Service difficulty report · Thermocouple · Boeing 737824

Difficulty date
March 2, 2024
Submitted
March 5, 2024
Operation
Air carrier
Aircraft
N73270
Make and model
Boeing 737824
Aircraft serial
31632
Aircraft time
69,466 hours, 24,363 cycles
Part
Thermocouple
Part number
TC29603
Part serial
DN7422313
Condition
Intermittent
Location
Nr 2 Engine
Part time
455 hours, 188 cycles
Stage of operation
CL
How discovered
O
Nature of condition
M, J
Precautionary procedure
A

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

What was found

RIGHT EGT INDICATION 931 ON CLIMB APROX 15000. RAPIDLY DECREASED TO 890 RAPIDLY DECREASED TO PER DFD 142 REPORT - DURING CLIMB, E2 ESN 874762 HAD AN EGT EXCE EDANCE FOR 143 SECS OVER 895 DEG C WITH A PEAK OF 930 DEG C. PER AMM TASK 71-00-00-800-804-F00, FIGURE 604, THE EXCEEDANCE WOULD BE CLASSIFIED IN "NO ACTION IS NECESSARY." THOUGH WHEN REVIEWIN BASED ON THE TRENDS PLEASE T/S THE EGT SYSTEM USING FIM 77-21-00 -810-805C1. YOU MUST HAVE A POSITIVE FIX (NOT JUST CLEANING CONN ECTORS) BEFORE FURTHER FLIGHT. ALSO, MAKE SURE TO RESET THE EXCE EDANCE WHEN YOU INTERROGATE THE FMCS CDU - REFERENCE AMM TASK 71 NO EXCEEDANCE MESSAGES RECORDED. EEC BITE FAULTED MESS 73-31372 UPPER EGT SECTORS READING HIGH AND 77-20872 TOP LEFT EGT SIGNAL OUT OF RANGE. REPLACED LEFT AND RIGHT UPPER EGT THERMOCOUPLES PER AMM 77-21-01. ENGINE EGT TRENDS THERE IS A DRASTIC SHIFT DOWNWARDS FOR EGT H OT DAY MARGIN (FOR REF ANYTHING BELOW 0 HAS AN INCREASED CHANCE OF AN EGT EXCEEDANCE TO OCCUR DURING TAKEOFF/CLIMB). -00-00-740-801-F00. C/W POWER ASSURANCE RUN. AT HIGH POWER 92% N1, EGT WELL WITHIN LIMITS. NO FLUCTUATIONS AND READING STEADY. AS A PRECAUTION,