Another crash caused by a switch to a different flight mode....

After several good flights with my pixhawk equipped quad, i had a crash soon after take off immediately after switching to alt hold flight mode. The quad immediately rolled over and fell from the sky...

I don't understand the cause, especially because i had several good flights with the same configuration, i didn't change anything since then...

If somebody can give me a hint based on the log file i attach to this thread i will be very grateful.

I also attached the video taken from the go pro on the gimbal.

Thank you in advance...

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Anybody that can give me suggestions?

I think maybe motor,prop or esc issue

Firmware version?

Esc type?

FW is the latest, 3.1.5, I can exclude prop issue, about motor and esc i must check, but it's not likely, the drone rolled over exactely when i switched to alt hold, till that moment it was flying nicely as always.

Motors are Sunnysky V3508 580kv and ESCs are Afro 30 amp.

Is that environment have an internet or stanchion pillar

Don't understand what you mean...

like this

For sure not at close distance, also on google maps i can't see any in the area, do u think those antennas could interfere with the pixhawk? If so why would it do that at the moment of the flight mode switch?

I find out that the copter didn't go to halt hold straight away from stabilized mode. It was in stabilized mode, then went to Sport and only then to HaltHold (at row 5026, then 5109, 83 rows). During the 83 rows period, you can see the pitch going down to -1 in IMU and in IM2. You can see this movement also from the film. And only then the behavior got crazy. During the mode change, the RC2 is at 1300 while the others are around 1500 (neutral). Is the RC2 link to pitch which could explain the pitch movement ?

Hi Kiwi, thank you for spending time analyzing my crash... Yes, RC2 is elevator (pitch).
The reason the flight mode passes through sport mode before alt hold is that i configured two 3 pos switches of my taranis for the mode change, and to give time to activate both switches to select a mode there's a time lag of 0,5 seconds before ch5 sends the approprate pwm level for the selected mode, the problem is that in that 0,5 seconds the pwm level of ch5 goes to midposition that is the level at wich sport mode is set. This has never caused any problem, but i could even reduce that lag to zero, but this will cause the taranis to voice confirm every flight mode is passed though with the 2 3 pos switches combination before reaching the last selected mode, that is anooying and confusing, with that lag of 0,5 secs the taranis will read only the last position selected.

Son, do you have bad experience around comm tower like the one pictured?

I am asking because I fly an Iris close to one of the towers, and sometimes I have funny glitches, but mostly poor 915 telemetry.

Thank you.


No, in the area of the crash there isn't any radio tower...

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