Catastrophic crash on takeoff fixedwing

Did a hand launched takeoff and the plane began to fly erratically, with the motor completely cutting out for a moment. I attempted to take over in stabilized mode and then manual, I appeared to have little to no control in both. I am not positive what happened, would like some insight.

The land detector briefly went to the LAND state in the middle of takeoff.

The land detector parameters are LNDFW*.
I would start by reducing LNDFW_VELI_MAX and LNDFW_VEL_XY_MAX.
If you trust your airspeed calibration you can reduce LNDFW_AIRSPD_MAX as well.

Here’s a plot to compare with LNDFW_VELI_MAX (red), LNDFW_XY_MAX (dark blue), and LNDFW_AIRSPD_MAX (green).