DJI Mavic, Air and Mini Drones
Friendly, Helpful & Knowledgeable Community
Join Us Now

RTH - mountain flight

vince-fr

Member
Joined
Jan 31, 2020
Messages
8
Reactions
7
Age
44
Location
Paris, France
Hi everyone !
My main playground for my M2 pro is the mountain environment, and since I'm planning to use it in quite high altitude, one thought came to my mind about the RTH function... Someone could give me more details? Here's my question :

Considering a crest that peaks at 3000m altitude, I take off maybe 200/300m lower, and I send the Mavic over the crest. The other side is much steeper, and once on the other side, imagine that I loose connexion due to the terrain. A lost connexion will activate the RTH : if my RTH is set to 50m altitude, will it just hit the mountain side, due to its shutting down the sensors in RTH mode ?
I guess the best way to shoot this kind of footage is to find myself at the very top of the crest, were I'll be "visible" for the drone, but sometimes, you just dont have access to the ideal point, and then you send the drone...

Maybe my question is stupid, and there's already a way to avoid bad surprises like this, but I thought it was worse asking...
Thanks !!
 
You're not alone, I too have always wondered about this. Let alone mountains, I always shoot cityscape yet I've got the exact same problem. I wonder if a building stands between the point where I lost connection and the home point, then I hit RTH, will the drone just crash into that building?
It's never happened to me tho.
Lately I've worked this around with always remembering all the path I've flown over, so that when the signal is lost, I just fly back / retreat to the last point where it has signal.
Also considering: the buildings I shoot are over 150m+, some are 200m+, I think it'll drain battery if the drone always has to climb above 200m to return home.
But still... I've always wondered about that... But I'll never crash my drone.
 
Yes, you have to set RTH altitude higher then the mountain peak. The added bonus is that once it climbs it will probably restore your connection, so you have to chance to cancel RTH and fly back yourself.

Scary thing I can tell you. I've flow once around a mountain peak with a tower. I lost signal very fast once on the other side of the peak (the tower interference probably didn't help). Once the signal was restore my drone was RTH aiming right at the tower. Gladly I was able to cancel it and climb. Now I will always double check the set altitude.

A valuable tip from a more experience pilot is to hit the climb stick as soon as possible once you see any interference or signal degradation in a situation like this.
 
Yes, you have to set RTH altitude higher then the mountain peak. The added bonus is that once it climbs it will probably restore your connection, so you have to chance to cancel RTH and fly back yourself.

Scary thing I can tell you. I've flow once around a mountain peak with a tower. I lost signal very fast once on the other side of the peak (the tower interference probably didn't help). Once the signal was restore my drone was RTH aiming right at the tower. Gladly I was able to cancel it and climb. Now I will always double check the set altitude.

A valuable tip from a more experience pilot is to hit the climb stick as soon as possible once you see any interference or signal degradation in a situation like this.

Yes, you have to set RTH altitude higher then the mountain peak. The added bonus is that once it climbs it will probably restore your connection, so you have to chance to cancel RTH and fly back yourself.

Scary thing I can tell you. I've flow once around a mountain peak with a tower. I lost signal very fast once on the other side of the peak (the tower interference probably didn't help). Once the signal was restore my drone was RTH aiming right at the tower. Gladly I was able to cancel it and climb. Now I will always double check the set altitude.

A valuable tip from a more experience pilot is to hit the climb stick as soon as possible once you see any interference or signal degradation in a situation like this.

I've hit the climb stick after signal lost, it took quite a worrisome while before signal was regained. It's much faster to retreat to the last point before signal was lost OR... I've also decided to continue flying til it appeared on the other side of the building. So it's just behind the building that signal is lost. To the left or right of that building signal is fine.
 
I guess in an urban environment it might make more sense to move to the side. In mountains, the path will not be so clean. And you are assuming that you don't have video but have control of the drone. The thing is, you might have neither. In my case, when video was restored the drone was already RTH from the loss of control signal.
 
Hi everyone !
My main playground for my M2 pro is the mountain environment, and since I'm planning to use it in quite high altitude, one thought came to my mind about the RTH function... Someone could give me more details? Here's my question :

Considering a crest that peaks at 3000m altitude, I take off maybe 200/300m lower, and I send the Mavic over the crest. The other side is much steeper, and once on the other side, imagine that I loose connexion due to the terrain. A lost connexion will activate the RTH : if my RTH is set to 50m altitude, will it just hit the mountain side, due to its shutting down the sensors in RTH mode ?
I guess the best way to shoot this kind of footage is to find myself at the very top of the crest, were I'll be "visible" for the drone, but sometimes, you just dont have access to the ideal point, and then you send the drone...

Maybe my question is stupid, and there's already a way to avoid bad surprises like this, but I thought it was worse asking...
Thanks !!
In your example ... starting 200-300m lower than the peak with a RTH altitude ... & this is important, set at 50m above your HP.

I'd say it depends ...

If you from your HP go up over the peak & behind ... it means the drone will be on 200-300m height above your HP, If then the failsafe RTH kicks in the drone will maintain that higher height, not descend & then go home, if clearing the peak at that height it will be a success.

But if you once on the other side of the peak descend below the peak ... it will go home with a height lower then the peak & risks a crash.

The drone will only start the RTH procedure with ascending up to 50m if it's lower than the RTH altitude, if already higher than RTH altitude it will maintain that altitude.
 
  • Like
Reactions: vince-fr
Okay, but now we've got another question : how do you determine the peak's height early on before we get near the peak?
 
Okay, but now we've got another question : how do you determine the peak's height early on before we get near the peak?
Do an initial flight - ascend, and check what your altitude above your take-off point is showing as when the Mavic camera (set horizontal), has the peak centred on your Go4 view. That should be pretty close to showing you how much higher the peak is. You can set RTH parameters while the Drone is flying.
It may not sound sensible - but you can actually use your Mavic, to plan your Mavic's flight ... :cool:
 
  • Like
Reactions: Mossiback and TTP
Do an initial flight - ascend, and check what your altitude above your take-off point is showing as when the Mavic camera (set horizontal), has the peak centred on your Go4 view. That should be pretty close to showing you how much higher the peak is. You can set RTH parameters while the Drone is flying.
It may not sound sensible - but you can actually use your Mavic, to plan your Mavic's flight ... :cool:

Well 1. ain't nobody got battery juice to do initial flight and back down again. Such a waste of battery.
2. When I get to the top I'm usually in the process of doing the drone motion and filming. That's when signal loss usually occurs and thus the need to RTH. [emoji23] Seriously, I circle around a skyscraper from bottom to top (so it gets dramatic view). And you know when it gets to the top and behind the skyscraper, signal is gone. I can't change Rth altitude because I'm in the process of filming.
 
Well 1. ain't nobody got battery juice to do initial flight and back down again. Such a waste of battery.
2. When I get to the top I'm usually in the process of doing the drone motion and filming. That's when signal loss usually occurs and thus the need to RTH. [emoji23] Seriously, I circle around a skyscraper from bottom to top (so it gets dramatic view). And you know when it gets to the top and behind the skyscraper, signal is gone. I can't change Rth altitude because I'm in the process of filming.
I'd rather waste my battery than my Mavic ... That's up to you ...
 
I'd rather waste my battery than my Mavic ... That's up to you ...
Or should we just set up RTH altitude to 600m just to be safe? Ample headspace. Unless you're in Dubai.
And in OP's case 1-3 km? Unless you're in Everest.
 
Or should we just set up RTH altitude to 600m just to be safe?
You always need to have RTH height set to an appropriate level to clear any obstacles that could be between you and the drone.
You have to set that before your flight.
But flying behind towers or mountains is unwise and is just asking for trouble.
 
  • Like
Reactions: BigAl07
Setting a very high RTH altitude will work, but remember that higher altitudes mean higher winds. There are many cases where a high RTH altitude setting led to a situation where the drone gets blown downwind against the direction called for by the RTH function.
 
  • Like
Reactions: BigAl07
Get more batteries, at least one more to gauge the height of the mountain. You can also film during that flight, just not go behind.

You not have to film all-in-one clip. Consider making another trip to get the backside of the mountain, then edit together in post.

You really do not want each scene to be long anyways. A good way to lose viewer engagement is to make the scenes too long -- keep them to 8-20 seconds each before transitioning to a new view, which will keep them interested.

You can program a mission with LITCHI that will not RTH at signal loss. But you have to program that mission, which means knowing all of the POI heights and obstacle locations.

Chris
 
It's also important to note that, when the Mavic 2 loses connection and triggers failsafe RTH, it does not immediately climb to the set RTH height. Its initial response is to retrace its flight track for 60 seconds to attempt to regain uplink. That will usually work if the cause of uplink loss is terrain or structures.

Additionally, even if it doesn't regain uplink and enters full RTH, it will not descend to the set RTH height, so as long as it has not descended on the other side of the ridge then it should be high enough to clear it on the way home.
 
Last edited:
Please remember that in the USA, 400 feet AGL, at the drone's location, is the maximum height limit. Even at that, altitude separation between drone and aircraft is not assured depending on where you are flying. As a general rule, where there are no people of structures, manned aircraft can fly as close to the ground as they like. Listening for aircraft engine noise, as a warning may help, though not always. Gliders often fly ridge if there's wind above 10 knots or so, and they are difficult to spot, make little noise, and "polish the rocks" as we say.
 
The M2P will RTH at the altitude where signal is lost or RTH is requested as long as this is above set RTH altitude. It will not descend until over the home point and landing. In mountains, where I fly a lot, you need to be certain to maintain VLOS... at least don’t descend below an obstruction (mountain top). This is a recipe for drone loss.
 
  • Like
Reactions: PAW and BigAl07
Okay, but now we've got another question : how do you determine the peak's height early on before we get near the peak?


You do some PreFlight Planning... either work out the heights from maps/sectionals or do as advised and PreFly to determine heights.

Doing this type of flying w/o the proper preplanning is almost an assured way to get the opportunity to replace your aircraft at some point.
 
in the RTH menu, there’s “RTH at current altitude” : the drone will maintain The altitude when it lost connection ? In the case of a reveal shot, you don’t get lower than the highest point because you want fly over it...
another question is : if my current altitude is higher than my RTH setup, it should maintain its it and not go down... or am I mistaking ?
 
Lycus Tech Mavic Air 3 Case

DJI Drone Deals

New Threads

Forum statistics

Threads
130,592
Messages
1,554,172
Members
159,596
Latest member
da4o98