SDR ASAA201805144594

Service difficulty report · Fmc · Boeing 737990ER

Difficulty date: May 13, 2018
Submitted: May 14, 2018
Operation: Air carrier
Aircraft: N494AS
Make and model: Boeing 737990ER
Aircraft serial: 41729
Aircraft time: 9,039 hours, 2,992 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Fmc
Condition: Malfunctioned
Location: Left
Stage of operation: NR
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

LEFT FMC ALERTED VTK ON LT MAP, BOTH CDU SCREENS WENT MENU. LNAV/VNAV DISCONNECTED, NO FMC FAILURE. THE FMC CAME BACK, BUT THERE WERE SEVERAL MORE VTK MESSAGES AFTER THE INITIAL ALERT. CONTINUED ON ONE FMC. ACFT GROUNDED. FFR FOR FLT 1 SHOWS FMC - L, PGM FAULT I. NO HISTORY FOR 60 DAYS. PULLED & RESET THE NR 1 FMC CIRCUIT BREAKERS. OPS CHECKED THE NR 1 & 2 FMCS. CHECKED GOOD IAW AMM 34-61-00.