Service difficulty report · Fmc · Boeing 737990ER

Difficulty date
October 15, 2023
Submitted
October 19, 2023
Operation
Air carrier
Aircraft
N491AS
Make and model
Boeing 737990ER
Aircraft serial
44109
Aircraft time
29,547 hours, 9,220 cycles
Part
Fmc
Part number
8221604102
Part serial
4737GK
Condition
Faulty
Location
E/E Shelf E1-1
Part time
29,573 hours, 9,227 cycles
Stage of operation
LD
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

AT ABOUT 200 AGL DURING AUTOLAND, WHEN STABILIZER TRIMMED NOSE UP, AN APPROACH WARNING ANNUNCIATED ON THE HUD, THE AUTOPILOT DISENGAGED & THE AIRCRAFT BEGAN LEVELING OFF AT ABOUT 100 AGL RUNWAY 16R. GROUNDED - YES. (RESOLVED ON W/O: 1972063 TASKCARD: N/R-00001 ) CONFIRMED FAULT, DFCS FAULT HISTORY SHOWS FAULT MSG# 22-11479 "P SPM MON", FLT LEG 14, A/P DISCONNECT, G/S ENG, CHAN-A FAULT, (SENSOR VALUE AT TRIP) FCC-A P-ACT=-5.2 DEG, FCC-B P-ACT=9.0 DEG, ALT=514 FT, A/S=144 KT. ACCOMPLISHED FIM 22-14 TASK 801 "FCC INTERNAL PROBLEM" FAULT ISOLATION, TROUBLESHOT TO DEFECTIVE FCC-A. REMOVED & REPLACED FCC-A REF AMM 22-11-33. VERIFIED CORRECT FCC OPS SOFTWARE PER AIPC. ACCOMPLISHED DFCS LAND VERIFY TEST (GP 49) REF AMM 22-11-00, DFCS LRU REPLACEMENT TEST (GP 35) REF AMM 22-11-33, HGS SYSTEM TEST REF SMM 34-36-00, OPS CK NML. AIRCRAFT RELEASED FROM MEL 22-20B & MEL 22-99B, C/N 15057491. SEAMC NOTIFIED "ASHRAF." REVERSAL OF CONFIGURATION CHANGES NOT REQUIRED. REF L/P 60736609 FOR A/C APPROACH SURVEY.