Service difficulty report · Mount · Dhav DHC6300

Difficulty date
December 22, 2009
Submitted
January 19, 2010
Operation
General aviation
Make and model
Dhav DHC6300
Aircraft time
31,964 hours
Engine
Pwa PT6A34
Propeller
Hartzl HCB3TN3
System (JASC)
7312 · Fuel Heater
Part
Mount
Condition
Cracked
Location
Fuel Heater
Component
Fuel Heater
Component part number
10552E
Stage of operation
IN
How discovered
V
Nature of condition
O
Precautionary procedure
K

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

What was found

(CAN) DURING AN INDEPENDENT CONTROL CHECK OF THE RT ENGINE, IT WAS NOTED THAT THE OIL TO FUEL HEATER SEEMED LOOSE ON ITS MOUNT. FUEL HEATER WAS REMOVED FROM THE ENGINE AND INSPECTED. BOTH MOUNTING FLANGES OF FUEL HEATER WERE CRACKED. IT IS NOT KNOWN HOW THIS DAMAGE OCCURRED. IT IS POSSIBLE, HOWEVER, TO APPLY A LARGE AMOUNT OF TORQUE ON THE FUEL HEATER MOUNTING FLANGE WHILE INSTALLING FLEXIBLE FUEL LINE ONTO THE FUEL HEATER. THIS FUEL LINE IS REMOVED AND INSTALLED OFTEN TO ALLOW FOR ROUTINE STARTER GENERATOR MIX. IT IS RECOMMENDED THAT FUEL LINE FITTING ON FUEL HEATER BE SUPPORTED BY ANOTHER WRENCH WHEN INSTALLING FLEXIBLE FUEL LINE. SHOULD THE FUEL HEATER BECOME TOTALLY DETACHED FROM THE ENGINE CASE, LOSS OF ENGINE OIL WOULD OCCUR DUE TO THE DISLODGING OF A SMALL PIPE THAT IS SEALED AT BOTH ENDS BY O-RINGS.