B407 Engine Bearing Failures at Low Hours

[November Mike]

Trying to establish if there's a world wide trend, but it seems that the occurrence of bearing failures in the Allison engines in the B407s is more common than not.

I have heard of a number of incidents as of late involving aircraft with 600 to 700 hours on their respective engines.

Anyone with some thoughts as to whether this is cause for alarm? :hmm:

[Bell_ringer]

Haven't heard of any issues locally.
The Allison/Rolls Royce engine hasn't changed with the newer models apart from the compressor improvements.
There is an older SD for the #2 bearing 72-6067, don't have details for it.
The standard gripe seems to be turbine wheels not making their hours but that's about it.

[Chris P Bacon]

There were a batch bearing manufactured with an issue to the rolling portion, causing early metal in oil events. Rolls Royce issue CEB 6075 and as far as I am aware, all but 25 bearings have been removed from service. Check the CEB to see if yours is applicable.

[500guy]

Trying to establish if there's a world wide trend, but it seems that the occurrence of bearing failures in the Allison engines in the B407s is more common than not.

I have heard of a number of incidents as of late involving aircraft with 600 to 700 hours on their respective engines.

Anyone with some thoughts as to whether this is cause for alarm? :hmm:

A friend of mine has one about 2 years ago flying powerline patrol for Duke Energy. It was a Brand new 407GXP with less than 300 hours TTAF. The cause was determined to be the #2 bearing installed incorrectly by RR.

[Heliice]

At some point at around 2013/2014 Rolls Royce said they changed the installation and production method of the bearing. Apparently that has not helped if the same issue has occured in a GXP.

Intersting to see the two different notes from Rolls Royce and Bell. In the Rolls Royce note it states that the malfunctioning bearing is "due to manoeuvres". In the Bell not those words have been deleted.

Cant find the notes at the moment but if you google "Bell 407 bearing failure" you will come up with a lot of stuff.

https://www.bellcustomer.com/files/Storage/IL_407-12-103.pdf

https://www.bellcustomer.com/files/Storage/IL_407-15-110.pdf

B407/RR 250 C47B Bearing Failure [Archive] - PPRuNe Forums (http://www.pprune.org/archive/index.php/t-442673.html)


Oooohh, and that said the 407 is a really nice desk to work at, really miss it !