Pixhawk crash, I would appreciate some help to analyze log

Hi community,

Sadly my quad crashed after 21 minutes of flying, everything seemed normal before it suddenly fell from the sky. I have been flying the quad for a total of 8 hours with more or less the same setup without any issues before. I was flying with altitude hold around 40m and in more or less at one position when the quad dropped from the sky. From what I see in the log a brownout occurred at altitude 11.73m, but from what I can understand the issue happen before the brownout. I suspect mechanical failure after reviewing the log. Battery status was at 32%

Video of the crash, it makes a strange sound right before it goes down:

Log files (dataflash log):

Hardware information:

  • Pixhawk PX4 2.4.6 (Firmware Version V3.2.1)
  • UBLOX MIni NEO-M8N GPS GNSS + HMC5983 Compass Triple Band ANT (Primary GPS)
  • UBLOX Micro MAX-M8Q GPS GNSS + HMC5983 +SAW +LNA+ Triple Band ANT (Secondary GPS)
  • Power Module v5 - 90A
  • Tattu 16000mAh 22.2V 15~30C 6S 1P Lipo Battery Pack (separated battery pack/circuit for fpv gear)

See the included txt for full specification list.

Log auto analyses output:
Test: Autotune = UNKNOWN - No ATUN log data
Test: Balance/Twist = GOOD -
Test: Brownout = FAIL - Truncated Log? Ends while armed at altitude 11.73m
Test: Compass = GOOD - mag_field interference within limits (9.07%) Max mag field length (597.11) > recommended (550.00)
Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = FAIL - ERR found: GPS_GLITCH
Test: GPS = FAIL - GPS glitch errors found (1) Min satellites: 15, Max HDop: 1.53
Test: IMU Mismatch = GOOD - (Mismatch: 0.21, WARN: 0.75, FAIL: 1.50)
Test: Parameters = GOOD -
Test: PM = FAIL - 126 slow loop lines found, max 16.00% on line 730
Test: Pitch/Roll = FAIL - Roll (120.92, line 302416) > maximum lean angle (45.00)
Test: Thrust = GOOD -
Test: VCC = GOOD -


Adding some more details:

As mention before, battery status was at 32%, this was also confirmed afterwards when checking battery with my balance charger. Battery did detach from the power module when the quad hit the ground. I have newer seen Roll failure in any log before this crash (Roll (120.92, line 302416) > maximum lean angle (45.00)) I suspect mechanical failure after reviewing the log. Weather condition was a windy from time to time.

Known issues, vibration level has always been is a little high, I have reviewed some older logs looking at vibration level, more or less the same as in this flight. After adding a secondary GPS I started to receive GPS glitches, but the GPS-Sats (15 - 20) and GPS-Hdop (1.08 - 1.63) is always acceptable. Slow loop lines has always been a problem.

Logs are to big to include here, at least it fails on upload. See my Google disk share above.

I would truly appreciate any help that could shed some light on what caused the quad to drop from the sky. As explained, this quad has been reliable for many hours of flying before the crash, so I see no point in starting any rebuild since I do not know what caused the crash.