What a tremendous milestone for Pratt & Whitney!

https://newsroom.prattwhitney.com/2023- ... Innovation

I thought this was interesting in the news feed. Certification in some countries like Canada asked for very detailed info on inflight shutdowns and mean time between failures. The PT6 may be the most reliable engine in service? At least 650,000 hours mean time between failure.

The PT6 is also the only turboprop engine in the world to be approved for single-engine instrument flight rules (SEIFR) in commercial passenger flights in Europe, North America, New Zealand and Australia.

Absolutely incredible engines. At Metro Airlines we had them on our Twin Otters and we were getting 9000 hours between overhaul. Amazing engines.

The definition of "failure" is heavily in Pratt's favor. They don't count things like fuel controllers, pumps, governors, etc. Just the "core" engine. When looking at engine failure, the majority come from other stuff. This paper says only 14% of PT6 failures are the "core" engine, the rest are controls and accessories, fuel/oil systems, and "other".

http://www.tc.faa.gov/its/worldpac/techrpt/ct92-29.pdf

It doesn't really matter to the pilot why the engine failed, they still have to deal with it.

The 650,000 hour figure seems bogus to me on its face as well. Seems to come from this:

"The Pratt & Whitney Canada PT6 is known for its reliability with an in-flight shutdown rate of one per 333,333 hours from 1963 to 2016,[5] lowering to one per 651,126 hours over 12 months in 2016."

Nice cherry pick of a specific 12 month period! I seriously doubt 2016 engines were mechanically different enough to be half the failure rate of the prior year.

To say it another way, 1 billion flight hours and 650,000 hours between failures means there have been about 1500 engine failures, or about 2 per month. Of course, not all of those billion hours, perhaps hardly any, are PT6. Most of the hours are going to be airliner engines.

Mike C.

Well, according to the news release, they said PT6s accounted for over 500 million hours since 1963. That seems to me to be 50% of 1 billion…



BWTHDIK…

For reporting Pratt has to keep a record of every in flight shutdown regardless of reason. Most of those occur in twins, and many would not be a shutdown in a single, such as a faulty sensor. Those numbers are still very good.

The 1 Billion number is all engines since 1928, right in the press release

I asked a few of my former PW colleagues about this.

The numbers quoted are only Pratt & Whitney Canada engine hours (all models back to day one). PT6 models account for about 1/2 of the total.

Large commercial engines (manufactured in the US) are well over a billion also.

Art

The definition of "failure" is heavily in Pratt's favor. They don't count things like fuel controllers, pumps, governors, etc. Just the "core" engine. When looking at engine failure, the majority come from other stuff. This paper says only 14% of PT6 failures are the "core" engine, the rest are controls and accessories, fuel/oil systems, and "other".

http://www.tc.faa.gov/its/worldpac/techrpt/ct92-29.pdf

It doesn't really matter to the pilot why the engine failed, they still have to deal with it.

The 650,000 hour figure seems bogus to me on its face as well. Seems to come from this:

"The Pratt & Whitney Canada PT6 is known for its reliability with an in-flight shutdown rate of one per 333,333 hours from 1963 to 2016,[5] lowering to one per 651,126 hours over 12 months in 2016."

Nice cherry pick of a specific 12 month period! I seriously doubt 2016 engines were mechanically different enough to be half the failure rate of the prior year.

To say it another way, 1 billion flight hours and 650,000 hours between failures means there have been about 1500 engine failures, or about 2 per month. Of course, not all of those billion hours, perhaps hardly any, are PT6. Most of the hours are going to be airliner engines.

Mike C.

I think Pratt knows about most failures since if it is a failure in workmanship they have been known to inspect the parts and replace them even out of warranty. They have aggressive process improvement and seek to remedy problems. Not really like the piston manufacturers. Their reputation and support sells very expensive engines. They don’t want failures. The last data I saw was still about 650K MTBF and the all inflight shut downs IFSD were also quite impressive. They track IFSD causes as well and seek to mitigate those as possible, but often lie with the airframer.

At Cessna we had a captive fleet in the T-47 program. I got the shutdowns, removals, etc., from the maintenance people and it was very different (higher) than what PWC was reporting.

Is there are database you can check to see if your engine shutdown is included?

None that I knew about that was accessible to the operator or public. Some may be on FAA or NTSB databases if they were reported to FAA or NTSB. I might be out of date, though.

The definition of "failure" is heavily in Pratt's favor. They don't count things like fuel controllers, pumps, governors, etc. Just the "core" engine. When looking at engine failure, the majority come from other stuff. This paper says only 14% of PT6 failures are the "core" engine, the rest are controls and accessories, fuel/oil systems, and "other".

http://www.tc.faa.gov/its/worldpac/techrpt/ct92-29.pdf

It doesn't really matter to the pilot why the engine failed, they still have to deal with it.

The 650,000 hour figure seems bogus to me on its face as well. Seems to come from this:

"The Pratt & Whitney Canada PT6 is known for its reliability with an in-flight shutdown rate of one per 333,333 hours from 1963 to 2016,[5] lowering to one per 651,126 hours over 12 months in 2016."

Nice cherry pick of a specific 12 month period! I seriously doubt 2016 engines were mechanically different enough to be half the failure rate of the prior year.

To say it another way, 1 billion flight hours and 650,000 hours between failures means there have been about 1500 engine failures, or about 2 per month. Of course, not all of those billion hours, perhaps hardly any, are PT6. Most of the hours are going to be airliner engines.

Mike C.

How do other engine manufacturers do it? If they all do it the same way, then the results are comparable.