VTOL -- freeman2100 vertical take-off and landing fixed wing +pixhawk

[GregCovey]

@skyveyor

Decided to do a qtune. During the qtune, the battery voltage steadily declined to 21v. I had batt failsafe enabled at 21v and the drone responded by starting toward home. Around 5ft above the ground the nose of airplane abruptly pitched down and the drone crashed.

Hi David,

Here are some interesting recent events that may have also contributed to your crash. It’s a warning on using the latest releases until they have been vetted over time.

@tridge

I’ve just released plane 4.0.4beta1. This release includes a significant number of changes from 4.0.3. Key changes are:

• re-sync the 4.0 release with Copter-4.0, bringing them in line so as to maximise cross-vehicle testing
• fixed a timing issue in IOMCU that could lead to loss of RC input frames and increased latency of output to ESCs on the IOMCU
• fixed a bug in restoring gains in QAUTOTUNE that could cause the aircraft to be unstable on leaving QAUTOTUNE mode

WARNING! AutoTune bug in Copter-4.0.1/4.0.0