Service difficulty report · Warning Light · Amd FALCON50MYST

Difficulty date
February 21, 2017
Submitted
February 21, 2017
Operation
General aviation
Aircraft
N733M
Make and model
Amd FALCON50MYST
Aircraft serial
343
Aircraft time
3,997 hours, 2,374 cycles
Part
Warning Light
Condition
False Activation
Stage of operation
TX
How discovered
O
Nature of condition
N
Precautionary procedure
O

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

What was found

DURING START SEQUENCE, WHILE STARTING THE NR 1 ENGNE, BATTERY 1 AND 2 LIGHTS CAME ON AND STAYED ON AFTER ENGINE FINISHED START. ( RELAYS STAYED OPEN). ALL THREE ENGINES RUNNING WITH BATTERY 1 AND 2 LIGHTS ON. BATTERY SWITCHES DID NOT TRIP. DEPRESSED EXTERNAL POWER PUSHBUTTON AND RELEASED IT, BATTERY 1 AND 2 LIGHTS WENT OUT. REPLACED GCU'S, PROBLEM REMAINED, REPLACED RELAY 123P AND CIRCUIT BOARD 42P, PROBLEM REMAINED. REPLACED CONNECTOR 10P, PROBLEM REMAINED. BELIEVE HIGH RESISTANCE IN START SWITCHES ARE CAUSING INTERMITTENT PROBLEM. FROM 12JN GROUND THRU START 1 THRU START 2 THRU START 3 THRU APU START/STOP THRU GPU START THRU POWER CONTACTOR THRU 123P RELAY