Service difficulty report · Wire Harness · Boeing 737990ER

Difficulty date
July 11, 2016
Submitted
July 15, 2016
Operation
Air carrier
Aircraft
N474AS
Make and model
Boeing 737990ER
Aircraft serial
40715
Aircraft time
4,116 hours, 1,366 cycles
Engine
Cfmint CFM567B27E
Part
Wire Harness
Part number
3250434020
Condition
Failed
Location
Nr 2 Engine
Stage of operation
IN
How discovered
V
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

ACQUIRED FAULT CODE ON EEC BITE TEST NR 2 ENGINE. ACFT GROUNDED. FOUND NR 2 ENGINE EEC FAULTS LOGGED 75-10822 IN LEGS 4, 5, 6, 7, AND 10. NO CURRENT FAULTS ARE LOGGED. T25 READING T25 CH B = 21.23, T25 CH A= 21.30. ACCOMPLISHED FIM 75-33 TASK 801. T25 SIGNAL IS OUT OF RANGE, FAULT ISOLATION DISCONNECTED DP0909 AND DP0910. PERFORMED MEASURE THE RESISTANCE BETWEEN THESE CONTACTS TO EXAMINE THE WIRES BETWEEN THE APPLICABLE EEC CONNECTOR, DP0909 (CH A) OR DP1010 (CH B), ON THE WIRE HARNESS THROUGH THE T25 SENSOR: DP0909 PIN M TO PIN L 156 - 339 OHMS. ACTUAL READING IS 216 OHMS. PIN M CONNECTOR SHELL IS MORE THAN 20 MEGOHMS, PIN L CONNECTOR SHELL MORE THAN 20 MEGOHMS. COMPARED TO CHANNEL B AND IT IS READING THE SAME RESISTANCE. MEGGED WIRING AND FOUND NO FAULT ON HARNESS. REINSTALLED ALL DISTURBED ITEMS TO ORIGINAL CONFIGURATION. ACCOMPLISHED NR 2 TASK AMM 73-21-00-700-804-F00, NR 2 EEC TEST, NO FAULTS LOGGED. IAW WDM 75-31-21. REMOVED & REPLACED J-9 & J-10, 3 O'CLOCK STRUT HARNESS ON NR 2 ENGINE IAW AMM 73-21-06-000-802-F00. OPS NORMAL. ACCOMPLISHED FADEC TEST IAW AMM 73-21-00-700-802-F00.