We have had 3 verified cases (2 planes, 1 copter) of Here+ GPSs safety switches being disengaged in flight leading to sudden crashes. In the two events involving planes, the switch was wet which may have contributed to the failure.
To remove the possibility of this sort of failure, we are changing the safety switch behaviour so that once the vehicle is armed, pushing the safety switch has no effect. Some users may not like this change in behaviour so the old behaviour can be restored by setting the BRD_SAFETYOPTION parameter to “7”.
We will be running a short beta of Copter-3.5.6-rc1 over the next few days followed by an official release.
Note that these safety switch behaviour changes are already included in the latest Plane and Rover releases.
Thanks for your support and any assistance in beta testing is greatly appreciated!