SDR ASAA2019092330807

Service difficulty report · Fmc · Boeing 737990ER

Difficulty date: September 23, 2019
Submitted: September 25, 2019
Operation: Air carrier
Aircraft: N440AS
Make and model: Boeing 737990ER
Aircraft serial: 41705
Aircraft time: 23,432 hours, 7,621 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Fmc
Condition: Malfunctioned
Location: Cockpit
Stage of operation: CR
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 FAILED MULTIPLE TIMES IN FLIGHT. VTK, MAP, A/T LIMIT MESSAGES INDICATED. FOLLOWED QRH PROCEDURE AND RESTORED BOTH FMCS. LEFT FMC FAILED MULTIPLE TIMES AGAIN WITHIN 15-20 MINUTES. FOLLOWED QRH PROCEDURE TO "FMC BOTH ON R" PROCEDURE AND CONTINUED FLIGHT. GROUNDED - YES. PERFORMED FIM 34-61 TASK 801 - W/300 FAULT CODE ENTERED, LAST FLT SHOWED "PGM FAULT". PERFORMED FIMS' 34-61 TASK 807 AND 836. INTERMITTENT FAULT. INITIAL EVALUATIONS GOOD.