I want to share my last experience with a 2.6 APM. I have used APM board since 2011 in some Hex, qua and airplane.
Last week end I was using my hexa to take photograph for a farm. The hexa flew perfect in auto taking the photograph of 35 has.
Time of flight 17 min.
Altitude 140 mts
All the data is in the Tlog attached.
Battery used 50%.
At the end of the flight I have schedule a RTL and the hexa came back to the home and start the landing process.
When It was at 54 mts I switch from auto to alt hold to landing it, (throttle stick was around 65 % at the stiching moment, when I started the auto flight it was a 80%, so I have reduce from 80 to 65 as I always do when I flight in auto) . The hexa shut down the motors and fall down almost 30 mts or more I push my stick to full gas, I have seen that the motors started again but power was not enough to avoid the crash.
What sound strange was that the telemetry RFD 900 shut down also, there is no data save neither in the apm nor the telemetry PC information, this could happen if the board reset or shut down, but motors started when they were almost the ground?
I have flown this equipment a lot of time and I have never had a problem like this.
As I mentioned I am not sure that the motors have shut down due to a board reset because I have seen that they have started again pretty close of the ground before the crash and I did not have enough time to arm it again.
Has anyone had a problem like this?
Could anyone help me telling some info or any data to analyze in order to find the root cause?
Why this happen at the same moment that I switch from auto to alt hold
ArduCopter V3.2.1 (36b405fb)
Tarot Pro 650
Arduino APM 2.6
RX-TX Dragon Link
Telemetry RFD 900
Battery 16 amp.
Any help or comment is welcoming.
I have attached al the tlog and data available.