YAWing while copter is standing on table

Today I witnessed weird behavior of hexa 3.5.3. After flight copter was standing on the table and suddenly horizon began rotate on Mission Planner reporting Compass variance and bad AHRS. Horizon tilted too even-though copter was quite level. Logs are not available due copter was unarmed. This occurred on table but if happens in air result s might cause serious stability issues. HW is Pixhawk 1 without external compass. Copter flew quite ok and autopilot seems to be fine, at least most of the time. I didn’t touch the copter when this occurred.

What I did:

  • I flew casual 7 min flight
  • Took copter indoors and perhaps powered off, or not. I’m not sure
  • Connected copter via USB to PC and began download logs
  • Got several errors and log list didn’t appear
  • Rebooted copter and tried again and same error occurred
  • Cleared all logs from memory
  • Left download / clear logs - window open background and began to check which options were selected to be logged on parameters
  • After search from advanced parameters and then from basic? parameters list, copter went crazy
  • I tried to arm copter when it was rotating wildly on screen but arming wasn’t possible, which was correctly denied with these circumstances
  • Finally I rebooted copter and all was fine again

Copter has been on same spot on table countless of times. Table is wooden and closest metal structure (table sheet metal foot) is about 40 cm below autopilot under the table.

Short video is on Tube: https://youtu.be/-vd8CxLUxJI