Loss of Aircraft due to GPS Speed Drop/EKF Velocity Reset despite active Airspeed Sensor

ArduPlane Plane 4.6
1

Issue Summary: I recently experienced a total hull loss after my flight controller initiated an uncommanded, aggressive nose-down pitch. Despite having a functional and calibrated airspeed sensor, the autopilot appeared to react to a GPS speed drop (to 0 m/s) by pitching the aircraft down to over 60°, far exceeding my defined pitch limit of 15°. The aircraft descended from 400m to the ground in approximately 4 seconds.

Flight Details:

  • Altitude: 400m AGL.

  • Incident: GPS speed suddenly reported 0 m/s.

  • Autopilot Response: Aggressive pitch-down (>60°) to regain speed, seemingly ignoring airspeed data.

  • Configuration: EKF sources were set to non-GPS, yet the velocity drop still triggered the maneuver.

Questions:

  1. Is there a specific parameter to force the autopilot to prioritize Airspeed over GPS Ground Speed for stall prevention?

  2. How can I completely isolate the EKF from using GPS velocity for pitch/throttle logic while still maintaining GPS for navigation?

  3. Why would the autopilot exceed the LIM_PITCH_MIN (15°) during this event?

thanks

2

Log? Post must be 20 characters

2 Likes
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unfortunately the sd was malfunctioned , thats why there is no log … sorry wish you can help without it

4

If you don’t have a log, how do you know that the GPS triggered the pitch down.

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everyhing was fine untill the gps speed incated 0 and all the sudden the plane tries to pitch down with throttle to gain air speed that was already 90 km/h

6

This is not answering my question, how you know this?

1 Like
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i have a analog video transmiter with osd

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Is this video somewhere available or is it not stored.
Do you have some other telemetrie data?
Was there some other indication on the screen?

1 Like