards I have heard that exact tale told numerous times. "I pulled the carb heat but that just made it worse so I shoved it back in...":nonod: of course it did, that means it was carb ice and it was starting to clear...:mad2:
 
I have just a bit short of 2200 hours in piston aircraft, (13600TT), and have never had a piston engine failure. Had three in turbines. One from a bird, one from a fire, one from a compressor blade who didn't play well with others.
 
Electric:
First, you are the weak link in the plane, not the engine...
Second, I'm not sure you are cut out for being a pilot - that is a whole lot of fear I'm smelling..

Since when ignorance become the right attitude for a pilot? As a pilot in command, it's my job to take charge of the factors that may effect the well being of my aircraft, my passengers and myself.

Stay on the ground and read all the reports you want. :rolleyes:


Do you really think you are a safer pilot reading those reports? :no:

Yes, knowing what did not work for others allows for better in flight decisions... I'd rather learn from the mistakes of others.
 
There's nothing wrong with mishap reports. Don't allow the simplicity of being able to review a fatal incident from the safety of an armchair, however, lure you into the belief that such an incident is easily dismissed or invalidated. It's very easy to read an account of fuel exhaustion, for example, and dismiss the airman as an idiot, and move on. It's not hard, when circumstances begin to combine, to find yourself pushing toward being that same idiot, however, and it's at times like that when remembering the mistakes of others can help you.
 
Over the years on these boards I have heard that exact tale told numerous times. "I pulled the carb heat but that just made it worse so I shoved it back in...":nonod: of course it did, that means it was carb ice and it was starting to clear...:mad2:

Reminds me of my one and only encounter with carb ice. I was a freshly minted private pilot, flying the C172 I learned in, and took my checkride in.
It was about 65 degrees F OAT and a really humid day. I had just taken off from a controlled airport and was climbing thru 3000 MSL when the engine suddenly dropped a couple hundred rpm and started running a bit rough. I did a quick mag check and that wasn't the problem, so I was preparing to tell the tower that I was going to turn around and come back to the airport, when I heard the voice of my CFI in my memory and pulled the carb heat out all the way. The engine started running very badly, dropped a lot of rpms and was sputtering, then when I was just about to key the mic, the engine roared back to full power and a big smile came over my face. Carb Ice! So that's what it's like for real.

I flew the rest of my flight with the carb heat on and the mixture pulled back just a little bit. Never experienced it again since then, but it was a learning experience. I never worried too much about carb ice in my Cherokee because I knew it was much more resistent to developing carb ice than the Cessnas, but in my RV-6, I know the carb heat system is a much more marginal heat-producer, so whenever conditions are favorable for carb ice, I'm running the carb heat. ;)
 
I had a 152 ice up around 5k feet in the summer. Skimming the top of a thin wispy cloud layer. Also worth mentioning I was at a very low cruise power setting
 
in my RV-6, I know the carb heat system is a much more marginal heat-producer, so whenever conditions are favorable for carb ice, I'm running the carb heat. ;)

Get a carb temp gauge, they aren't expensive and if you have an engine analyzer (which you should) most models accept an input for carb temp. This not only tells you when the conditions are hazardous for icing, it also let's you trim the carb heat and/or mixture to get you just clear without giving up more power or efficiency than you need to.
 
It seems like everyone that has more than 2000 hours in piston aircraft had at least one engine failure. Is that really the case?

Highly doubtful, IMO. Not sure what the actual number is, though.

Would an engine that is well cared for vs the engine on a rental aircraft be significantly more reliable?

The rental aircraft might actually win the reliability battle even with not-so-great maintenance simply because it's likely to be flown often, so things don't get a chance to corrode.

How well can you manage the risk of mechanical engine failure (not related to fuel starvation, contamination, vapor lock or induction icing, only talking bout mechanical failures.) during preflight or during maintenance?

Take care of your airplane, or rent from those who take care of theirs. Fly often (this is probably the most important thing to do because it'll not only make your airplane happier and more reliable, it'll make you a more proficient pilot). Don't do dumb things - Check your fuel and oil and don't run out.

Are those "mechanical" failures primarily due to negligence/poor maintenance, or its a truly random occurrence?

Some of both - But again, I couldn't tell you what the numbers are.

How helpful is mutli probe engine monitor in predicting otherwise unexpected power loss?

Maybe a little. Keeping tabs on things via oil analyses, compression checks, etc. will also help you see when your engine's telling you it's time - But there's not a damn thing that will let you know ahead of time that your crankshaft or a rod is about to fail.

What can a renter (or perhaps an owner) do to significantly mitigate the risk of mechanical engine failure? (again talking about true mechanical failure, not fuel or induction icing related)

See above.

I don't mind taking risk, and I know that weather and stall/spin accidents take way more lives than engine failures. However, unlike stall/spin and weather accidents, engine failures can not be avoided by training; and at least at this point, to me engine failure seems like a random occurrence that is very likely to happen if you fly long enough. Which is why it's one of the very few things that makes me nervous. :)

Stay nervous - It'll keep you looking for places to set down in the event the fan does quit someday. A complacent pilot who doesn't think about such things is more likely to get hurt or killed than a conscientious pilot who's constantly paying attention.

And keep reading those NTSB reports. You must learn from the mistakes of others, you'll never live long enough to make them all yourself.

FWIW - I don't consider myself "high time" by any stretch of the imagination - I just crossed 1000 hours. But, that makes for easy math! In that first 1000 hours, I can think of only one partial engine failure (on a twin) - And I still had maybe 50% power or so. Resolved the problem and completed the flight. I've had two vacuum pumps fail, both in VMC. I don't think I've ever had a major electrical problem. I've gotten carb ice a few times, and I've had one engine decide it didn't want to fly on that cold of a day (precautionary turn back to the field, but the power loss wasn't significant - Mixture just couldn't get rich enough for the ultra-dense air and the engine wasn't happy). These are things that are easily manageable by anyone who trains diligently and stays proficient.
 
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Thank you Electric for asking the questions; I learned some useful things.

From the responses I've read, I'm glad to hear no one mentioned (yet) cases of in-flight fire. I will likely never fly a plane I call "my own", but even while renting (if I eventually get a certificate) I will consider learning how to use a fire estinguisher in flight and then get one I can carry in whatever I will rent.

(My school actually has a neat C150 that has mounted in-between the seats a fire estinguisher.)
 
From the responses I've read, I'm glad to hear no one mentioned (yet) cases of in-flight fire. I will likely never fly a plane I call "my own", but even while renting (if I eventually get a certificate) I will consider learning how to use a fire estinguisher in flight and then get one I can carry in whatever I will rent.

I didn't mention it, because we're talking about engine failures.

I've had several inflight fires. The last one was a new dual electric hydraulic pump installation in a turbine PZL M18T Dromader that caught fire as I was landing. I flew the overhead and by the time I passed over the numbers, couldn't see much of anything.
 
Thank you Electric for asking the questions; I learned some useful things.

From the responses I've read, I'm glad to hear no one mentioned (yet) cases of in-flight fire. I will likely never fly a plane I call "my own", but even while renting (if I eventually get a certificate) I will consider learning how to use a fire estinguisher in flight and then get one I can carry in whatever I will rent.

(My school actually has a neat C150 that has mounted in-between the seats a fire estinguisher.)

I kinda had one. I was descending out of the mountains N of LA in a 310 and blew a head off a cylinder. When that happened the injector line broke and sprayed fuel on the hot exhaust which ignited and caused flames to come streaming out the nacelle vents. I just pulled the mixture and caged the engine and the fire went out in seconds. Landed uneventfully a few minutes later at LGB which was my destination anyway. They rolled the equipment but I didn't need it.
 
I didn't mention it, because we're talking about engine failures.

I've had several inflight fires. The last one was a new dual electric hydraulic pump installation in a turbine PZL M18T Dromader that caught fire as I was landing. I flew the overhead and by the time I passed over the numbers, couldn't see much of anything.

Oh boy.

What would you have done had this occured "way up there?" (i often read the poh emergency checklist so i have an idea what is recommneded in the C172, but would like to hear what someone experienced like yourself would do in the plane you fly).

Glad to hear you managed to get it on the runway. (i dont wanna get the thread off topic so i will open a new "in-flight fire" thread)
 
I kinda had one. I was descending out of the mountains N of LA in a 310 and blew a head off a cylinder. When that happened the injector line broke and sprayed fuel on the hot exhaust which ignited and caused flames to come streaming out the nacelle vents. I just pulled the mixture and caged the engine and the fire went out in seconds. Landed uneventfully a few minutes later at LGB which was my destination anyway. They rolled the equipment but I didn't need it.

Tell me this was at night :D You would've been a shooting star! K, I'm trying to put some humor in a burning situation.

i understand pulling the mixture - no air, no fuel. But what do you mean by "caged the engine"? Lucky you with that 2nd fan. Long Beach is nice, remember flying over Queen Marry?
 
What would you have done had this occured "way up there?" (i often read the poh emergency checklist so i have an idea what is recommneded in the C172, but would like to hear what someone experienced like yourself would do in the plane you fly).

"Way up there" in that airplane was typically less than 1000' AGL, usually 60' AGL or less. It was a SEAT (single engine air tanker), and was participating in a government spring training program, ironically on simulated fires. I was on the way back to the airport from my first two drops to get a load of water, and in a large, wide valley. I smelled smoke, and was idly wandering what the concentration in a valley that large, with wind, would be in order for me to smell a fire on the ground, as I couldn't see any smoke. That idle thought persisted until I passed over the numbers in the overhead pattern and turned left for a descending turn to final. As I did, the smoke got thicker and it became apparent that the fire wasn't outside, but inside. I landed on the mains, set the tail down, and as I rolled out, couldn't see.

A small hatch-window exists in the side door, and I opened that for ventillation. With no fans or forced air, however, there was no way of evacuating the smoke. I tried putting my face agains the hatch, but my helmet prevented that. I got clear of the runway and a pickup truck pulled in front of me, trying to direct me down to the tanker base. I didn't want to go there, but to go left, and as the truck finally got out of my way, the brakes failed and I began to turn left without any way to stop the turn. I noted a Cessna 150 tied down that looked like a good candidate for a prop strike. I had no more hydraulics, as the pump was on fire.

I was able to use a small aux pump to bring up about 500 PSI, enough to use the brakes to stop while I fuel-chopped the engine and popped the canopy doors. When I got out, the owner approached and asked why I didn't taxi to the loading pit I told him I was on fire, and he said "Yeah, your'e doing okay." I pointed to smoke coming out just ahead of the leading edge, and when I pulled the panel off there, we could clearly see the pump on fire. It turned out well enough, with minimal damage.

There were no emergency procedures attached to that assembly; it was a modification STC'd into the airplane, and came with no additional procedures.

Other fires I've experienced were electrical (circuit breaker panel in a Lear 35, AC panel in a M18T), and fuel (Janitrol fire on the flight deck in a PB4Y-2, twice), and a few other incidents along the way, including an engine fire in a C-130A, and a couple in the 4Y.

But what do you mean by "caged the engine"?

"Caged the engine" is a common use slang term in aviation meaning to shut down and secure the engine, usually by feathering the propeller. Feathering stops the propeller from rotating, and reduces drag by aligning the blades with the slipstream.
 
Tell me this was at night :D You would've been a shooting star! K, I'm trying to put some humor in a burning situation.

i understand pulling the mixture - no air, no fuel. But what do you mean by "caged the engine"? Lucky you with that 2nd fan. Long Beach is nice, remember flying over Queen Marry?

'Caging the engine' is securing it with the prop feathered so it's not turning and the drag is minimized. Yep, I flew over the QM many times, but the best landmark for KLGB is Signal Hill, the lights up on top of the tank can be seen flashing from Catalina and Big Bear.
 
Stay on the ground and read all the reports you want. :rolleyes:


Do you really think you are a safer pilot reading those reports? :no:

There is value in reading them depending on what you're looking for. I know based on NTSB reports that the Flybaby has an above average number of in flight wing failures. I also know the causes of the failures and know what to be watching on my particular Flybaby.

Had I not read the reports and just flew it -- I'd have no idea what to watch for. I'd wager those that died in them didn't know either.
 
Stay on the ground and read all the reports you want. :rolleyes:


Do you really think you are a safer pilot reading those reports? :no:

Depends what one learns from them. Most of them are just the same old predictable stupid crap but some of them get downright interesting. Thing about NTSB reports is you have to understand the material and vocabulary well enough to read between the lines to figure out the nitty gritty of the matter because they are written in a 'not to offend' manner and they have interest ways to call out stupidity and wrap it in technical jargon to obfuscate it, kinda like when Nixon questioned Dick Cavet's 'maternal lineage' during the TV interview.:rofl:
 
More reliable than the one in your car.
 
Yes, knowing what did not work for others allows for better in flight decisions... I'd rather learn from the mistakes of others.
Get yourself a copy of Aftermath, an excellent and not too long compilation of most educational airplane crashes (concentrates on the GA). By the editors of the Flying magazine. If you are capable of learning from mistakes of those pilots then that would be like the best $30 you spent in your life. The accidents they selected for this book are true gems and by the way there is an engine 'failure' or two there as well.
 
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More reliable than the one in your car.
I've had cars not start for various reasons but I can only vaguely remember having one engine failure in a car while it was running. That was many years ago and it had to do with the alternator. I don't log my "car hours" but I'm sure I have far more of them than airplane hours.
 
The SCAT tubing with the mud dauber nest is going to fail the crankshaft at overhaul. If the system has big enough holes for a wasp to enter, it has big enough holes for gritty contamination to enter. That condition should have been caught on previous annuals.

The carb heat inlet has no filter or screen on a Piper Cherokee. This is not the normal induction air inlet. The same is true on at least some Cessnas. This is a design condition, not a maintenance condition.
 
More reliable than the one in your car.

I have had an engine failure in my car. The result was I rolled to a stop on the side of the freeway.

If that was the worst that would happen in a plane, I doubt anyone would care about it.
 
More reliable than the one in your car.

Eh not too sure about that one. My 88 Lincoln Mark 7 with a 5.0HO has about 250,000 miles on the original motor. Automobile engines have a lot longer lifespan and overall seem a LOT more dependable then the motors offered in your typical GA aircraft. If I am mistaken someone please explain to me my error in this statement.
 
>> 1 out of 10 NTSB reports due to engine failure involves a fatality

Keep in mind... Engine quits, pilot lands aircraft on or off airport, no damage... Thus, no NTSB report. So your 1:10 is a sample of only the poor outcomes.

I've had two engine failures in 5,000 hours. Both resulted in on airport landings, no airframe damage. No NTSB reporting.

Paul
 
Eh not too sure about that one. My 88 Lincoln Mark 7 with a 5.0HO has about 250,000 miles on the original motor. Automobile engines have a lot longer lifespan and overall seem a LOT more dependable then the motors offered in your typical GA aircraft. If I am mistaken someone please explain to me my error in this statement.

LJS,

insufficient data in your posting. Are you saying that in 250,000 miles, less than a TBO run in many aircraft/engine combos, you have never had the engine quit once, even momentarily?

Paul
 
Eh not too sure about that one. My 88 Lincoln Mark 7 with a 5.0HO has about 250,000 miles on the original motor. Automobile engines have a lot longer lifespan and overall seem a LOT more dependable then the motors offered in your typical GA aircraft. If I am mistaken someone please explain to me my error in this statement.

It doesn't matter. An auto is an auto, and an airplane is an airplane. GA aircraft engines & auto engines are always discussed at length, within "experimental" aircraft forums, where actual results from using auto engine conversions are well known. More than not, the auto conversion never stands up to the reliability or performance of a purpose built GA engine. Some builders have success, but it's a lot of additional engineering & experimenting. In other words, if you think a modern auto engine is a well suited candidate for an aircraft, then you had better prepare to do a lot of research.

L.Adamson
 
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