Service difficulty report · Resistor · Cessna 340A

Difficulty date
November 30, 2007
Submitted
December 18, 2008
Operation
General aviation
Make and model
Cessna 340A
Aircraft time
5,411 hours
Engine
Cont TSIO520NB
Propeller
Mcauly 3AF32C505
Part
Resistor
Part number
OR551
Condition
Overheated
Location
Heater Blower
Stage of operation
CR
How discovered
O
Nature of condition
B
Precautionary procedure
B

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

What was found

(CAN) RESISTOR LOCATED UNDER CO-PILOT SEAT(CONTROLS HIGH LOW OPERATION OF HEATER BLOWER MOTOR. THERE ARE 3 RESISTORS OF THE SAME TYPE IN THIS LOCATION, IN THIS CASE HEATER RESISTOR-OR55-1 OVERHEATED CAUSING THE TY-RAP LOCATED ON THE UPPER PORTION OF RESISTOR TO MELT AND CATCH FIRE, THERE IS A SMALL SHIELD OF FLAME RESISTANCE MATERIAL ON THIS TERMIAL WHICH THE TY-RAP KEEPS IN PLACE. RECOMMEND THIS AREA BE CHECK TO THE HEAT BUILD UP OF THIS RESISTOR AS THIS WILL INDIACATE THE NEED TO BE CHANGED. RESISTOR WAS CHANGED AND THE NEW RESISTOR HL55-08-Z-1-OHM WAS FOUND AFTER A 30 MINUTE RUN THE TEMP WAS 123 FDEGREES AND THE OLD RESISTOR WAS 187F DEGRESS IN FREE AIR WITH THE SAME LOAD FACTOR,IN THE ENCLOSED SPACE I ASSUME THE TEMP WOULD RISE MORE THAN THAT,MUST ALSO BE NOTED A COMPLETE HAD BEEN INSTALLED ABOUT 77HRS PIOR TO THIS.

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