Drone suddenly drops after a few seconds in POS_HOLD and STABILIZED mode

1

Hello PX4 community,

I am facing an issue with my quadcopter where the drone suddenly drops after a few seconds of flight. I am trying to understand the root cause.

Problem Description

  • The drone arms and takes off normally.

  • It hovers for a few seconds (around 3–6 seconds).

  • After that, the drone suddenly loses altitude and drops quickly.

  • This happens in both:

    • POS_HOLD mode

    • STABILIZED mode

Observations

  • Motors spin normally during takeoff.

  • The drone appears stable initially.

  • After a few seconds, thrust suddenly reduces and the drone falls.

  • I checked logs and noticed something related to hover thrust estimation, but I am not sure if it is the main cause.

Flight Controller & Setup

  • Flight Controller: MICOAIR_H743_V2

  • Firmware: PX4

  • Frame: Quad

Flight Modes Tested

  • POS_HOLD

  • STABILIZED

Both modes show the same issue.

And also this is not only with one i built the 3 quad 7inch, 10inch, 13inch same issue in all
takeoff then hold for few seconds then motor stop and drone drop.
Please help me to fix this issue

Logs

I have attached the flight log here for analysis.

Thank you

Flight Review - Quadrotor3.pdf (2.6 MB)