AXL30 - BABINA FLIGHT INVESTIGATOR REPLAY | V4 - stage-colored pathway, RTL in red, drag the divider to resize columns

T+00:00

Live Telemetry

Mode
-
Altitude AGL
0 m
Battery
23.6 V
Range from home
0 m
Total distance flown
0.00 km
 
RTL COUNT (failsafe returns)
0

Stage Colors

Event Log

Logs Considered For This Report

Onboard dataflash: "Babina last flight log (1).BIN" - 47.8 MB, ArduCopter V4.6.3 (92b0cd78), CubeOrangePlus.
Streams parsed: MODE (150) - flight-mode changes & reasons; ERR (171) - failsafe/subsystem errors; EV (41) - arming/landing events; MSG (314) - autopilot text log; BAT (16,587) - voltage/current/consumed/IR; BARO (33,174) - altitude; GPS & POS (16,587) - position/speed/satellites; ATT (16,587) - attitude demanded vs actual; CTUN (16,587) - throttle & climb; RCIN/RCOU (16,587 each) - RC input & motor outputs; VIBE (49,761) - vibration/clipping; POWR (16,587) - avionics rail; IMU (124,407); PARM - full parameter set.
GCS captures: BARO.Alt, BAT.Volt, BAT.Curr, GPS.Spd, HEAT.Temp value graphs; map ground-trace; NOAA lat/long distance verification (~4 km).

Conclusion - Investigator Summary Note

AXL30 was lost to propulsion battery exhaustion in flight, not to any motor, ESC, firmware, navigation or control failure. The 12,000 mAh-rated pack was electrically empty at ~9,500-10,000 mAh: voltage fell gradually from 23.6 V at take-off, hit the LOW failsafe at 20.29 V (8,990 mAh) and CRITICAL 40 seconds later, then collapsed to a 5.04 V floor in the final two minutes, saturating all four motors and dropping the aircraft from ~70 m at 15.6 m/s, 3.53 km from home. The replay above makes the accident chain visible: 52 range-correlated radio failsafes (orange dots - none below 1.3 km) forced repeated RTL turn-backs that stretched a 3.9 km leg into 9.77 km of flying and eroded crew trust in warnings, so both battery failsafes were overridden within seconds - removing the last two automatic recoveries. Every automated protection fired correctly; the control system held the aircraft level to the ground. Corrective priorities: qualify and retire weak packs, activate capacity-based (mAh) failsafes, fix the RC link range, and treat a CRITICAL-battery LAND as inviolable.