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That_Engine_Guy
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 Posted: Jan 30, 2012 - 12:31 AM
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Elite 2K
Joined: Dec 14, 2005 - 05:03 AM
Posts: 2198
Location: Under the engine somewhere.
Status: Offline
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exfltsafety wrote:
The USAF Viper/PW-229 engine-related Class A mishap rate is 0  But it also had less than 300,000 flight hours as of end of last fiscal year. See http://www.afsc.af.mil/shared/media/document/AFD-080819-035.pdf. The USAF Viper/GE-129 rate was 1 at just under 1 million flight hours.
This is a 'rate' based on 100,000 EFH (Engine Flight Hours) per aircraft loss.
It shows a relationship between how many flight hours are accumulated per engine type versus how many Class-A Mishaps have been caused directly by the engine.
For the F110-GE-129 to have a rate of 1.01 per 100,000 EFH; this equates to 9.9 engines if the fleet has accumulated 990,000 EFH. Doing the math the 1.01 'rate' means that the USAF has lost 10 GE-129 powered Vipers over the course of 990,000 EFH
(If I'm doing the math correctly...) 
Over the last 22 years, the graph is showing the GE-129s are accumulating EFH 3.6x faster than the PW-229s due to sheer USAF numbers. (EFH / 22 years of service)
Accumulating EFH at this pace, the PW-229s will make another 100,000 EFH in 8 years. Likewise the GE-129s will accumulate about 360,000 EFH over the same time frame.
So at the current "rate" from the chart, if the PW-229 Vipers fly 100,000 EFH in 8 years, you could expect the loss of none. (on average based on these statistics)
Also at the current "rate" if the GE-129 Vipers fly 360,000 EFH Hours in those same 8 years, you could predict the loss of 3.6 GE-129 Vipers. (on average based on these statistics)
These are only numbers though, mishap rates tend to go down for engines over their lives until such point as they become too 'tired' especially if they're not funded/maintained properly.
I hope this illustrates why the Mishap "Rate" per 100K EFH is relational between engine types.
Now I need to find a HUGE piece of actual hard wood to knock on; 22 years of Viper PW-229 use and 0 Class-A Mishaps is a HUGE deal.
Keep 'em flyin' 
TEG |
_________________
[Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins
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Sponsor
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 Posted: May 20, 2013 - 3:25 PM
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F-16.net Sponsor
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exfltsafety
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Posted: Jan 30, 2012 - 12:59 AM
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Senior member
Joined: Aug 05, 2009 - 08:11 PM
Posts: 281
Status: Offline
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| TEG - You're right about the 1/100,00 EFH for the GE129. I posted in too much of a hurry. With all the effort that went into engine fixes and improvements over the years, I would hope that the rate/100,000 EFH going forward would be much lower than the cumulative number from the charts. |
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That_Engine_Guy
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Posted: Jan 30, 2012 - 01:21 AM
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Elite 2K
Joined: Dec 14, 2005 - 05:03 AM
Posts: 2198
Location: Under the engine somewhere.
Status: Offline
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exfltsafety wrote:
TEG - You're right about the 1/100,00 EFH for the GE129. I posted in too much of a hurry.
Just wanted everyone to realize the 'rate' was not a 'total'. 
exfltsafety wrote:
With all the effort that went into engine fixes and improvements over the years, I would hope that the rate/100,000 EFH going forward would be much lower than the cumulative number from the charts.
I agree. The GE-129 should do nothing but get better provided CIP funding continues. Hopefully the PW-229 will continue it's top performance and the newer PW-229EEPs will pick and be even more durable from there.
At any rate only 10 engines over the 22 year GE-129 program, covering almost 1 Million flight hours is still out-f'ing standing!
TEG |
_________________
[Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins
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