PX4 F450 · 2023-04-08

Flight telemetry summary

Distance Meters

69.6 m

Maximum Altitude AGL

17.4 m

Maximum Ground Speed

4.99 m/s

Minimum Battery Percent

0%

Minimum Battery Voltage

10.09 V

Minimum GPS Satellites

8

Maximum GPS HDOP

1.7

Flight Modes

AUTO_LAND, AUTO_LOITER, STAB, ALTCTL

Maximum Distance From Home Meters

37.8 m

Maximum Distance From Home Time

51s

Average Ground Speed

2.19 m/s

Maximum Climb Rate MPS

3.46 m/s

Maximum Descent Rate MPS

-15.98 m/s

Battery Consumed MAH

95.3 mAh

Battery Consumed Wh

1.4 Wh

Voltage Sag

5.37 V

Flight Mode Seconds

AUTO_LAND: 9s, AUTO_LOITER: 1s, STAB: 21s, ALTCTL: 22s

Maximum GForce

18.89 g

EKF Healthy

No

Weather at the flight

Source

open-meteo-archive

Sampled At Utc

2023-04-07T08:00Z

Latitude

35.46

Longitude

119.54

Temperature C

13.4 °C

Wind Speed MPS

2.91 m/s

Wind Direction Degrees

344

Wind Direction Cardinal

NNW

Weather Code

0

Weather Description

Clear

AI flight report

This was a very short flight — 52 seconds total, covering just 70 m of ground track, with the aircraft ending up 38 m from home at the final sample (0:51). Conditions were mild and calm (13.4°C, clear skies, wind only 2.91 m/s from the NNW), so weather is unlikely to have been a driver of what follows. The altitude profile is unusual for a fixed-wing: it climbed to a peak of 17 m above home by 0:10, then dropped sharply, with the log recording negative altitude-above-ground readings at 0:15 (-8.8 m) — a sign that the altitude estimate itself was unreliable rather than that the vehicle went underground.

The flight was troubled almost from the first second. At 0:00, before it had even left AUTO_LAND, the log flagged a 37 m disagreement between the barometric and fused altitude estimates — a large mismatch that suggests the state estimator was already unhealthy at the start. By 0:06 a sustained motor imbalance appeared (motor 2 at 1365 µs vs motor 3 at 1153 µs), which widened to an 874 µs spread at 0:07 — a big enough gap that the mixer was clearly fighting a persistent asymmetry rather than just correcting a normal manoeuvre. That same second logged a 4.9 G impact. Things escalated quickly: battery-critical and EKF-unhealthy faults both hit at 0:08, a 72° attitude excursion at 0:09, and at 0:10 the autopilot declared a "no global position" failsafe and switched to STAB while altitude peaked. At 0:11–0:13 the vehicle was descending at up to 16.0 m/s (the flight's fastest recorded descent), the baro-vs-fused gap widened further to 43.3 m, and a second, much harder impact of 15.9 G was logged at 0:12, alongside motor 1 saturating near 1917 µs. The attitude reached 180° from level at 0:23. Altogether this sequence — early altitude disagreement, growing motor asymmetry, EKF failure, a steep descent, and two impact events — reads as a loss-of-control event rather than a normal landing, though the exact cause (e.g., a bad prop, a wiring fault, or a sensor failure) can't be pinned down from this data alone.

Battery behaviour is also worth flagging on its own: voltage sagged by 5.37 V over the flight, bottoming at 10.09 V at 0:13 (1.36 V/cell across ~4 cells), which is a deep sag for such a short, low-power flight and points to either a weak/aging pack or a load spike coinciding with the impact events. Two concrete things to check before the next flight: first, inspect motor 2 and its propeller/mount — the 212 µs asymmetry at 0:06 growing to an 874 µs spread at

Detected flight events

1. 0s — Barometric and fused altitude disagree by 37 m

   Barometric and fused altitude disagree by 37 m

2. 6s — Sustained motor asymmetry: motor 2 1365 µs vs motor 3 1153 µs (212 µs spread)

   Sustained motor asymmetry: motor 2 1365 µs vs motor 3 1153 µs (212 µs spread)

3. 7s — Impact or hard landing: 4.9 G

   Impact or hard landing: 4.9 G

4. 8s — Battery below 15%

   Battery below 15%. Battery at 14%. The aircraft should land as soon as possible.

5. 8s — EKF filter fault or high innovation variance

   EKF filter fault or high innovation variance

6. 9s — Flight mode changed to AUTO_LOITER

   Flight mode changed to AUTO_LOITER. The pilot or autopilot switched control behavior here.

7. 9s — Takeoff (altitude threshold)

   Liftoff at 11 m. The aircraft leaves the ground and starts its climb.

8. 9s — Steep attitude: 72° from level

   Steep attitude: 72° from level

9. 10s — [commander] Failsafe enabled: no global position

   Failsafe triggered: [commander] Failsafe enabled: no global position .

10. 10s — [commander] Failsafe mode activated

    Failsafe triggered: [commander] Failsafe mode activated .

11. 10s — Flight mode changed to STAB

    Flight mode changed to STAB. The pilot or autopilot switched control behavior here.

12. 10s — Maximum altitude: 17 m above home

    Maximum altitude: 17 m above home — the highest point of this flight.

13. 11s — Sustained descent at 16.0 m/s — risk of settling with power

    Sustained descent at 16.0 m/s — risk of settling with power

14. 12s — Impact or hard landing: 15.9 G

    Impact or hard landing: 15.9 G

15. 12s — Maximum ground speed: 5.0 m/s

    Maximum ground speed: 5.0 m/s — the fastest the aircraft moved over the ground.

16. 13s — Motor 1 at 1917 µs — near maximum output, little authority left

    Motor 1 at 1917 µs — near maximum output, little authority left

17. 30s — [commander] Failsafe mode deactivated

    Failsafe triggered: [commander] Failsafe mode deactivated .

18. 30s — Flight mode changed to ALTCTL

    Flight mode changed to ALTCTL. The pilot or autopilot switched control behavior here.

19. 51s — Motor 4 at 1949 µs — near maximum output, little authority left

    Motor 4 at 1949 µs — near maximum output, little authority left