SDR ASAA2019022728399

Service difficulty report · Unknown · Boeing 737890

Difficulty date: February 27, 2019
Submitted: March 1, 2019
Operation: Air carrier
Aircraft: N587AS
Make and model: Boeing 737890
Aircraft serial: 35684
Aircraft time: 43,668 hours, 12,704 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Unknown
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

WHILE IN CRUISE, 300 NM NORTH OF HNL, LEFT F/D MASTER, LNAV/VNAV DROPPED OFF & AUTOPILOT WENT TO CWS R. NO OTHER INDICATIONS, SWITCHED TO AUTOPILOT B, LNAV/VNAV ENGAGED, THEN GOT VTK ON LEFT NAV DISPLAY. SOON 10-15 SEC LATER LNAV/VNAV AGAIN DROPPED OFF & AUTOPILOT WENT TO CWS R. LEFT VTK WENT AWAY AND RIGHT NAV VTK CAME ON. PUT AUTOPILOT A ON IT ENGAGED. GROUNDED - YES. CYCLED AIRCRAFT POWER, PERFORMED FMC BITE CHECK REF FIM TASK 34-61-TASK 801 ON FMC #1 & #2. BOTH FMC BITE CHECK PASS.