After take off, and at the beginning of depature, the autopilot passed by the second waypoint and missed it. Then the autopilot flew straight forward to the north .The FMC showed that it was flying to that waypoint but it didn't follow the LNAV.

AIIR#6

The issue happened when it was heading for the next waypoint.

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When this happens to me, it seems to happen if the turn is too tight (mostly on the SID or STAR/APP), then has to turn in the opposite direction to reach the waypoint. It ends up passing the waypoint by too much distance, and fails to trigger that it has reached/passed it. It has happened on a straight section of the route, but those times were also part of the SID, not the main route.

Note. For now, I just copy the next waypoint on the LEGS page, and paste it to the current waypoint position (LSK1L), then it continues to follow the route.

Markoz wrote on Apr 7^th, 2021 at 4:24am:

When this happens to me, it seems to happen if the turn is too tight (mostly on the SID or STAR/APP), then has to turn in the opposite direction to reach the waypoint. It ends up passing the waypoint by too much distance, and fails to trigger that it has reached/passed it. It has happened on a straight section of the route, but those times were also part of the SID, not the main route. Note. For now, I just copy the next waypoint on the LEGS page, and paste it to the current waypoint position (LSK1L), then it continues to follow the route.

Yeah same for me! Happens to me every time I fly a SID. Workaround for me is to program a direct into the FMC.

I've had this happen off SID. I was in the middle of flight plan and about two waypoints before the STAR I ended up missing a waypoint. It went the same direction of the one prior to the one it missed. I ended up going 20 miles off course. It was easy enough to fix by just changing to the correct waypoint in the LEGS page but still annoying. It doesn't do it to me very often though.

Oh I should note that when it missed that waypoint it was a pretty big turn. I think 90 degrees. So that might have something to do with it. It only happened that one time as well. But it definitely happens quite often on the SID though it never happened in the US. Only happens to me in Europe.

Ryz wrote on Apr 9^th, 2021 at 3:43am:

I've had this happen off SID. I was in the middle of flight plan and about two waypoints before the STAR I ended up missing a waypoint. It went the same direction of the one prior to the one it missed. I ended up going 20 miles off course. It was easy enough to fix by just changing to the correct waypoint in the LEGS page but still annoying. It doesn't do it to me very often though.

But it seems that the current waypoint cannot be edit, I wonder how to replace the current waypoint with the next one and make it back to the correct course.

Did a little bit of testing about this one and it seems like there is a problem with flyby waypoints. Departed out of EDDW on WSN1M and EEL5Q, the fly over waypoints just work fine, but fo example when flying from DW090 to DW100 the 737 just starts to turn when its above DW100 and not before, but since DW100 is a flyby waypoint the aircraft should start the turn before the waypoint. And even after the turn the 737 overshoots the heading to DW101 to the left end just ends up trying to to a sharp right turn close to DW101 to overfly it(again a flyby waypoint...) after that the LNAV lost the flightpath completly...best workaround ist probably to do hdg select and select the next waypoint in the fmc.

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centurion88 wrote on Apr 9^th, 2021 at 5:07am:

Ryz wrote on Apr 9th, 2021 at 3:43am: I've had this happen off SID. I was in the middle of flight plan and about two waypoints before the STAR I ended up missing a waypoint. It went the same direction of the one prior to the one it missed. I ended up going 20 miles off course. It was easy enough to fix by just changing to the correct waypoint in the LEGS page but still annoying. It doesn't do it to me very often though. But it seems that the current waypoint cannot be edit, I wonder how to replace the current waypoint with the next one and make it back to the correct course.

You're not editing it with the scratch pad. Its done on the legs page. Lets say you missed waypoint 1 of the SID and are progressing to waypoint 2. Then you press LSK2L to select that waypoint then press LSK1L to make it active then press execute. That will make the second waypoint active and you'll progress to that one. Its the same procedure that you do when you want to proceed direct to a certain waypoint.

I had similar condition when manually fly a departure and off track buy a little (yeah, not much really...) and here is the savefile.

I think overall it's about when FMC recognized a waypoint was "crossed", some times you get radar vector and use HDG SEL or even manual to go off track, and the real aircraft will still cross a waypoint and go ahead even if you off line by 10+ miles.

It's not on manual, but as my observation, it should happen when crossing angular bisector of 2 legs

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Same issue.

Should be better in v.1009