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Oil Exhaustion and Engine Failure - Check your oil pressure valve bolt!

  • dpralle
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3 weeks 5 days ago #21919 by dpralle
I am the partial owner of a VANS RV-12 factory built SLA with a Rotax 912ULS engine. Last Saturday, we experienced a total in-flight engine failure due to oil exhaustion. Luckily, the pilot was close to the airport, kept his wits about him, and was able to dead stick the airplane back onto the runway.

Upon inspection, the bolt in the bottom of the oil pump that secures the oil pressure valve was found to have backed out of the oil pump. Once the bolt fell out, the engine ran for approximately six minutes before all oil was pumped out of the sump and the engine seized.

Given that this bolt is rarely, if ever, removed during service, and there is no Rotax requirement or recommendation to check the torque or presence of safety wire as part of an oil change, 100 hour, or annual inspection, it can be easily overlooked.

I highly recommend checking your engine immediately to ensure that this bolt is properly secured/safety wired and rechecking at each oil/filter change. Doing so at a minimum may save you from writing a $18k check for a new motor and ultimately may save a life.

It was pure chance that the pilot was close enough to the airport to perform a dead stick landing on the runway. An off airport arrival may not have been as successful.

The images below show the location of the bolt, the bolt as found, and the point on the engine where the bolt should have been safety wired.



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The following user(s) said Thank You: zanzark

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3 weeks 4 days ago - 3 weeks 4 days ago #21924 by Roger Lee
You are right that at least the mechanic doing the annual should look for safety wire presence.

This oil pressure plug screw, the magnetic oil plug and the oil tank plug are supposed to be safety wired in place. I do have them come in from time to time where this wasn't done.
The oil pressure plug screw torque should be 133 in/lbs.

Heavy Maint. manual Rev. 4 (newest one) section 79-00-00 page 18 paragraph 3.1.4. It specifies torque and safety wire.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last edit: 3 weeks 4 days ago by Roger Lee.

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3 weeks 4 days ago #21926 by dpralle
Roger,

You’re absolutely correct that it should be safetied, but the fact that it’s on the bottom of the motor and isn’t a bolt that is normally touched during normal maintenance means that even someone familiar with Rotax engines is likely to miss it.

In this case, the engine was 20 hours removed from a thorough annual where other discrepancies were caught and rectified.

Maybe this is a one off, but it’s painful nonetheless.

Darren

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3 weeks 4 days ago #21928 by Roger Lee
I'm sorry to hear and yes it was very unfortunate.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

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