SDR UALA2009091602935

Service difficulty report · Relay · Boeing 757222

Difficulty date: September 16, 2009
Submitted: September 17, 2009
Operation: Air carrier
Aircraft: N553UA
Make and model: Boeing 757222
Aircraft serial: 25277
Aircraft time: 57,796 hours, 21,493 cycles
Engine: Pwa PW2037
System (JASC): 3412 · Outside Air Temperature Indicator/Sensor
Part: Relay
Condition: Faulted
Location: Tat Probe
Stage of operation: CL
How discovered: O
Nature of condition: J
Precautionary procedure: A

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

What was found

TAT PROBE EICAS, RTFL. TRIED RELAY K400 IN K410 CURRENT SENSING RELAY POSITION, NO HELP. RE-INSTALLED K400 RELAY IN ORIGINAL POSITION AND PERFORMED RIGHT ANGLE OF ATTACK PROBE HEAT ADJUSTMENT AND TEST, CHECKS GOOD. RE-INSTALLED K410 IN ORIGINAL POSITION, STILL TAT LIGHT ON OVERHEAD PANEL WILL NOT TEST. CHECKED POWER AT CIRCUIT BREAKER R25 FOR TAT PROBE. TAT PROBE DOES NOT HEAT DURING TEST. REPLACED TAT PROBE. ACP'D AFDS TESTS, CHECKS OK. VERIFIED K410 RELAY IS BAD. REPLACED K410. ACP OPS CHECK. CHECKED OKAY.