I was flying my research quadrotor on Nov. 2, and appear to have experienced a mid-flight reset of the Cube Black. This is a configuration which has been quite reliable for months, made from a Tarot Iron Man frame and Tiger Motor propulsion, and flown pretty much daily. I was especially interested in its performance that day because the prevailing winds were roughly 10-15 m/s and I wanted to know if I could count on this airframe in a coastal situation which has similar winds.
My normal flight profile is to make repeated climbs and descents over the same location, between 5m and 130m. I’ve instrumented the quad to measure physcial quantities and encode them into MAVLink packets which the flight controller forwards to the ground; you can see them as data16 and data32 packets. Also, a PingRX ADS-B receiver is aboard, connected to GPS2 at 57600 baud.
In this flight, the quad did one complete up/down profile, and had just started down from the top of its second ascent. The observed behavior was that all motors throttled to zero and the craft fell to the ground. The impact was sufficient to unmate a battery connection, so it was impossible to determine the quality of that connection after the fact.
The dataflash log abruptly ends, showing no indication of any in-flight problem. The telemetry log, though, shows the data coming to a complete halt at 9:12:47, followed by a “Calibrating barometer” text message, and then most of the traffic was data stream requests and, crucially, more of my data packets and some ADS-B receiver health reports, at least until impact, after which the only packets recorded were being emitted by Mission Planner. This suggests that the entire aircraft had no discontinuities in its battery power delivery, at least until impact.
No more dataflash log files were generated from that flight. In doing a post-crash assessment, I connected the Cube Black to Mission Planner to check it for damage, but found it to be nominally OK; nevertheless, there was no mention of any watchdog reset history.
I noticed another topic discussed a vulnerability related to Serial5 which was patch in 4.0.5-rc2, and I’m left wondering if excessive ADS-B packets from the PingRX receiver, especially at the flight apex where its RF horizon was probably some 150 miles, might have been a factor:
Dataflash log: https://drive.google.com/file/d/1Bx3LvCrNupOug5zhvG72F1QmA6UyTzma/view?usp=sharing
Telemetry log: https://drive.google.com/file/d/1mLE_vMAkufBIq1arMUwNR4g1tKWcgp5A/view?usp=sharing