Failsafe for RC loss in QGC


In the RC loss failsafe trigger option is QGC. I have selected the option Return Mode. And, in my RC transmitter, I have put the throttle value -100%, which means if RC loses, the motors will be turned off. In such a scenario, which action will be executed? Will the drone return to the launch position, or will the motors be turned off, and the drone falls down immediately?

If you’re using an RC link like FrSky, CRSF, ELRS, etc, that has the option for “No Pulses” then the FC will sense the RC link loss regardless of the throttle position. What happens depends on your settings, but if you’ve set return home then drone should do just that. Be warned, if your testing on the ground with the quad armed, it will immediately disarm. This is normal, it won’t do it in flight if you have return home set and you are in a GPS guided mode.


Thanks for your reply. To clarify, in my RC transmitter failsafe settings, I put channel 3 (throttle) value -100%. This means if my quadcopter detects failsafe, it immediately puts the throttle value to -100%, basically disarming the copter. In QGC settings, I put “Return to Launch” for failsafe. So, during the flight, it will ignore the RC’s settings and execute the QGC’s one. Am I right?

I apologize for such questions as I am only a week old working in this domain.

You really need to look at what kind of control link you’re using. If you are using a basic RC style configuration like you would use on an RC airplane and the link loss only sends -100% on the throttle then yes, your drone will drop out of the sky.

Most modern control links let you set No-Pulses (or variations on the name). When the link is lost the receiver in the drone actually identifies the lost link and the FC then will perform whatever command you’ve set such as RTL.

Tell me what kind of RC link you’re using and I’ll try to give you more specific instructions if it’s a system I know. If I don’t know it, the odds are good that many others here will.


Thanks for the explanation. I am using Flysky FS-16X RC transmitter and FSia-6B receiver.

Well, that’s one system I don’t know first hand.

A quick google search of the manual leads me to this suggestion: It appears the failsafe mode for the FlySky radio store a given channel configuration on the receiver. If that’s the case then my suggestion would be to configure your radio and receiver so the sticks are neutral (including throttle), and that your mode switch is in the RTL position. This way if there’s a loss of signal your receiver will tell the drone to go into RTL mode and fly home. The problem with this method is the flight controller will never actually trigger or identify a radio fail safe. It’s not ideal but it’s better than nothing.

Hopefully somebody with FlySky experience will jump in with a better idea.

Here’s the link to the manual I looked at. Page 24 has the failsafe setting procedure.

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Great. I appreciate it. I will try the suggested methods and let you know. The drone is quite heavy, around 3.8 KG. That’s why I am a bit nervous to test these things.

You can test it on the ground. Take the props off, arm the drone, then turn off the radio. It can still be connected by a telemetry link or USB to your laptop to see Mission Planner. If the drone changes to RTL when you turn off the radio then you’re good.

If you get a normal failsafe system working and do the same test, the drone will disarm on the ground. That’s normal expected behavior.