Service difficulty report · Timing Chain · Diamon DA42NG

Difficulty date
December 2, 2016
Submitted
December 2, 2016
Operation
General aviation
Aircraft
N455AM
Make and model
Diamon DA42NG
Aircraft serial
42AC119
Aircraft time
2,758 hours
Engine
Austro E4
Engine time
1,723 hours
Propeller
Mtprop MTV6R
Part
Timing Chain
Part number
E4A75100000
Condition
Failed
Location
Lt Engine
Part time
1,723 hours
Stage of operation
CR
How discovered
O
Nature of condition
R, J
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

DURING CRUISE BACK FROM A CROSS COUNTRY. THE LEFT ENGINE LOST POWER TO 30% LOAD. STARTED THEIR DECENT FOR PROVO AIRPORT. AFTER LANDING THE PROPELLER STOPPED ROTATING. THE AIRCRAFT WAS PULLED IN THE NEXT MORNING AND IT WAS DETERMINED THAT THE TIMING CHAIN HAD FAILED. IT WAS VERIFIED BY ROTATING THE PROPELLER WITH THE HIGH PRESSURE PUMP REMOVED AND THE CAM SENSOR COVER REMOVED TO SEE IF THE CAMS WERE ROTATING WITH THE CRANK. AFTER FURTHER INVESTIGATION THE HEAD OF THE ENGINE WAS REMOVED AND WE FOUND THE TIMING CHAIN HAD FAILED AT A LINKAGE POINT. OTHER DAMAGE FOUND WAS MARKS ON THE PISTONS OF VALVE IMPACT AND LIFTERS WERE ALL BROKEN. AUSTRO ENGINE IS TALKING ABOUT MAKING A 900 HR TIMING CHAIN REPLACEMENT. ACCORDING TO THEM THIS IS THE 4TH TIMING CHAIN THAT HAS FAILED IN FLIGHT.

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