Engine Failure Inuvik December 07, 2011

[coffeedrinker]

Does anyone have any idea what happened here? Routine?

From CADORS:

"UPDATE TSB reported that the Kenn Borek Air Ltd. Beech 100, C-FMWM, was operating as Aklak flight AKK 106 from Inuvik, NT (CYEV) to ......, NT (CYPC). When AKK 106 was climbing through 12,000 feet, the flight crew heard a grinding noise, felt a yaw to the left, observed the No. 1 generator light illuminate and observed flames and sparks coming out the No. 1 engine exhaust stack. The flight crew shut down the No. 1 engine (Pratt & Whitney Canada PT6-27A) and performed a single-engine approach and landing back in Inuvik. Company maintenance will report to TSB their findings."

http://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/c ... NN%20BOREK

[ahramin]

Borek's engines are on condition with no TBO, just inspections. MWM eats a stove every couple years - usually on departure around 10 000', no big deal.

[Roar]

Borek's engines are on condition with no TBO, just inspections. MWM eats a stove every couple years - usually on departure around 10 000', no big deal.

I found a statement on the Transport Canada website that claims a PT6 failure rate around 1/200,000hr, so if MWM is regularly having failures one can only surmise that the inspections are not catching problems with the engines or that engines are being run past the point they need to be overhauled. So I disagree with you Ahramin, it is a big deal.

[ahramin]

Sorry Roar, I didn't mean it's no big deal that it eats stoves, I meant it's no big deal when it eats a stove; they're used to it.

Also when you find a statement on a government web site that is germane to the discussion, please feel free to quote it or link to it. Makes the discussion easier. I don't think Borek's failure rates exceed the requirements, TC has people who monitor such things - or used to before SMS anyway. In this case an engine every couple years doesn't mean anything statistically because it's not like they put 2 new engines on it every time an engine fails. They leave the non-failed-yet engine on the plane and put on another non-failed-yet engine from a different plane to replace the did-fail engine.

[Roar]

No need to apologize Ahramin, you are correct the fine crews at Borek do handle emergencies in those old birds with such professionalism as to make it seem like no big deal. All I am trying to say is I am just not a fan of running engines indefinitely beyond TBO. I believe the On Condition program is abused by some in this country, as a way to avoid overhaul costs (thats not a recrimination toward Borek just a general statement).
It would be an interesting stat to see though, what are the failure rates of PT6 engines that are over TBO as opposed to ones under TBO. Anyone out there have that data?

[phillyfan]

I must have missed that part in the letter allowing us to run engines on condition.
"Engines may be run until they seize up and/or burst into flames." "provided that it occurs at an operationally friendly altitude." "If not, remove the engine from the smoking hole and send for overhaul."

[impress]

The only part of this engine that would not be in an O/H condition after hot section inspection and PT inspection would be the compressor and accessory gearbox. This failure does not sound like it was from the back of the engine (compressor), and would not have been prevented by a full engine O/H. The term O/H does not mean something is "new" of "fail-safe" it means it was looked at and checks serviceable to manufacturers OVERHAUL Spec not NEW. If a Turbine wheel with cycles remaining breaks i think it would have nothing to do with On-Condition engine maintenance program.

[ahramin]

Impress, in your opinion is there a difference between a new part, a part with 3000 hours that meets o/h spec, and a part with 10 000 hours that meets o/h spec?

[sidestick stirrer]

Guess I 'll have to dig into the regs to refresh my memory: I thought only private aircraft could operate their engines "on condition"...

[ahramin]

Guess I 'll have to dig into the regs to refresh my memory: I thought only private aircraft could operate their engines "on condition"...

Guess so. There is no more "on condition" for private aircraft.

[kilpicki]

The question is, is there a difference in a new CT blade, one with 3000 hrs and xxx cycles and one with 10,000 hrs and xxxxx cycles, for arguement sake say 20,000 cycles.

jeez for my money I'll go with the new, but hey if it meets oh requirements someone will let it run. or so you say.

[Colonel Sanders]

I'll take 3,000 hours, Alex.

It's less likely to fail than new. See "bathtub curve":

http://www.weibull.com/hotwire/issue22/hottopics22.htm

There is no more "on condition" for private aircraft

To clarify, engine TBO - both TIS and calendar - do not apply to small
privately-owned aircraft. CAR 625, App C(7):

http://www.tc.gc.ca/eng/civilaviation/r ... c-2460.htm

No hard time, including calendar time, between overhauls need be observed in the case of small aircraft reciprocating engines in non-commercial private operation.

and since "on condition" applies to past-TBO ops, hence "on condition"
does not apply to small piston private aircraft as described above.

[Spinner]

Just a guess here but I believe although the engine TBO's are on condition they still have to observe the life limits of the internal components, such as turbine discs, compressor discs etc.

[impress]

Simplified:

early in the thread it was implied that an On Condition engine was less safe, i disagree. Some people think O/H is more safe, i am just stating it does not. Turbine engine components are cycle limited and regardless of engine hours, TBO or On Condition, they come out when they are out of life. No operator can run them more cycles than any other. Just highlighting the false perception that O/H is any safer or on condition is less safe because they all have the same parts. I do not know of many (or any) operator can put new turbine engines in their aircraft as in most cases 1 engine would exceed the value of the aircraft on which they are being installed. (ie King Air 100 or any other small twin turbine)

[Doc]

On the subject of the high cost of engines, vs. airframes. Whatever happened to the Orenda V8 project of a few years back? Replacing PT6's with V8's. Seemed a good idea, but it never got off the ground.

[Valkyrie_XB70]

I seem to recall they couldn't get the reliability out of them that was required for certification. But don't quote me on that.

[Colonel Sanders]

high cost of engines, vs. airframes

I find this fascinating:

http://www.stolairus.com/product/WALT001

But then again, many people think I am in dire need of adult supervision.

[Canoehead]

I just bought two. Hope they don't have a BOGO sale anytime soon or I'll be ticked