What happens after Mission is complete and GCS connection lost

Hey there

We are building a Long Range Quadcopter. The estimated flight time is about 1 hour and it has a Cube Black as flight controller.

i have a Frsky RC for take off and landing. on the Copter there is a Raspberry Pi with LTE connected to the flight controller. Mavproxy will then forward mavlink over LTE to the ground station.

we did some test flights and it performs well. ofcourse the FrSky looses the conection soon but this does not matter since the mission is on the Pixhawk and it is in Auto mode.

The failsafe is set to Continue if in Auto mode. But recently i did a mistake but got lucky to be in range of the Frsky Radio.

i created a mission with just 1 waypoint far away. during the flight, the LTE connection broke up and did not recover. i then quickly triggerd RTL on the Radio wich still had weak connection and the quad returned safely home.

but what would have been happening if i did not trigger the RTL? would the quad enter failsafe (RTL) after mission complete? or would it stay at the last waypoint forever?

thank you for your reply


There are some failsafe parameters related with taking action when gcs connection is lost. Please look at FS_OPTIONS, FS_GCS_TIMEOUT, FS_GCS_ENABLE
You can also add rtl command at the end of your mission items list.

Thanks for the quick reply. i know that every mission should end with RTL or Land… but what if it gets forgotten by accident or multiple missions should be made without land inbetween?

The FS parameters are already known, but AFAIK the autopilot stays in Auto mode after the mission is complete right?

i always reload the mission from copter to missionplanner before I start a mission - to be sure I have the right mission and every waypoint was transmitted correctly. that is done within some seconds and helps a lot for me. maybe someone has a better idea?

No. If the GCS FS parameter is set to RTL after GCS loss then the aircraft will RTL and disarm itself. The mode on the ground will be RTL until it is switched by either the GCS or transmitter.

Yes but FS Option is set to “Continue if auto” so it will continue the mission and if the mission has no RTL or Land it will hover at the last waypoint until battery failsafe will trigger, is this right?