777 Problem During Arrival

[Virgin_A340 0]

When I am in the approach phase and I enter the STAR and all alt and speed constraints I activate it and then the AP and LNAV seems to command a sharp turn to something like 180 degrees away from the STAR route path. I then have to disconnect and reconnect the AP and LNAV and tell it to go DIR TO the next waypoint otherwise it will continue to fly away from the STAR route.Can anyone help?Andy S

[FOD 23]

When I am in the approach phase and I enter the STAR and all alt and speed constraints I activate it and then the AP and LNAV seems to command a sharp turn to something like 180 degrees away from the STAR route path. I then have to disconnect and reconnect the AP and LNAV and tell it to go DIR TO the next waypoint otherwise it will continue to fly away from the STAR route.Can anyone help?Andy S

Andy,Sounds like either a NavData problem or the AP installation. Have you recently reinstalled by any chance?John R

[Jim Harnes 13]

When I am in the approach phase and I enter the STAR and all alt and speed constraints I activate it and then the AP and LNAV seems to command a sharp turn to something like 180 degrees away from the STAR route path. I then have to disconnect and reconnect the AP and LNAV and tell it to go DIR TO the next waypoint otherwise it will continue to fly away from the STAR route.Can anyone help?Andy S

Think you should be selecting the STAR long before the approach phase. Sounds like you might be past a way point in the STAR that the FMS is directing a turn to "return" to the "next" way point on the CDU legs page.Just a thought.Jim Harnes

[FOD 23]

Think you should be selecting the STAR long before the approach phase. Sounds like you might be past a way point in the STAR that the FMS is directing a turn to "return" to the "next" way point on the CDU legs page.Just a thought.Jim Harnes

Never thought of that, Jim. A far more sensible solution.RegardsJohn