What happens during EKF Failsafe

I would like to know what exactly happens once EKF Failsafe is activated with respect to attitude estimation with the latest Copter firmware ( 3.6.8 or above). Does the copter switch to a DCM attitude estimator? Or does it switch to another EKF where external sources such as GPS, compass etc. are not used?

I’m trying to figure out if a failsafe occur due to GPS or Compass issue, can we be sure that Attitude estimation will still be good to use?

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When EKF failsafe, there is no backup on copter. It will only try to land or trigger parachute.

Ok. So during land mode, what attitude estimate does it use to keep the copter level? is it the same degraded EKF attitude estimate or something else?

I just wanted to bring the question back up.

From my experience of an EKF failsafe, the copter appeared to continue to use the EKF attitude estimate, which had gone way off. Actual roll was about 100 degrees left, artificial horizon was about 15 degrees right. The copter accellerated left and down at high motor power (presumably due to loss of altitude). I hit the emergency motor stop to minimise impact energy.