Service difficulty report · Wire Harness · Boeing 737990ER

Difficulty date
March 10, 2018
Submitted
March 12, 2018
Operation
Air carrier
Aircraft
N413AS
Make and model
Boeing 737990ER
Aircraft serial
35205
Aircraft time
19,946 hours, 6,510 cycles
Part
Wire Harness
Part number
3250434020325043
Condition
Failed
Location
Nr 2 Engine
Stage of operation
IN
How discovered
O
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

WHILE PERFORMING TASK CARD 78273000 FMC CDU FAULT FOUND FAULT CODES 75-20802 T25 SIGNAL DISAGREE SHORT TERM FAULT, 75-10822 T25 IS OUT OF RANGE SHORT TERM FAULT, 75-10802 T25 SIGNAL DISAGREE SHORT TERM FAULT. ALSO ACTIVE UPPER RIGHT EGT FAULT CODE 77-10842 ON ALL FLIGHT LEGS. GROUNDED - YES. PERFORMED A T49.5 PROBE AND EGT SYSTEM INSPECTION PER AMM 77-21-01-200-801-F00. FOUND J9 HARNESS OUT OF RESISTANCE LIMITS TO THE TOP RIGHT EGT PROBE. REPLACED THE J9 HARNESS PER AMM 73-21-06/401. OP-CHECKS GOOD PER SAME. FOUND ACTIVE T25 SENSOR FAULTS 75-10822, 75-10802, AND 75-20802 ON LEGS 2 AND 3. INPUT MONITORING OF THE T25 SENSOR SHOWED DASHES FOR CHANNEL B. INSPECTED THE HARNESS AND FOUND CONNECTOR DP1009 LOOSE. PERFORMED RING OUTS OF THE T25 SENSOR WIRING FOR CHANNELS A AND B REF WDM 77-21-11-1. FOUND AN OPEN CIRCUIT BETWEEN DP1009 PIN 1 AND DP1010 PIN X. REPLACED THE J10 HARNESS PER AMM 73-21-06/401. OP-CHECKS GOOD PER SAME.