Hello,

I am experiencing a strange issue with the MCDU during my flight. The altitude constraints displayed on the F-PLN page appear to be completely corrupted.

I had left the aircraft flying on autopilot for approximately two hours while I was away from my computer. When I returned, I noticed that the altitude constraints on the F-PLN page were displaying completely abnormal values, consisting of long and seemingly random strings of numbers.

As shown in the attached screenshots, several altitude and flight plan data entries are displayed incorrectly instead of showing normal altitude constraints. Some waypoint information also appears to be incorrectly formatted.

This issue seems to affect more than just the visual display, as the MCDU is also calculating an incorrect Estimated Fuel On Board.

Here are the details at the time the screenshots were taken:

- Fuel on board: approximately 21,700 kg.

- Distance to waypoint HULTN: approximately 150 NM.

- Planned fuel at HULTN according to my flight plan: 16,400 kg.

The MCDU displays an estimated fuel at destination of only 4,000 kg, together with the warning " DEST EFOB BELOW MIN. "

Considering that I still had approximately 21.7 tonnes of fuel remaining at only 150 NM from HULTN, this seems significantly inconsistent with the MCDU's estimated fuel remaining at destination.

I suspect that the corrupted altitude constraints, or an inconsistency in the MCDU's flight plan data, may be affecting the fuel prediction calculations. The EFOB calculation could therefore be incorrect due to the abnormal altitude data displayed on the F-PLN page.

Has anyone experienced a similar issue? Is this a known MCDU bug, or could it be related to flight plan import or altitude constraint processing?

I have attached several screenshots showing the issue across different MCDU pages.

Thank you!

Edited 3 hours ago3 hr by Alexis.B

50 minutes ago, Alexis.B said:

Hello,

I am experiencing a strange issue with the MCDU during my flight. The altitude constraints displayed on the F-PLN page appear to be completely corrupted.

I had left the aircraft flying on autopilot for approximately two hours while I was away from my computer. When I returned, I noticed that the altitude constraints on the F-PLN page were displaying completely abnormal values, consisting of long and seemingly random strings of numbers.

As shown in the attached screenshots, several altitude and flight plan data entries are displayed incorrectly instead of showing normal altitude constraints. Some waypoint information also appears to be incorrectly formatted.

This issue seems to affect more than just the visual display, as the MCDU is also calculating an incorrect Estimated Fuel On Board.

Here are the details at the time the screenshots were taken:

- Fuel on board: approximately 21,700 kg.

- Distance to waypoint HULTN: approximately 150 NM.

- Planned fuel at HULTN according to my flight plan: 16,400 kg.

The MCDU displays an estimated fuel at destination of only 4,000 kg, together with the warning " DEST EFOB BELOW MIN. "

Considering that I still had approximately 21.7 tonnes of fuel remaining at only 150 NM from HULTN, this seems significantly inconsistent with the MCDU's estimated fuel remaining at destination.

I suspect that the corrupted altitude constraints, or an inconsistency in the MCDU's flight plan data, may be affecting the fuel prediction calculations. The EFOB calculation could therefore be incorrect due to the abnormal altitude data displayed on the F-PLN page.

Has anyone experienced a similar issue? Is this a known MCDU bug, or could it be related to flight plan import or altitude constraint processing?

I have attached several screenshots showing the issue across different MCDU pages.

Thank you!

Thanks for your report and attaching pictures to verify. Before I can log with the team to review, are you using default or Navigraph data?

Thanks!

Thanks for your reply!

I am using Navigraph data, no than the default MSFS data. The aircraft is linked to my Navigraph account, and I export my flight plans using Navigraph via the aircraft's EFB.

For reference, here is my flight plan :

Route: CPT5J CPT L9 BUCGO DCT FELCA DCT OFSOX DCT BANBA DCT LIMRI NATE NEEKO N618B HULTN DCT ENE DCT BAF HYPER1
( Flight Plan in PDF on attachment )

This is actually my third flight with the A340. I didn't encounter this issue during my first two flights, so it could be an isolated or intermittent incident...let me know if you need any further information.

EGLLKIAD_PDF_1793614202.44dbc557.pdf

Edited 2 hours ago2 hr by Alexis.B

24 minutes ago, Alexis.B said:

Thanks for your reply!

I am using Navigraph data, no than the default MSFS data. The aircraft is linked to my Navigraph account, and I export my flight plans using Navigraph via the aircraft's EFB.

For reference, here is my flight plan :

Route: CPT5J CPT L9 BUCGO DCT FELCA DCT OFSOX DCT BANBA DCT LIMRI NATE NEEKO N618B HULTN DCT ENE DCT BAF HYPER1
( Flight Plan in PDF on attachment )

This is actually my third flight with the A340. I didn't encounter this issue during my first two flights, so it could be an isolated or intermittent incident...let me know if you need any further information.

EGLLKIAD_PDF_1793614202.44dbc557.pdf

Thanks. Will test this when I'm back at my sim PC.

Appreciate your patience!

Update:

Interestingly, the MCDU display returned to normal after I performed a Direct To to one of the waypoints using the DIR page.

The corrupted altitude constraints disappeared, and the flight plan information was displayed correctly again.

I can't confirm whether performing the Direct To actually fixed the issue or if it was just a coincidence, but I thought this additional information might be useful for troubleshooting.