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Likelihood of engine failure


toto

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It is hard to get data on GA engine failure rates.  I’ve tried, using FAA data on GA hours flown (a careful guess) and engine failures reported (under-reported legally and otherwise) and at best you can get an order of magnitude statistical answer.  

As far as I could derive: Small flat four cylinder NA engine failure rates are in the one per 10,000 hour range—not that exact number but on that order of magnitude.  

The 300 + hp turbocharged six cylinder engines are about 3 times worse, based on PA46 fleet data.   

I suppose it makes sense that manufacturers who probably have the best (not necessarily good, but still the best) data don’t want to publish for several reasons.  

The part 121 operations can tell you what their failure rates are.  They collect their own data on every engine hour.   Big fan jet engines run hours daily so not relevant to us.  

The airline industry does publish data in fatalities per 100 million passenger miles.   That can be compared to GA with some calculations and a few assumptions.  In those terms, piston GA is somewhat better than motorcycles, passenger cars 2-10 times better than GA, and airliners two orders of magnitude better than cars.  

Pratt & Whitney Canada claim the “uncommanded shut down rate” for the PT6A turboprop series is about 1 per 300,000 engine hours. Even that neat figure needs massaging to include engines that clearly were about to fail but were shut down by the pilot.   Still it is 1 to 2 orders better (10 to 100 times better) than GA piston.  

The late Richard Collins returned to the subject of engine failure again and again in the decades he wrote about GA.   Try as he did he never got much better than order of magnitude approximations.   So he focused in on relative rates. 

For example, he early pointed out that GA twins were, probably still are, less safe per hour than GA single engine craft.  The difference was small, but statistically valid.  

This thread’s poll is interesting but out of context it’ is nearly meaningless.  

Yeah, I’ve had a failure or two — Most serious was a turbocharger failure that dumped out the engine oil.   One in 2,200 piston hours. Well that’s about average.  But proof by example is no proof.  

In the pursuit of safety it is too bad we don’t have better data to drive our choices and guide our training.  

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22 hours ago, Mooneymite said:

Partial power loss can lull one into making a bad decision about continuing to the airport.

A neighbor died when his Stearman began sputtering right after takeoff.  Rather than land straight ahead with the engine still running, he elected to turn downwind and got into the stall spin scenario....

A tough call to make when you have partial power.

AOPA just posted this...

This could have ended up as a stall/spin had he not made that last minute decision to land off airport.

 

Edited by Tony Starke
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4 hours ago, Jerry 5TJ said:

It is hard to get data on GA engine failure rates.  I’ve tried, using FAA data on GA hours flown (a careful guess) and engine failures reported (under-reported legally and otherwise) and at best you can get an order of magnitude statistical answer.  

As far as I could derive: Small flat four cylinder NA engine failure rates are in the one per 10,000 hour range—not that exact number but on that order of magnitude.  

The 300 + hp turbocharged six cylinder engines are about 3 times worse, based on PA46 fleet data.   

I suppose it makes sense that manufacturers who probably have the best (not necessarily good, but still the best) data don’t want to publish for several reasons.  

The part 121 operations can tell you what their failure rates are.  They collect their own data on every engine hour.   Big fan jet engines run hours daily so not relevant to us.  

The airline industry does publish data in fatalities per 100 million passenger miles.   That can be compared to GA with some calculations and a few assumptions.  In those terms, piston GA is somewhat better than motorcycles, passenger cars 2-10 times better than GA, and airliners two orders of magnitude better than cars.  

Pratt & Whitney Canada claim the “uncommanded shut down rate” for the PT6A turboprop series is about 1 per 300,000 engine hours. Even that neat figure needs massaging to include engines that clearly were about to fail but were shut down by the pilot.   Still it is 1 to 2 orders better (10 to 100 times better) than GA piston.  

The late Richard Collins returned to the subject of engine failure again and again in the decades he wrote about GA.   Try as he did he never got much better than order of magnitude approximations.   So he focused in on relative rates. 

For example, he early pointed out that GA twins were, probably still are, less safe per hour than GA single engine craft.  The difference was small, but statistically valid.  

This thread’s poll is interesting but out of context it’ is nearly meaningless.  

Yeah, I’ve had a failure or two — Most serious was a turbocharger failure that dumped out the engine oil.   One in 2,200 piston hours. Well that’s about average.  But proof by example is no proof.  

In the pursuit of safety it is too bad we don’t have better data to drive our choices and guide our training.  

Those are the right comments and questions Jerry.   Thank you.  In the end of the day, its not about the engine alone.  Its about the safety statistics of the activity.  I did some research about 10 years ago and came up with roughly as you did. GA is a little better than motorcycles and a little worse than cars.  But in context, other activities that I do are comparable, that many people don't blink at.   Most notably bicycles are not so great from an actuarial statistics standpoint.  Most people don't know - but canoes are quite bad - and I live on a lovely lake and I often canoe or flat water kayak.  So serene...but...

I had not seen anything leading to your report that flat 4's might have a failure mean rate of 1 per 10,000hrs vs 3 times worse for 300hp flat 6's.  That's roughly 1 per 3,000 which is quite sobering.

Nonetheless, I don't find this thread to be useless since it makes us think and thinking pilots are better pilots on a whole.  Thinking about what if...then embeds a course of action in our brains IF it really happens.

Ye old twin vs single debate...lest this thread spin off into that direction - two thoughts - there is a reason twins are more expensive to insure than singles, for same hull value, and insurance company actuaries know their business.

Food for thought - I found out when I was buying my current airplane about ten years ago, that a former owner of it, who owned it for 20 years or so, died one day stepping out of his car, in a car-pedestrian accident.  Stepping out of your car on the traffic side of the street after parallel parking is actually a very risky maneuver that we are so used to we may forget - I actually think of him every time I check my rear view mirror before I open my door.  The airplane didn't get him.  Standing up out of his car seat did.  Very tragic.

Edited by aviatoreb
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37 minutes ago, Tony Starke said:

AOPA just posted this...

This could have ended up as a stall/spin had he not made that last minute decision to land off airport.

 

This is a superb video.  I think visualizing and thinking of such things helps pattern it into our brains so that if..it happens we are ready to make exactly those decisions as necessary.

I have been thinking lately that maybe since I made a successful on airport runway landing a few weeks ago, that perhaps I would be more susceptible to a bad accident if I ever had an engine failure again, trying to repeat my success when the situation might call for an off airport landing in a different situation.  SO I am glad to view this video.

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9 hours ago, Jerry 5TJ said:

It is hard to get data on GA engine failure rates.  I’ve tried, using FAA data on GA hours flown (a careful guess) and engine failures reported (under-reported legally and otherwise) and at best you can get an order of magnitude statistical answer.  

 

None of my engine failures were ever reported in a forum you would find. The last one was a full FSDO investigation that concluded it wasn't caused by missing a gear rigging AD or missing a seat belt placard. Called them up a month later to ask for a copy of the finding so I could send it to Lycoming (950 SFNEW) and they told me to file a FOIA request. Did that and they said they shredded the findings because there was no administrative action taken against me.

So I don't know how you could ever find a database on the number of engine failures.

-Robert

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4 minutes ago, RobertGary1 said:

None of my engine failures were ever reported in a forum you would find. The last one was a full FSDO investigation that concluded it wasn't caused by missing a gear rigging AD or missing a seat belt placard. Called them up a month later to ask for a copy of the finding so I could send it to Lycoming (950 SFNEW) and they told me to file a FOIA request. Did that and they said they shredded the findings because there was no administrative action taken against me.

So I don't know how you could ever find a database on the number of engine failures.

-Robert

I found both fists clinched after reading this...

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This poll reminds me of the motorcycle question "ever crashed?"  It all boils down to if you live you will take risks try to take calculated risks that are more than dumb luck.   I worry about power loss all the time and I've had experienced it first hand in my new to me Mooney.   I was I lucky I was in pattern and all that kept going thru my little brain was fly the plane and worry about the rest later.  I was abeam the numbers I was altitude ok but Mooney green and I freaked inside.  Fuel servo was the problem but had I panicked I think it could have ended really bad.   

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I've had three events that I'd consider engine failure; two were complete power losses and one was a partial due to a clogged injector.   The clogged injector happened early in climb-out just as the end of the runway was disappearing under the nose.   I told the tower I had power loss, struggled around the pattern (it was climbing, but slowly), and was met at my hangar by a very polite guy from the city who wanted my name, etc.   A couple of weeks later I got a call from the FSDO which was just a short conversation about what happened, etc., that resulted in no action.

Both of the complete power loss failures also resulted in on-airport landings (thankfully), but never got reported anywhere afaik, even though one was at a towered field (but I just landed without making any kind of declarations, I was kinda busy).   I think the lack of declaration made it somehow less "reportable", as the city guy did not meet me at the hangar that time.   

So, yeah, I don't think there is any way to get statistics that are accurate to better than an order of magnitude or so, which isn't very useful, unfortunately.

 

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Some companies still operate substantial fleets of airplanes flying our engines.  For example I know that Cape Air still flies a pretty good sized fleet of Cessna 402 each  sporting a pair of TSIO520VB engines.   I bet they keep statistics on their own fleet.  Sure there are differences from owner operated airplanes but still it could give a good idea in a relatively controlled environment.  Across I bet 30 or 40 airplanes and maybe 60 to 80 or more engines.

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I lost mine at 200ft leaving an MSC. Don't think that having the best names in your logbooks will prevent you from having any sort of failure. There is inherent risk that you are taking with flying piston single engine airplanes. 

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13 hours ago, Tony Starke said:

AOPA just posted this...

This could have ended up as a stall/spin had he not made that last minute decision to land off airport.

 

 

So much in this was similar to my experience. The only difference was that I immediately killed my engine once it quit as I was low and there was a field directly ahead of me (with a neighborhood behind it), and I threw the gear down because I needed the drag to slow down to make the field. The pilot did the same thing I did when I stopped too. I called the tower and said that we were ok and started to turn switches off. After the first three switches, I say to my passenger, "We need to get out of this" because at that point I realized that there could be fuel leaking and we could have a post-impact fire. The pilot of this P51 allowed himself to be at that same risk. 

This brings me to another point regarding warbirds. You were the cream of the cream if you were flying those aircraft when they were brand new; there were operational losses that are acceptable in times of war that are unacceptable in times of peace; and they typically were operated and maneuvered at higher altitudes than would be visible from spectators at airshows. Now the fleet is over 70 years old piloted by people who are lucky to have experienced anecdotes from those originally selected by rigorous means from the largest pool of applicants in history. 

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16 minutes ago, Antares said:

I lost mine at 200ft leaving an MSC. Don't think that having the best names in your logbooks will prevent you from having any sort of failure. There is inherent risk that you are taking with flying piston single engine airplanes. 

That’s not very comforting. What were you there for? Engine work, annual?

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14 minutes ago, Tony Starke said:

That’s not very comforting. What were you there for? Engine work, annual?

Alternator failed on my way to Las Vegas; MSC was close by so I stopped in and had it repaired. It ended up being a bad wire. On initial climb-out FOD went through the #4 cylinder. 

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1 hour ago, Antares said:

Alternator failed on my way to Las Vegas; MSC was close by so I stopped in and had it repaired. It ended up being a bad wire. On initial climb-out FOD went through the #4 cylinder. 

Glad you and your passenger made it out of that one alive. Did you ever find out what the FOD consisted of?

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10 minutes ago, Tony Starke said:

Glad you and your passenger made it out of that one alive. Did you ever find out what the FOD consisted of?

No. The shop recovered the airplane, removed the cylinder and refused to give me access to the parts or photographs of the parts. 

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18 hours ago, Tony Starke said:

AOPA just posted this...

This could have ended up as a stall/spin had he not made that last minute decision to land off airport.

 

Thanks for posting this. Well worth a watch. 

I noticed that there is also a long-form version of this video with a full pilot interview. Pretty great stuff. 

 

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4 hours ago, Antares said:

No. The shop recovered the airplane, removed the cylinder and refused to give me access to the parts or photographs of the parts. 

Makes me really nervous for people to work on my plane without my supervision. If I had to use a shop while away from home I’d really push to be there and watch them. You may be paying $120/hr but some of those guys arent pulling $20/hr that touch your plane  

-Robet

Edited by RobertGary1
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Well....

What we know enough about...

1) We got input from a few people that have experienced many engine challenges in total...

2) Some of the input came from people strong in statistics, maintenance, and/or piloting planes...

3) We recognize the short comings of polls and other statistically flawed data collections...

 

What we got out of this flawed poll...

1) The opportunity to discuss how this flawed poll relates to our flying experience...

2) We know that at least once in our Mooney flying experience, we are going to have the displeasure of a serious engine problem after the plane has left the ground...

2a) Had my first partial power loss experience, in my first 10hours of Mooney time...

2b) There must be a statistical reference for why having an experience already doesn’t preclude having another one tomorrow... or next week... or next...

3) it is not remote enough to ignore...

4) it is common enough...

  • we equip for it. engine monitors, CO monitors, shoulder harnesses...
  • we train for it. Power off landings from the traffic pattern...
  • we strategize for it.  Land straight ahead...  know where the first potential landing sites are for each take-off...
  • we discuss it openly...

5) It not what we start that’s important... it is what we finish...

that’s what we get measured by, that’s what counts...  :)

6) Plan to finish, finish the plan...

7) Finish Strong!

8) Use the checklist... power out checklists are memorized... for a reason.  They are often a left to right, top to bottom flow...

9) first thing on the checklist... lower the nose immediately don’t allow the plane to slow into a stall...

10) Mooney/ MSer pilots have statistically fared better slowing to land level in trees, before trees, in city streets, open fields... Then they have fared executing the impossible turn...  (statistically probably isn’t the right word...)   :)

 

There is no prize for not flying as far into the accident as possible... Never give up!

PP thoughts only... not a CFI or statistician...

Keep thinking, sharing your thoughts... go MS!

Best regards,

-a-

 

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3 hours ago, RobertGary1 said:

Makes me really nervous for people to work on my plane without my supervision. If I had to use a shop while away from home I’d really push to be there and watch them. You may be paying $120/hr but some of those guys arent pulling $20/hr that touch your plane  

-Robet

I’m with you RobertGary1, I have friends that drop their planes off at the “big name” shops for maintenance and annuals, then pick them up and fly away without a second thought. I have a mechanic that allows me to work beside him and make decisions as a team.  There are often more than a few guys working under that big name and I wouldn’t doubt that the guy with the name might not ever set eyes on your plane. 

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Good video and I don’t take anything away from the pilot, but man he was gifted with suitable surrounding fields that are not always there in that situation.

10 years ago I had a sudden and complete engine failure in cruise over hostile terrain. Due to the Mooney’s excellent gliding capability, I was able to glide clear of the terrain and into a good paddock with height to spare. Doubt if I would’ve made it into the paddock in a Bo or 210.

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20 hours ago, Tony Starke said:

I’m with you RobertGary1, I have friends that drop their planes off at the “big name” shops for maintenance and annuals, then pick them up and fly away without a second thought. I have a mechanic that allows me to work beside him and make decisions as a team.  There are often more than a few guys working under that big name and I wouldn’t doubt that the guy with the name might not ever set eyes on your plane. 

In my younger days I did the drop off at Mooney service centers. I found I had to reinspect the plane afterwards. I found. 

No cotter pin on wheel bearing ( wheel could fall off)

no nut on the aileron bellcrank after replacement. 

Bolt securing tail hing too short so nut only had 1/2 threads. 

Antennas not hooked up 

battery connected backwards 

log entry not done for annual 

5 hours labor charged for one mechanic when the plane was only there 3. 

Tow bar missing 

others things that escape me now 

if it’s your butt crossing the sea of Cortez in Mexico outside gliding range you want to make sure Work is right. 

-Robert 

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  • 1 month later...

So I've seen the fuel servo mentioned a couple of times in this thread, and that looks to have been what brought us down on Sunday. Is there a way to prevent such failures in flight? This plane was in annual, had been well tended to, and actually had a rebuilt fuel servo installed a couple of years ago... 

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30 minutes ago, chrixxer said:

So I've seen the fuel servo mentioned a couple of times in this thread, and that looks to have been what brought us down on Sunday. Is there a way to prevent such failures in flight? This plane was in annual, had been well tended to, and actually had a rebuilt fuel servo installed a couple of years ago... 

The exact same comments would apply to N1310W, the 64E that was totaled in 2012.  The NTBS found a small piece of torn o-ring had blocked flow in my fuel servo.  The event occurred 130 flight hours and 25 months after the fuel servo R&R.
 

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48 minutes ago, neilpilot said:

The exact same comments would apply to N1310W, the 64E that was totaled in 2012.  The NTBS found a small piece of torn o-ring had blocked flow in my fuel servo.  The event occurred 130 flight hours and 25 months after the fuel servo R&R.
 

Yeah, that too got me worried about it. And the fact that the A&Ps I've talked to all zeroed in on the servo being the likely culprit. Seems to be a "not unusual" point of failure. Is there anything we can do to guard against such issues? Have it checked every annual / 100 hour? Any pre-flight checks that can be done (unlikely to be anything feasible)?

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