Flight plan drawn incorrectly on ND

[ntlgr]

Aircraft Version

Development

Build info

{
  "built": "2022-02-21T07:56:45+00:00",
  "ref": "master",
  "sha": "29ebf866b086c2be9331241cbd5fb8858d6f7f95",
  "actor": "sidnov",
  "event_name": "manual",
  "pretty_release_name": "master:29ebf866"
}

Describe the bug

The flight plan is drawn incorrectly on ND. Some strange turns and a non-existent flyback is drawn in otherwise correctly sequenced waypoints. In the provided screenshot, the flight plan appears on the FMC and at the same time the problem is seen the ND.

Expected behavior

The flight plan should appear as a green line connecting the upcoming waypoints using the shortest flyable path between them.

Steps to reproduce

Not specific to a single flightplan; has been observed several times especially when approaching the IAF for a given flight. Screenshot belongs to a simbrief-generated flight plan from MMUN to MMMX.

References (optional)

No response

Additional info (optional)

No response

Discord Username (optional)

No response

[Benjozork]

The waypoint after USBER is CZA. The LNAV is drawing a fixed radius turn to it in a way that means it is behind you. This is not a correctly sequenced flight plan.

[Benjozork]

How did you import this plan ?

[ntlgr]

Routing was: VOBE2A VOBED V56 CZA UT20 MEDOS UT17 USBER DCT AVALI DCT REXES Specifically waypoints: MMUN CUN D258G VOBED UDGUV CZA ALPOM MEDOS USBER AVALI REXES MMMX

[ntlgr]

I can attach the simbrief file?

[ntlgr]

You are right about CZA, it shouldn't be there the sequence was incorrect. But was imported from simbrief!

[Benjozork]

CZA should be earlier in the flight plan. This is likely a bug with simBrief importing.

Can you post your simBrief ID actually ? It will allow me to use your OFP in the aircraft. Make sure to not generate any OFPs for about a day so I can load it myself.

[ntlgr]

Could be. Simbrief alias: MikePapa I'm afraid I have already generated another one :((

[Benjozork]

alright. for future ref, this is your username, not your ID. ID will be automatically indicated in the flyPad AOC settings

[Benjozork]

if you have the issue with another plan, just reply here

[ntlgr]

Will do. Thanks for looking into it. Probably a non issue

[Emenuez]

It usually happens on some occasions. What I do is do is make a DIR in the FMC the next waypoints and that usually solves the problem. It's not ideal but it works.

[merlinblack]

I had a weird one when flying from Beirut (OLBA) to Izmir (LTBJ) - imported from Simbrief. The STAR at Izmir was messed up. I'll try again and report back.

[Benjozork]

Need screenshots.

[kilocharlie1]

I am having the same issue with my ND, except it doesn't draw the line at all in correspondence with the waypoints, rather straight out from the runway I took off from

[merlinblack]

Experimental is crashing on me at the moment when I 'Request ...' from the MCDU to download from simbrief, so I can't try it again right now. My Simbreif pilot id is 392990 and the flight plan is my OFP - anyone wants to try it.

[ntlgr]

@Benjozork I believe I have found what the issue is. I think the turn arcs on the ND are drawn based on the current aircraft speed, and not based on the planned speed for that leg, Some evidence: If you look at the two screenshots I have attached here, you will see the ILS Z approach to SEQM 36. The waypoints are configured manually (as the approach is not available in the data set). While I am still enroute, the flight path is drawn erratically. Later, I descend and decelerate to the speeds required to fly the approach, and the ND is drawing it perfectly. The plane also flew the path correctly. NO changes have been made to the waypoints in between the screenshots. Hope this helps

[Benjozork]

That is not the same issue, though.