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Hi,

I performed my maiden flight of a rebuilt APM Quad. After one good 8min flight I swapped the battery and took off again. After a couple of minutes in Loiter it suddenly flipped and crashed. Thankfully I was very low so damage was minimal. I am running AC 3.1.5.

I was planning to upgrade to AC 3.2 beta today however as this was a maiden with the new frame, I though if something were to have gone wrong there would be too many variables to troubleshoot. As luck would have it...something did go wrong!

It was quite gusty and with every gust of wind the quad would wobble on the pitch axis quite violently. I would say about 20 - 25 degrees roughly. I felt it was not handling the gusts well at all compared to earlier the 10 inch props on shorter arms. Even on the first flight where I did not crash I did notice this issue. 

The recent changes I made include adding the AIMDROX aluminum long arms, upgraded motors Sunny Sky X3108 720KV with APC 12x3.8 SF Props. So basically, longer arms, lower KV motors and bigger prop. Could this combination coupled with the gusty winds caused it to have flip? Quad weight is 2kg with battery.

Pic of the quad below:

The logs shows 2 errors that are evident but could they have caused a flip?

1.Many MAIN-1 Errors at the end

2.A number of GPS-0 & GPS-2 errors - I was aware of this as my external LED's indicated this. However why do I have so may GPS Err2&0 when my HDOP is between 1.2 and 1.7?

Request if someone who can analyze these logs well please help me trouble shoot why this happened. I do not know which areas of logs to review to try and trouble shoot this issue. Any help would me much appreciated.

Reading the WIKI I realized I need to look at the DRoll message in NTUN and the ROLL in ATT. Here is what I find. But I don't know how to find the root cause for this.

I am attaching the logs of both the good first flight and the second flight when it flipped and crashed.

Thanks

Arshish

10-43-22 - GOOD FLIGHT.log

11-07-56 - CRASH FLIGHT.log