SDR ASAA2019092730850

Service difficulty report · Fmc · Boeing 737990ER

Difficulty date: September 27, 2019
Submitted: September 30, 2019
Operation: Air carrier
Aircraft: N453AS
Make and model: Boeing 737990ER
Aircraft serial: 36354
Aircraft time: 22,626 hours, 7,297 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Fmc
Condition: Malfunctioned
Location: Cockpit
Stage of operation: TO
How discovered: O
Nature of condition: O
Precautionary procedure: O

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

What was found

LNAV AND VNAV DISENGAGED ON TAKE-OFF ROLL. FLIGHT DIRECTORS DISAPPEARED FROM BOTH PRIMARY FLIGHT DISPLAYS. LNAV AND VNAV RE-ENGAGED WHEN RE-SELECTED ON CLIMBOUT WITH NO FURTHER PROBLEMS. THE EXACT PROBLEM HAPPENED ON TWO TAKE-OFFS IN A ROW. GROUNDED - YES. PERFORMED DFCS FLT FAULT REVIEW. FOUND FAULT MSG 22-11822 FMC DATA INV FROM LAST FLIGHT. PERFORMED B737-900 FIM 22-11 TASK 811, DFCS BITE AND FLIGHT DIRECTOR GROUP 12 OPS NRML - NO DEFECTS NOTED. ETOPS SIGNIF SYS, GROUND VERIFICATION SUCCESSFUL.