Service difficulty report · Hmu · Urocop EC130B4

Difficulty date
June 2, 2007
Submitted
July 5, 2007
Operation
General aviation
Aircraft
N151AC
Make and model
Urocop EC130B4
Aircraft serial
3732
Engine
Tmeca ARRIEL2B1
Part
Hmu
Part number
0292858360
Part serial
341B
Condition
Failed
Location
Engine
Part time
1,609 hours
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

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

What was found

THE PILOT REPORTED A LOUD THUD AND A SUBSEQUENT YAWING OF THE AC, WITH CONTINUED YAWING OF THE AC, AND NO INDICATION ON THE COCKPIT INSTRUMENTATION THAT HE NOTICED. THE PILOT DECLARED AN EMERGENCY AND PERFORMED AN AUTORATATIVE LANDING AT THE AIRPORT. THE VEHICLE AND ENGINE MULTIFUNCTION DISPLAY, DISPLAYED FAILURE OF CHANNEL A. THE EC130 IS EQUIPPED WITH A DUAL CHANNEL FADEC SYSTEM WITH A MECHANICAL BACKUP. IN THE FOLLOWING TROUBLESHOOTING PROCESS IT WAS FOUND THAT THE RESOLVER MOTOR ON THE FUEL CONTROL (HMU) HAD A RESISTANCE VALUE THAT WAS OUT OF TOLERANCE. A FIELD TECH WAS BROUGHT IN FROM MFG TO PERFORM FURTHER TESTING, SINCE THE FAILURE OF ONE CHANNEL OF THE FADEC AND THE SUBSEQUENT SWITCHING TO THE OTH

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