Proud Mavic owner since a couple of days, had the opportunity to watch and read a lot about it during waiting time.

Some open questions remain, for example concerning Return to Home.

• Will obstacle avoidance be active when RTH is activated?
• Scenario: I have set RTH altitude set at 60m. Now I start at an base altitude of 10m (bottom of hill) and fly uphills, always keeping a relative distance to the ground of 50m. At 700m altitude, I loose signal, and RTH activates. Will RTH consider the changed elevation? (If not, it would now want to go to the elevation of my home-point + 60m, but since we're currently at 700, it would just...? Land?) Has anyone tried this? This is Actually my biggest fear. I lose connection, it lands in the middle of nowhere, and I can never find it again.
• Do i always have to calibrate Compass and xx before flying?
  

Sorry in advance if some of those questions are already answerd here, couldnt find them.

1) Yes Obsticle Avoidance should be active when returning to home, providing you have set it to in the settings.

2) The RTH height is set relative to the home point. So if that happens to be half way up a hill, and 100m above sea level that is the Base 0m as far as the mavic is concerned... if you fly below that level, it will always raise itself to +60m above takeoff point. (160m high in my example)

3) No do not calibrate the compass every flight, you're asking for issues that way. Ensure you get a good compass calibration before your first flight and you wont have issues. Only recalibrate the compass when the app asks for it or you have moved a considerable distance from the initial calibration. (100miles+)

I have also a question. If mavic is tracking something and lose the objekt, what happens?
Can i tell it to RTH in this case?

No you do not need to calibrate the compass every time. Do it once in a 'good' location and then only if you are prompted too by the app. I flew mine out oif the box in the UK after charging up the battery, to see if it need a calibration, it flew absoloutly fine.

I did then calibrate the compass in a field later as I am 8000 miles from China!

I don't calibrate the compass on my Phantom either, unless prompted. Never had a problem. If you take off & it hovers without drift, your compass calibration is good, if it starts to draw circles in the air, then the compass may be off. Key thing is get it in the air and then hover for 20 seconds or so any flight issues will show up and you can then deal with them. If you just go flat out vertical and somthing goes adrift it is harder to deal with.

gnom Posted at 2016-12-23 11:38
I have also a question. If mavic is tracking something and lose the objekt, what happens?
Can i tell it to RTH in this case?

The app just stops and a message appears to say that its lost the target. If the mavic reconises the target coming back into frame, it will auto resume. The Activetrack mode stays on and will display the "Stop" button on the screen untill canceled... Also the pause button just pauses the mode but will still remain "active" until canceled too

gnom Posted at 2016-12-23 12:38
I have also a question. If mavic is tracking something and lose the objekt, what happens?
Can i tell it to RTH in this case?

With Active Track it will hover if it loses the object its tracking.

If you approach the aircraft in active track and go under it it will lose you unless you have enabled backward flight, don't forget it cant detect obstacles behind itself!

gnom Posted at 2016-12-23 12:38
I have also a question. If mavic is tracking something and lose the objekt, what happens?
Can i tell it to RTH in this case?

With Active Track it will hover if it loses the object its tracking.

If you approach the aircraft in active track and go under it it will lose you unless you have enabled backward flight, don't forget it cant detect obstacles behind itself!

Thank you Danny-B-. And when i dont press any button but the battery gets empty?
Will it RTH without any interaction of the pilot?
Or can i tell her to do this?

OA is enabled by default be aware though it will just hover if it comes up against something unless smart RTH is enabled. It will then ascend to clear the object then continue.

Remember it will not go above the Max Altitude that you have set, again it will just hover until the battery goes flat then it will just land from that point.

Please also bear in mind its electronics can be confused by being blinded by the sun, it will interpolate the sun as an object close by and this has caused one or two RTH fails. It can only go on the data it receives to its sensors and it cannot think its way out of a problem.

Switching to sport mode will disable the OA functions by default.

Thank you very much, that helps a lot.

gnom Posted at 2016-12-23 12:45
Thank you Danny-B-. And when i dont press any button but the battery gets empty?
Will it RTH without any interaction of the pilot?
Or can i tell her to do this?

Low battery will initiate a RTH, along with all the limitations that that entails - Direct flight to the home point, it may encounter something in the way, only with smart RTH enabled will it ascend to clear, to the Max Altitude (not RTH altitude) otherwise it will hover.

If the Critical battery level is reached it will land wherever it is.

So if its coming back into a stiff breeze and hits critical battery it will stop and land.

Remember RTH is a flight aid and it will get your aircraft on a path home, directly from where it is, so if you flew behind or under something there is a risk of hitting it!

It won't rescue you from poor airmanship, so take care with it!

Danny-B- Posted at 2016-12-23 12:27
1) Yes Obsticle Avoidance should be active when returning to home, providing you have set it to in the settings.

2) The RTH height is set relative to the home point. So if that happens to be half way up a hill, and 100m above sea level that is the Base 0m as far as the mavic is concerned... if you fly below that level, it will always raise itself to +60m above takeoff point. (160m high in my example)

I understood your answers for 1. and 3, thanks.

Concerning 2, I didnt really. Let me rephrase my question:  What happens if i press RTH button when the drone is above RTH altitude, but it can't descent to RTH altitude due to terrain? Will it just land?

TobH Posted at 2016-12-23 13:11
I understood your answers for 1. and 3, thanks.

Concerning 2, I didnt really. Let me rephrase my question:  What happens if i press RTH button when the drone is above RTH altitude, but it can't descent to RTH altitude due to terrain? Will it just land?

Ahh i see, In that case i guess you would be reliant on obstacle avoidance. if set in the options it will always try to make its way home, I for one wouldn't put my whole trust in that and would rather set my RTH height to that above ANY obstacle within range ... if that happens to be 120m (max legal limit) then so be it.

In theory It should always avoid the obstacle.... flying round, or up and over. but avoid this if you can.

In your scenario are you talking about flying from a valley and then behind a hilltop?

TobH Posted at 2016-12-23 21:11
I understood your answers for 1. and 3, thanks.

Concerning 2, I didnt really. Let me rephrase my question:  What happens if i press RTH button when the drone is above RTH altitude, but it can't descent to RTH altitude due to terrain? Will it just land?

From the manual:

If Return to Home (RTH), including Smart RTH and Low Battery RTH, is triggered and the aircraft is further than 20 meters from the home point:
1. It will return to home at the current altitude if flying at or above the RTH altitude.
2. It will ascend to the RTH altitude if flying below it.

So answer to your question is it will RTH at your current altitude if you are already above what you have set.

FlashGJ Posted at 2016-12-23 17:20
From the manual:

If Return to Home (RTH), including Smart RTH and Low Battery RTH, is triggered and the aircraft is further than 20 meters from the home point:

Yes, thanks, thats the info I needed! Thats at least a bit better than what I feared. Have to put it to the test... In any case, in a perfect world RTH would smoothly adapt to terrain and always "add" RTH altitude relative to terrain.  

Danny-B-: Yes, starting from valley, (900m) then flying uphills and back. (1300m)

I've been almost spam-like posting this all over.  Just want to make sure other users are aware, the RTH function in the manual for mavic (pg 16) appears to be accurate.  However, the beginner tutorial, flight sims, and even in APP while flying is NOT accurate.  The discrepancy is when the Mavic is 5-20m from home location.