SDR 95ZZZM457

Service difficulty report · Relay · Dhav DHC6300

Difficulty date
July 20, 1995
Submitted
March 26, 2000
Operation
Air carrier
Aircraft
N28SP
Make and model
Dhav DHC6300
Aircraft serial
601
Part
Relay
Condition
Failed
Location
Lt Starter/Gen
Component
A701AD
Stage of operation
IN
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

LEFT REVERSE CURRENT CUTOUT RELAY MAIN CONTACTORS REMAINED CLOSED AFTER ENGINE SHUTDOWN CAUSING THE STARTER/GENERATOR TO MOTOR CONTINOUSLY UNTIL THE MOTOR WAS DAMAGED FROM EXCESSIVE HEAT. THE LEFT ENGINE STARTER/GENERATOR AND REVERSE CURRENT CUTOUT RELAY WERE BOTH REPLACED. POST INSPECTION OF CUTOUT RELAY REVEALED THAT THE MAIN CONTACTORS WERE NOT BURNED AND FUSED. HOWEVER, THE 'E' TYPE EXTERNAL RETAINING SNAP RING THAT SECURES THE MAIN MOVEABLE CONTACTS ASSEMBLY WAS FOUND BROKEN. THUS ALLOWING THE MAIN CONTACTS TO CONNECT WITH THE STATIONARY CONTACTS. THIS PROVIDED CONTINUOUS POWER TO THE STARTER/GENERATOR, DAMAGING IT.