Service difficulty report · Wire Harness · Dhav DHC8106

Difficulty date
October 15, 2009
Submitted
December 1, 2009
Operation
General aviation
Make and model
Dhav DHC8106
Aircraft time
33,657 hours
Engine
Pwa PW121
Propeller
Hamstd 14SF7
Part
Wire Harness
Condition
Chafed
Location
Aux Fuel Pump
Part time
34,044 hours
Stage of operation
NR
How discovered
O
Nature of condition
A, B
Precautionary procedure
H

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

What was found

(CAN) DURING TROUBLESHOOTING CONCERNING A FAULTY LT AUX PUMP INDICATION. IT WAS FOUND THAT A WIRING BUNDLE WAS CHAFFED. DURING MAINTENANCE FUNCTION CHECKS OF THE SYSTEM THE WIRE BUNDLE BEGAN TO ARC AND BURN. THIS CAUSED AN IGNITION OF THE VAPORS FROM LPS CONTACT CLEANER USED TO CLEAN THE CANON PLUG ON THE PRESSURE SWITCH. THE RESULTING FLAME EXTINGUISHED ITSELF WITH NO OUTSIDE INTERVENTION. THE CHAFFED WIRING WAS CONTAMINATED WITH DE-ICE FLUID WHICH COATING ALL EQUIPMENT IN THE AREA AROUND THE REAR SPAR AND DE-ICE FLUID ALSO POOLED IN THE LOWER PORTIONS OF THE PANELS. AEROSOL CLEANERS WERE USED TO CLEAN THE AREA PRIOR TO THE FUNCTIONAL TEST. ALL POWER REMOVED, THE AREA VENTED AND THE WIRING BUNDLE REPAIRED WITH NO FURTHER COMPLICATIONS. (TC 20091021012)