Study of Reciprocating Engine Failures

Don't know if this well known already but
I hadn't seen it before.

http://www.aviation-safety-security....ive-study.html

It is a somewhat uncomplimentary (to the overseeing bodies)
review of aviation piston engine reliability.

On Apr 1, 7:08*am, wrote:
Don't know if this well known already but
I hadn't seen it before.

http://www.aviation-safety-security....ter/articles/c...

It is a somewhat uncomplimentary (to the overseeing bodies)
review of aviation piston engine reliability.

It is a 'publish or perish' piece yawn... It does not add anything
to what is known...

Yes, sudden, catastrophic, engine failures with no warning happen, but
they are the exception... The vast majority of sick engines complain
loud and long, and it is the dumb **** pilots who sit there - on their
brains - until the poor, gasping, struggling, engine finally comes
apart... Best you find something more likely to get all worked up
about - like getting hit by a meteor...

cheers eh wot

denny

On Apr 1, 7:52*am, Denny wrote:
It does not add anything to what is known...

Few reviews of existing information ever do.

Yes, sudden, catastrophic, engine failures with no warning happen, but
they are the exception... The vast majority of sick engines complain
loud and long, and it is the dumb **** pilots who sit there - on their
brains - until the poor, gasping, struggling, engine finally comes
apart...

I've heard that statement before - and it does not ring true. Mostly
I hear it from pilots who spend a lot of time banking on the engine -
flying single engine planes at night, in IMC, over water or rought
terrain, at low altitudes, etc. I suppose if you're going to do that,
you have to believe it or have a fairly cavalier attitude about
serious injury or death.

The reality is that the warning signs are often subtle or non-existent
until the last few minutes, the instrumentation for monitoring engine
health and performance is often inadequate, the potential for engine
damage by control misuse high in all but the smallest and least
powerful of the engines, and there are an awful lot of unexplained
failures out there. Most of the people I know who have more than 2000
hours in GA have had at least one engine failure.

In my experience, that 1 in 1,000 to 1 in 10,000 number the FAA
provides is right on. It squares with my experience and the
experience of my friends. Also, in my opinion as a practicing
engineer, most of those failures are primarily the result of designs
that are poorly thought out to begin with - perhaps state of the art
by 1940's standards and acceptable by 1960's standards, but now
woefully behind the times. In fact, I would say probably the biggest
factor keeping the failures common is the overly difficult and costly
process that the FAA imposes for adding new technology to these old
beasts.

Michael

In my experience, that 1 in 1,000 to 1 in 10,000 number the FAA
provides is right on. *It squares with my experience and the
experience of my friends.

My primary flight instructor: 4 engine failures in 4500 hours flying.

Dead stick each time. Twice in pattern. Once off airport landing, once
got lucky and managed to glide to a nearby airport.

those are interesting numbers. I went thru our log books. We never had
an engine shut down, but find in what we think is a well maintained
Mooney M20 an unplanned landing about once every 500 hours for some
form of failure. A bank of spark plugs fail, causing the engine to go
rough, a vacuum pump failure, an alternator, things like that. That's
in 3000 hours total time. This airplane is flown gently, though --
wait, maybe not: usually at low RPMs, well leaned, so those 3000 tach
hours understate actual time.

I hope others post their actual experience.



On Apr 1, 10:24*pm, wrote:
In my experience, that 1 in 1,000 to 1 in 10,000 number the FAA
provides is right on. *It squares with my experience and the
experience of my friends.

My primary flight instructor: 4 engine failures in 4500 hours flying.

Dead stick each time. Twice in pattern. Once off airport landing, once
got lucky and managed to glide to a nearby airport.

I must be the exception, in 3700 hours the worst mechanical failure i
have had is the retaining nut coming off of an intake valve
effectively killing one cylinder. Still flew back the airport for a
normal landing.

I don't count the time the throttle cable came disconnected on the
towplane the was pulling me. It didn't come off until after I
released.

Of course about 700 of those 3700 hours are in a gliders (non-self
launch), engine failures are extremely rare in them.

Brian
CFIIG/ASEL

As I said, catastrophic failure can happen, but is the exception in
engine stoppages...

Morning sickness: for example... I can't even begin to estimate the
number of engines I have heard on the ramp, at fly-in's, where ever,
that the engine starts up and shakes like a wet dog for 30 seconds
before it begins to run halfways right - yet these Einsteins just gun
the hell out of it until the valve breaks loose and go take off...

Bad rings: They start up with a big puff of blue smoke, pilot waves,
smiles, puffs out his manly chest and away he goes...

Bad mag: Uncountable times I have heard a run-up where the engine
runs rough on one mag and yet, away they go...

Dripping oil on the ramp: Hot shot pilot just jumps in and off he
goes...

And in hanging around the mechanics shop I am flabbergasted at the
condition of some of the planes brought in:
Mechanic says, 'the plugs are bad, the wires are bad and one is
broken'..
Owner says, 'well, just fix the broken wire I need to be in Pittsburg
today'...

Mechanic said: 'there's a mandatory AD on the fuel servo' (this
happened just last week)
Owner said with a scowl: 'how much is that going to cost?'
Notice that the owner did not ask and did not care what the AD was,
all he focused on was cost... After considerable discussion the
mechanic then said that he could not sign the aircraft out as
airworthy - and stomped off to work on my plane... Owner threw a fit
like a three year old... In the end he agreed to have the AD
performed... The plug on the fuel servo was finger turn loose and
likely would have put the plane into the weeds, sooner rather than
later...
This same engine has 2800 hours smoh and is burning considerable
oil... Owner refuses to overhaul it and if/when it does fail in flight
it wil be another "sudden engine stoppage" (not!)....

denny

"Denny" wrote in message
...

Mechanic said: 'there's a mandatory AD on the fuel servo' (this
happened just last week)
Owner said with a scowl: 'how much is that going to cost?'
Notice that the owner did not ask and did not care what the AD was,
all he focused on was cost...

If it was MANDATORY, the only primary,relevant option would be "when to have
it performed", and that would likely be dictated by "how much it cost".

As for "what the AD was", I suspect many non-mechanic owners wouldn't have
much clue about what it represented. Recall, if you can, Bill Cosby's humor
about what his auto mechanic told him (in "200 MPH")

On Apr 2, 4:34 am, Denny wrote:
As I said, catastrophic failure can happen, but is the exception in
engine stoppages...

Morning sickness: for example... I can't even begin to estimate the
number of engines I have heard on the ramp, at fly-in's, where ever,
that the engine starts up and shakes like a wet dog for 30 seconds
before it begins to run halfways right - yet these Einsteins just gun
the hell out of it until the valve breaks loose and go take off...

Bad rings: They start up with a big puff of blue smoke, pilot waves,
smiles, puffs out his manly chest and away he goes...

Bad mag: Uncountable times I have heard a run-up where the engine
runs rough on one mag and yet, away they go...

Dripping oil on the ramp: Hot shot pilot just jumps in and off he
goes...

And in hanging around the mechanics shop I am flabbergasted at the
condition of some of the planes brought in:
Mechanic says, 'the plugs are bad, the wires are bad and one is
broken'..
Owner says, 'well, just fix the broken wire I need to be in Pittsburg
today'...

Mechanic said: 'there's a mandatory AD on the fuel servo' (this
happened just last week)
Owner said with a scowl: 'how much is that going to cost?'
Notice that the owner did not ask and did not care what the AD was,
all he focused on was cost... After considerable discussion the
mechanic then said that he could not sign the aircraft out as
airworthy - and stomped off to work on my plane... Owner threw a fit
like a three year old... In the end he agreed to have the AD
performed... The plug on the fuel servo was finger turn loose and
likely would have put the plane into the weeds, sooner rather than
later...
This same engine has 2800 hours smoh and is burning considerable
oil... Owner refuses to overhaul it and if/when it does fail in flight
it wil be another "sudden engine stoppage" (not!)....

denny

Got to agree with you, Denny. I've had two engine failures, both on
poorly-maintained engines. Properly-maintained engines are much, much
less inclined to let you down, because the mechanic will find wear or
other developing problems and correct them well before they cause
trouble.
Magnetos are a prime example, and most of them are supposed to
come off every 500 hours and get opened up and inspected. We usually
find that at the 1000-hour mark they need new points and sometimes
other stuff. Sometimes the impulse couple is falling apart. A failed
magneto can do more than just quit: it can start firing at the wrong
time when its internal distributor gears wear out, and really screw
things up. A Bendix dual mag really needs watching, as both mags are
driven by one gear and impulse coupling. Don't know how they ever got
that certified. Those impulse couplings have an AD against them.
Owners are sometimes warned about falling compression. A leaking
exhaust valve is going to burn, and a burning valve head can separate
from its stem and end up in the cylinder. Pistons don't like
compressing valve heads. And engines that sit a lot can get corroded
valve stems; corrosion pits weaken them so they'll break off even if
they're not burning.
Propeller strikes are often ignored. Dangerous, since
crankshafts often acquire cracks just this way.
Engine fluid hoses should get replaced every few years. Oil
cooler hoses get old and hard and can fail in flight, pumping all the
oil overboard. The engine seizes, sometimes in a rather spectacular
manner. Is that the engine's fault?
Once in a great while an engine will fail because of
manufacturing flaws (like a few of Lyc's cranks), but it's really
rare. Most failures are engines that were given the cheapest
maintenance the owners could find.
The pilot is the next big threat to the engine; abusing it, just
like abusing your car's engine, will shorten its life expectancy.
Pushing that throttle open too fast, overboosting, or misusing the
prop control can all do damage. We could built idiot-proof engines,
but they'd be too heavy to fly.

Dan

On 2008-04-03, wrote:
The pilot is the next big threat to the engine; abusing it, just
like abusing your car's engine, will shorten its life expectancy.
Pushing that throttle open too fast, overboosting, or misusing the
prop control can all do damage. We could built idiot-proof engines,
but they'd be too heavy to fly.

No, not really: you could solve many of the pilot-induced problems with
a FADEC. The trouble is, people seem to trust themselves, and are highly
suspicious of a FADEC, even though it's quite likely FADECs fail far
less often than human-induced engine failure.

--
From the sunny Isle of Man.
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