SDR ASAA2020111333555

Service difficulty report · Fmc · Boeing 737990ER

Difficulty date: November 13, 2020
Submitted: November 17, 2020
Operation: Air carrier
Aircraft: N428AS
Make and model: Boeing 737990ER
Aircraft serial: 36353
Aircraft time: 17,985 hours, 5,700 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Fmc
Condition: Failed
Stage of operation: AP
How discovered: O
Nature of condition: J
Precautionary procedure: O

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

What was found

DURING APPROACH ON ARC INTERCEPT WAS EXECUTED ON FMC LEGS PAGE. FOLLOWING EXECUTION A DUAL VTK WAS DISPLAYED AND BOTH MCDUS REVERTED TO THE MENU PAGE WITH NO VISIBLE FMC PROMPTS. THE APPROACH WAS CONTINUED IN VISUAL CONDITIONS AND BOTH FMCS RETURNED TO OPERATION AND ACCEPTED PROGRAMMING TO THE PROGRAMMED APPROACH. THE WAYPOINT SELECTED PRIOR TO FMC FAILURE WAS CRSNR AND THE RNAV (RNP) M27. GROUNDED-YES. PERFORMED B737-900 FIM 34-61 TASK 836. NO FAULTS DISPLAYED, SYSTEM OPERATIONS NORMAL.