Why do piston engines fail?

[cburg]

Cross-posted:

 

Why do piston engines fail?

 

http://blog.aopa.org/opinionleaders/2014/04/09/how-do-piston-aircraft-engines-fail/

 

"The bottom line is that a detailed FMEA of piston aircraft engines strongly suggests that the traditional practice of fixed-interval engine overhaul or replacement is unwarranted and counterproductive. A conscientiously applied program of condition monitoring that includes regular oil filter inspection, oil analysis, borescope inspections and digital engine monitor data analysis can yield improved reliability and much reduced expense and downtime.

[Spike]

 

Why do piston engines fail?

 

 

Mine failed due to a labor dispute at Lycoming…… That is, management was pressed into manufacturing positions when the body of the labor force went out on strike. This caused some defective parts to enter into the production streamline. Specifically, mine were the piston-pin caps which worked their way out and begun to rub against the cylinder walls. Eventually, this caused the piston to seize and the connecting rod to fail, at 500AGL…….

Edited April 11, 2014 by Spike

[akscott60]

Mine bend a pushrod because its a mechanical machine that sometimes break. I dont care much other than it gave me a grey hair or two on climbout. At least it didnt fail, just was really sick.

[cburg]

Mine bend a pushrod because its a mechanical machine that sometimes break. I dont care much other than it gave me a grey hair or two on climbout. At least it didnt fail, just was really sick.

Hey VR,

 

Did several projects in Korea...used to eat at the the Kuangju AFB on the way home from the Nuclear plant every evening. Now our company is building drillships in Ulsan.

I guess you’ve been to the Korean war museum in Seoul. I used to take my Korean co-workers at the Chinese shipyard yard in Dalian China to the Chinese Korean War Museum just across the river from North Korea. The cab driver always try to talk you into crossing over, they say it's no problem “mei wenti” BTW nothing is ever a problem. I’m sure it’s no problem getting in…but a big problem getting out;-)

It was hilarious for them to read the Chinese version of the war…propaganda that’s over the top. In northern China they still can’t stop talking about the war with America and how they had to liberate the Koreans from American "capitalist dogs" oppression and unsuccessful attempt to conquer all of the Korean peninsula and mainland China. It’s hilarious…and my normally calm Korean friends get really red-faced.

[cburg]

Hey VR,

 

Did several projects in Korea...used to eat at the the Kuangju AFB on the way home from the Nuclear plant every evening. Now our company is building drillships in Ulsan.

I guess you’ve been to the Korean war museum in Seoul. I used to take my Korean co-workers at the Chinese shipyard yard in Dalian China to the Chinese Korean War Museum just across the river from North Korea. The cab driver always try to talk you into crossing over, they say it's no problem “mei wenti” BTW nothing is ever a problem. I’m sure it’s no problem getting in…but a big problem getting out;-)

It was hilarious for them to read the Chinese version of the war…propaganda that’s over the top. In northern China they still can’t stop talking about the war with America and how they had to liberate the Koreans from American oppression and unsuccessful attempt to conquer all of the Korean peninsula and mainland China. It’s hilarious…and my normally calm Korean friends get really red-faced.

VR,

 

A couple years ago I had a chance to do some trike flying on the beach sort of close to your base...fabulous!

[pilot#476398]

Why do piston engines fail?

 

Because you think you know better than the previous pilot and ignore his reasons for cancelling his flight after only 5 minutes in a hover!

[avbug]

A conscientiously applied program of condition monitoring that includes regular oil filter inspection, oil analysis, borescope inspections and digital engine monitor data analysis can yield improved reliability and much reduced expense and downtime.

 

 

Something we've known for quite some time, and something that those of us who are serious about piston engines continue to religiously practice. TBO means very, very little, and has never been any kind of guarantee.

 

Of the piston failures I've had, the majority have occurred in radial engines. All of those have been mechanical. Other failures in other piston engines have occasionally been mechanical, but more often related to ancillary or support systems, such as a fuel system failure selector, pump, etc). Carburetor ice failures due to very rapid onset have occurred in several horizontally opposed recips.

 

As for the previous poster's comments, if another pilot cancelled his flight and didn't down the aircraft after finding a problem, he needs to be shot. You're suggesting something was written up and other pilots ignored the write-up?

[aeroscout]

Leave an oil cap off or loose and see it that helps a piston engine. It isn't helpful for turbines either.

[avbug]

Leave an oil cap off or loose and see it that helps a piston engine. It isn't helpful for turbines either.

 

 

The last piston engine failure I had was due to complete loss of oil; a brass plug on the bottom of the engine wasn't safetied and came free during a flight following installation of the engine. I saw pressure drop and temp drop at the same time as the oil went out, and that was it.

 

The last turbine failure I had was also loss of oil. Rear turbine bearing seal failed, with a complete oil loss (we drained half a pint after the fact, so perhaps not "complete," but darn near). The manufacturer advised later that the engine has been demonstrated to continue operation for 1/2 hour with no oil. Indeed, mechanically it kept spinning like a top, albeit no oil pressure and no oil temperature. I made to effort to see how long it would go in that condition, and put it on the ground.