A320neo v2 systems froze mid-flight

[Sonkeli12]

Hi! Today I was flying the following route on Xbox when all of a sudden during the last steps of the climb, the autopilot switched off and the aircraft banked heavily to the left and down, activating TOGA LK. I cleared that and managed to level off the aircraft, then re-engaging autopilot. 

It did not, however, follow the set course or follow the set altitude. The aircraft also didn't accelerate and struggled to maintain speed at flight level 320. I had to end the flight since the FMC and thus, the airplane, was unusable. I remember having this same issue sometimes on the A310 as well, although on a different route. No directs or SEC FP were used.

LEBB 12 - AMTO4B 12 - TANGO - GODO2J 06R - LEPA ILS 06L-Z

The issue happened somewhere after WP TANGO. Weather was set to a clear preset.

[richboy2307]

Hi @Sonkeli12

13 hours ago, Sonkeli12 said:

the autopilot switched off and the aircraft banked heavily to the left and down, activating TOGA LK.

It sounds like the aircraft stalled and hence the stall protections activated as a result.

Next time this happens, could you please take some screenshots as we'd have to see the configuration of the plane, the active flight modes and particularly things like the position of the throttle levers & gear handles etc. before we can make any conclusions as to what happened. 

The previously reported things that can affect autopilot include:

• AI Assists (In the MSFS Assistance Options, ensure all disabled)
• Abrupt weather updates (Occasionally the sim's weather can update abruptly, specifically with regards to winds that can cause the airplane to overspeed or stall depending on the degree of difference between old vs new weather. This can also cause temporary severe turbulence, which in turn kicks off the AP.)
• Throttle Axis noise ( Noise in throttle axis inputs means that the the throttles fall out of the CLB detent occasionally, leading to the ATHR system not working properly even though engaged)
• Inadvertent deployment of gear/flaps/speedbrakes (which can cause excessive drag and lead to stalls or other AP/ATHR disconnects)

13 hours ago, Sonkeli12 said:

It did not, however, follow the set course or follow the set altitude. The aircraft also didn't accelerate and struggled to maintain speed at flight level 320. I had to end the flight since the FMC and thus, the airplane, was unusable.

Was the FMC and the FCU panel still responsive? Was the PFD still updating your current altitude/speed and responding to bank/pitch movements? If the systems were "Frozen" in place, then it was possibly a WASM crash which is a different issue altogether.

If all systems were still responsive to input, but simply not flying properly then its likely a case of throttle not in the right detent, and AP modes not having reverted/reset properly. In any case, it is difficult to say without any accompanying screenshots/video of the plane in that scenario which could provide more clues as to what was happening.

Thanks!

[Sonkeli12]

Hi!

Thanks for the reply. Unfortunately I cannot take a screenshot as I'm running on cloud gaming on Xbox One but will have to take a video or a photo next time. This issue has now happened to me again and it went away by restarting the simulator and then proceeding on the same exact route. 

As for the FMC, I could interact with the buttons but they wouldn't do anything. Trying to remove AP, A/THR or any other systems did not work either. The last time this happened, I made sure the throttle was in the right detent but it didn't make a difference to the modes, even when switched between TOGA, FLX and CLB. Could be a WASM crash, then.

I understand it is impossible to say exactly what happened without any screenshots, but thanks for the quick suggestions you gave!

[richboy2307]

3 hours ago, Sonkeli12 said:

As for the FMC, I could interact with the buttons but they wouldn't do anything. Trying to remove AP, A/THR or any other systems did not work either. The last time this happened, I made sure the throttle was in the right detent but it didn't make a difference to the modes, even when switched between TOGA, FLX and CLB. Could be a WASM crash, then.

 

3 hours ago, Sonkeli12 said:

it went away by restarting the simulator and then proceeding on the same exact route. 

Yep in this case it does appear to be a WASM crash based on this additional info.

In this case, please follow the guidance below to let us know exactly what interaction you made (button clicked, control input sent etc) just before you noticed the crash.

----------

What is WASM? 

Quote

WASM is an acronym for WebAssembly Module, and Microsoft Flight Simulator uses WebAssembly for scripting. Most commonly this means aircraft instruments, such as controls, panels, and displays, will function as intended (without WASM these instruments may not function at all or would function incorrectly). However, WASM usage is not only limited to aircraft. 

- Microsoft FAQ

Why do WASM Crashes happen?

These can be caused by either a) faults in the code, or b) in the way that code is executed by the sim.

a) Faults in Code

While we try our best to find and quash all bugs in code, we are still human. Mistakes or oversights can happen and sometimes these can lead the code to fail in certain specific instances, resulting in a WASM crash. These kind of crashes will be reliably reproducible, meaning you can have the crash nearly every time by executing the same code (e.g. by selecting something on the MCDU, or by pressing certain buttons on the plane, or by flying certain SID/STAR/APPROACH etc.)

These types of WASM crashes are actionable, and dependent on your reports of the steps taken immediately before the crash happened. These, if reproducible on our end by following the same steps, can be debugged and usually resolved in a following update.

b) Faults in the way the code is executed by the sim

Since SU15, we suspect, there have been instances of "random" WASM Crashes caused by a "memory allocation bug", wherein the sim tries to reserve memory (for WASM) that it does not have access to, as a result leading to a WASM crash. These types of WASM crashes are difficult to reproduce and not something we can address as its not an issue with the code, rather just in the way the sim tries to store and execute it in some instances.

These types of WASM crashes are not actionable on our part and would instead need fixes on the simulator's code (if possible).

So why did you experience a WASM Crash?

As mentioned above, we will first need to find out if the crash was (a) or (b). So you need to take note of what you pressed or things you did, just before you noticed this crash happen.

What systems stop responding, or what you cannot click after the crash is irrelevant as the whole WASM has already crashed, so anything using WASM will equally stop responding.

Additionally, please see if you are able to repeat the crash by following those same steps. Once you know, you can mention those steps to us, and we can try to reproduce on our end to see if its actionable.

Thanks!

[Sonkeli12]

Hi! If I remember correctly, I flew DRAG2Z SID from LEPA. It has a tight turn shortly after takeoff that the autopilot couldn't follow and turned the airplane to the wrong direction. I assume that's the reason for the crash. I don't recall pressing any buttons other than turning it into HDG mode after it stopped following the course.

The other crash was described in the initial post, where the aircraft banked heavily down left during last steps of the climb. There I remember regaining control and de-activating TOGA LK by turning A/THR off, after which the crash happened.

Hopefully this helps! Sorry for the lack of better detail on this instances.

[richboy2307]

1 hour ago, Sonkeli12 said:

Hopefully this helps! Sorry for the lack of better detail on this instances.

Thanks for sharing. Will see if I can reproduce a crash in those instances.