Service difficulty report · Generator · Dhav DHC8*

Difficulty date
October 12, 2009
Submitted
October 27, 2009
Operation
General aviation
Make and model
Dhav DHC8*
Part
Generator
Part number
11522185
Part serial
115221800385
Condition
Overheated
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

GENERATOR OVERHEATED. ENGINEERING HAS IDENTIFIED A SECOND DEFECTIVE WELD IN A MAIN ROTOR BAND (643104-1) THAT PROPAGATED TO A FAILURE CONDITION RESULTING IN A GENERATOR FAILURE IN SERVICE. THE WELD APPEARS TO SHOW STRONG INDICATIONS OF INCOMPLETE FUSION (ORIGINAL UNMELTED JOINT SURFACE) ALONG THE ID SIDE OF THE WELD. THE INCOMPLETE FUSION ZONE BEGINS ON ONE END OF THE WELD AT ALMOST 50 PERCENT OF THE THICKNESS AND TAPERS TO NEARLY -0- PERCENT (FULLY WELDED) ON THE OTHER END.