Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Air Traffic Control Issued New Clearance; Flight Crew Overcame Equipment Problem
Aircraft
During preflight while briefing the HOLZ9 RNAV departure we saw a discrepancy between the flight plan points and the MCU (Mode Control Unit) NAV display; which displayed a right 360 degree magenta turn just after takeoff. We reloaded the SID for both 25 left and right but the turn would reinsert itself after about a 15 second delay. Called maintenance and wrote an AML (Aircraft Maintenance Log) discrepancy; we also informed the dispatcher and the duty officer of the problem. Maintenance reset the circuit breakers but the turn remained on the NAV display. After more consulting between LAX maintenance they said they had seen this before and the turn would clear itself when we lined up on the runway. We assessed the operational risk and decided we would taxi out and see if the turn would remove itself from the display when we lined up for takeoff; if it did not clear itself we would cancel our clearance and taxi off the runway and then ask clearance for the LAXX 7. The anomaly did not clear; we cancelled our takeoff clearance and taxied clear. No traffic separation issues occurred. Once stopped on taxiway Alpha we executed our game plan refilling and receiving clearance for the LAXX7 SID. No anomaly appeared with that SID; flight continued with no further issues. Navigation error on MCU displayed that did not match the waypoints on MCDU.
Wide body First Officer reported requesting a different departure from LAX when their FMC showed a wrong turn programmed on the original HOLZ9 departure.