Service difficulty report · Thermocouple · Snias AS350B2

Difficulty date
June 21, 2001
Submitted
June 22, 2001
Operation
General aviation
Aircraft
N5204X
Make and model
Snias AS350B2
Aircraft serial
3099
Aircraft time
802 hours, 1,722 cycles
Engine
Tmeca ARRIEL1D
Engine time
802 hours, 1,143 cycles
Part
Thermocouple
Part number
0301037070
Part serial
6079B
Condition
Out Of Tolerance
Location
Engine
Part time
802 hours, 1,143 cycles
Stage of operation
TX
How discovered
O
Nature of condition
R
Precautionary procedure
E

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

What was found

AIRCRAFT HAD SUFFERED A SERIES OF HUNG STARTS, ENGINE WOULD HANG UP AT 30%. IF THE ENGINE WOULD START, IT WOULD BE A SLOW START. USUALLY, THE PILOT WOULD REACH THE STARTER TIME LIMIT OF 45 SEC'S BEFORE THE ENGINE WOULD START AND BE SELF-SUSTAINING,AND HE WOULD HAVE TO ABORT THE START SEQUENCE. TROUBLE SHOOTING FOUND THE INJECTORS WERE "DRIBBLEING" FUEL INSTEAD OF A SMOOTH,EVEN,FAN PATTERN. CHANGED THE OVERSPEED AND DRAIN VALVE. AFTER HAVING THE SAME RESULTS: SLOW/HUNG STARTS, CALLED A TURBOMECCA TECH REP.HE SUGGESTED THAT WE CHECK THE T4 HARNESS.HARNESS WAS OHMED OUT, ONE PROBE SHOWED AN OPEN PROBE. REPLACED T4 HARNESS, GROUND RUN AIRCRAFT HAD 3 SUCCESSFUL STARTS. OPS CHECK WAS NORMAL. THE SLOW START HUNG START