Sudden loss of all flight instruments

[Art]

Lately I've been flying the TBM quite a bit and appreciating how detailed the simulation is. So far any of the problems flying it were due to oversights or lack of preparation on my part. However yesterday something happened for which I have no explanation:

I was taking a new airframe on a ferry flight across the North Atlantic. On the second leg from EGPF (Glasgow) to BGGH (Nuuk), after four and a half hours of an uneventful flight there was a single warning ping sound and all flight instruments went dark. I was over central Greenland at 30000 ft. I immediately turned on oxygen and got to a much lower flight level. It turned out the engine was still running (just from the sound and performance). With a lot of effort I was able to still fly the plane to Nuuk with the help of the AVITAB, having only the ESI and the Standby Compass as flight instruments. The autopilot was not available either, I was not able to get a clear sense of whether the electrical trims were working.

I checked the fuses, they were all in and I flipped a lot of switches to see if the instruments would come back on - nothing! When finally approaching Nuuk I was surprised to hear AFIS come on - since the intercom panels were also dark I had no way to check or set other frequencies.

On approach I did not do a fly-by (visual landing gear check) since I had no tower frequency, I was not sure if the gear was down and tried using the landing gear extension hand pump as well. (I did the emergency gear lowering procedure incorrectly, I now know, but before that the gear had not come down either.) I chose to land immediately, gear or no gear, since I assumed fuel might be low from not having been able to fly in a straight line and at lower altitude with unknown power settings. (I was right, on the ground it turned out there was hardly any fuel left.)

It turned out the gear was not down and I did a belly landing with damage beyond repair to the airframe. I have no idea why this incident happened. I checked the battery after the crash, and it was in a normal loaded state. In the TBM900_Log.txt I see "Component Pilot's Primary Flight Display has failed suddenly due to an internal electrical fault" and a lot more similar lines.

Unless I find the error the plane will not feel save for long trips any more. So I would appreciate any input.

Thank you!

 

Attached is the TBM900_Log.txt (The trouble seems to start at 2021-07-03 00:49:14)

TBM900_Log.txt

Edited July 5, 2021 by Art

[Goran_M]

Quite a long log file.  While I check through it, can I ask, did you check the maintenance manager for any failures?

[Art]

Thank you for responding so quickly!

Yes, I was trying to check the maintenance manager. But I got something like "aircraft damaged beyond repair" under any of the sub-categories and it was not possible to see any details.

Looking at the file I now see that I have gone through several airframes in this session. I was doing test flights trying to simulate a burn-out and restart the engine in flight (unsuccessfully), some resulting in emergency landings off airport and crashes.

Also, for more realism and because I felt I had mastered flying the plane, I had turned all in-flight tips off on this trip...

Edited July 4, 2021 by Art

[Goran_M]

When the maintenance manager tells you the aircraft is damaged beyond repair, it's time for a new airframe.

It's fine if you want to practise failures, but some failures will end up destroying the airframe.

[Art]

Thanks. What happened though is I did those test flights, sometimes crashing the plane, but then I always created a new airframe. I just did not reload the TBM when doing so, should that be done? (I mean I created the airframe and started flying it, not selecting it anew via the X-plane Flight Configuration.)

I had X-plane and the TBM loaded for more than a day, putting the computer into sleep mode in between (Win10). At one point I created a new airframe and with that I set out on this trip. At the end of this flight in which the instruments failed I had a crash landing due to the gear not coming down. Then the maintenance manager told me the aircraft was damaged beyond repair.

I have extracted the part of the original TBM900_Log.txt that pertains only to this trip.

As I'm not familiar with reading these log files I can't tell exactly what the boot sequence for a new airframe looks like. So I've included the last few lines pertaining to the previous, damaged airframe. The actual boot sequence for the new airframe seems to start around line 6 or 7. The excerpt starts with what is line 30354 in the original log file.

My questions as to why the flight instruments and also the landing gear failed:

• Was it because something carried over from a previous, damaged airframe? Would it be saver to reload the TBM or even X-Plane when creating a new airframe?
• Was it pilot error? Is there any mistake I could make that could cause all instruments to suddenly fail (as well as the landing gear)?
• Is this an intended simulation of a malfunction that could happen on the real airplane? (I had not set any failures under X-Plane Flight Configuration.)
• Or is it not possible to know why these failures might have occurred?

TBM900_Log_excerpt.txt

Edited July 6, 2021 by Art

[Art]

On 7/4/2021 at 2:44 AM, Goran_M said:

When the maintenance manager tells you the aircraft is damaged beyond repair, it's time for a new airframe.

I understand. But in this case this is not what happened, please see my post above. It was a newly created airframe.

Edited July 6, 2021 by Art

[Goran_M]

On 7/5/2021 at 8:19 AM, Art said:

but then I always created a new airframe. I just did not reload the TBM when doing so, should that be done?

This is correct.

On 7/5/2021 at 8:19 AM, Art said:

At one point I created a new airframe and with that I set out on this trip. At the end of this flight in which the instruments failed I had a crash landing due to the gear not coming down.

This was very likely due to some kind of major failure.  Probably in the electrics.  Landing without gear extended will result in a damaged beyond repair TBM.  What you SHOULD HAVE done was manually pump the gear down using the emergency gear extension lever located under the floor, just aft of the centre console.

25 pumps gets the gear fully extended.  This would have given you a safe landing and then you would have been able to repair any electrics in the maintenance manager.

On 7/5/2021 at 8:19 AM, Art said:

Was it because something carried over from a previous, damaged airframe? Would it be saver to reload the TBM or even X-Plane when creating a new airframe?

100% no.  Creating a new airframe deletes the previous entries for the previous airframe.  When you create a new airframe, the last one is lost forever.

On 7/5/2021 at 8:19 AM, Art said:

Was it pilot error? Is there any mistake I could make that could cause all instruments to suddenly fail (as well as the landing gear)?

Possibly.  But it could have been something in the default X-Plane failures module.  We've seen some people report issues with the TBM failures and not being able to repair them due to some failure they have set in the default failures of X-Plane.  But seeing as you have confirmed this is not the case, it's likely something else.

On 7/5/2021 at 8:19 AM, Art said:

Is this an intended simulation of a malfunction that could happen on the real airplane? (I had not set any failures under X-Plane Flight Configuration.)

Absolutely. We've consulted with a TBM pilot and owner (the co-founder of Foreflight) on all the little details and operating procedures of the TBM 900.  A small malfunction could easily and quickly snowball into something major.

On 7/5/2021 at 8:19 AM, Art said:

Or is it not possible to know why these failures might have occurred?

As in real world ops, failures happen, and it could be any number of sequences that lead up to them.  The key is to follow the appropriate checklists for the failure you are experiencing (in your case, loss of power and landing gear operation.) and do what you can to either re-establish power or land at the nearest airfield.  

 

Our TBM is extremely complex, and follows real world ops very closely.  If you experience a failure of any kind, you need to follow the appropriate checklists, otherwise things will spiral out of control very quickly.  

[Art]

Quote

What you SHOULD HAVE done was manually pump the gear down using the emergency gear extension lever located under the floor, just aft of the centre console.

25 pumps gets the gear fully extended.  This would have given you a safe landing and then you would have been able to repair any electrics in the maintenance manager.

Yes. I only thought about the gear too close to the airport and because I (rightly) guessed that fuel was very low I did not consult the POH In this hurry. So I pumped, but not enough (the gear control lights were not working either).

Quote

Our TBM is extremely complex, and follows real world ops very closely.  If you experience a failure of any kind, you need to follow the appropriate checklists, otherwise things will spiral out of control very quickly.

...and that is what makes it fun and challenging to fly! I appreciate that!
Yes, I should fly it a little less by intuition and pay attention to checklists and the POH a bit more.

Thank you for your detailed reply, I will take off in your TBM soon again, it is currently my favorite plane!

Edited July 6, 2021 by Art