Consider this scenario: I am flying my Mavic with visual line of sight but some distance away. I glance down at the controller and discover that I no longer have image transmission. Since, as I understand it, telemetry is carried on the image signal, I therefor also no longer have distance and altitude information from the drone (is that correct?). The control signal, which is separate from the image signal, may or may not still be connected; I do not know. It could even be dropping in and out intermittently; I have no way of knowing. Thus I do not know whether the drone has switched to RTH and is on the way home. I look up, but these old eyes can no longer pick out the drone against the background. Here is my quandary: if the drone is already in RTH mode and I press the RTH button, it will stop and just hover until the battery runs out. If however, the control signaL was still connected, then it is just sitting there hovering, waiting for me to press the RTH button, and the battery will eventually run out if I do not press it.  What does DJI recommend that I do in this situation? Press the RTH button on not? It seemns that there is a 50% chance that I will lose the drone which ever choice I make. Am I missing something here? I know that a low battery will eventually force it into RTH, but that is risky because a marginal battery may run out before the drone reaches home. I think that should be a last line of defense.

It would seem to me that the RTH button should NOT be a toggle, because there are situations in which the pilot may not know whether or not the drone is already in RTH mode. There needs to be some way to force the drone to RTH, no matter what it is doing. I guess turning off the controller would do that. Is that what DJI recommends?

Also, as I understand it, if I move the left stick up, that will take the Mavic out of RTH. This seems to me to be a recipe for disaster, especially for beginners who are still trying to sort through the overload of new information.

DJI Ken, I would really appreciate your input here. Thanks.

Loss of signal failsafe RTH, So loss of signal aircraft will ascend to failsafe height you have set and will proceed home if you then press RTH and you aircraft hovers then you have signal back, if you press RTH and don't have signal aircraft it won't hover but will continue home. Just make sure you have failsafe height high enough.

Thanks for your response Hallmark007. I apologize if I am wrong, but I don't think your response solves the problem. You correctly point out that loss of signal triggers Failsafe RTH. However that is true only for loss of the RC control signal.  Loss of video (and hence telemetry) does not trigger anything. So if I lose video & telemetry, I do not know whether I have also lost the RC control signal. If I did lose the RC control signal, then the aircraft is on the way home, and presumably at some closer distance will regain RC control signal. But without video/telemetry I do not know what has happened. There are three possibilities. Video & telemetry signal was lost and:

1. RC control signal was never lost
2. RC control signal was lost but not yet re-established.
3. RC control signal was lost and then re-established

In case 1 there is no problem. I press RTH and the aircraft returns home, even though without video/telemetry I do not know it until it arrives home.

Case 2 is also no problem. The aircraft is in RTH, and since there is no control signal, pressing the RTH button will have no effect, and the aircraft will continue home (although like Case 1, I do not know that it is on the way)

Case 3 is the problem. Since the RC control signal was lost (assuming longer than 3 seconds for this example), then the aircraft is on the way home. If it then reacquires the RC control signal (which I do not know because I do not have video/telemetry) and if I then press the RTH button the aircraft will stop and hover until the battery gets low enough to force it back into RTH. I consider this risky because a marginal battery could force a landing or even a crash before it reaches home. It makes no sense to stop an aircraft already safely on the way home.

So in Case 1 I should press the RTH button. In Case 2 it doesn't matter, and in Case 3 I should not interrupt an aircraft already returning home by pressing the RTH button. And the problem is that without video/telemetry I do not know which case it true.

And in all 3 cases, I must wait without touching any control on the RC Controller, hoping that the aircraft is returning. In case 3 I might have to wait as long as 20 minutes. In all three cases I am hoping and praying that I have not lost my Mavic, all because DJI has not given me a way to positively force the aircraft to return home in all three cases (except turning off the controller, which possibly messes up the flight record so that I would not have a record of the aircraft's last known position).

Again, I would like to know what DJI recommends that we do when the video/telemetry signal is lost. Press the RTH button or not?

Eventually, if your battery starts to die, your aircraft will RTH as well.