I set my Return To Home Altitude to 150 feet
I am flying the Mini 2 at 100 feet AGL
Return to Home is initiated.
    - Mini 2 rises 150 feet, then returns to GPS Home coordinates. Perfect!
or
I am flying the Mini 2 at 350 feet AGL
Return to Home is initiated.
    - Mini 2 doesn't rise at all and simply returns to GPS Home Coordinates. FAil.

Why does the starting altitude affect whether the Mini uses the RTH altitude setting?
Sometimes I'm flying even at 800 feet AGL when I've been climbing over a hill for example and I might literally only be 10 feet over the actual ground, but if the RTH kicks in and it seems it would cause the Mini to rise more than 400 feet higher than the STARTING altitude, it simply will not rise first. This seems a REALLY bad idea. Already cost me my first Mini 1 - smashed into side of cliff as a result.

Am I doing something wrong?


Davo

I could be missing something but I don’t see an issue.
If it’s below the set RTH it will rise to the RTH altitude and return.
If it is flying above the RTH setting it will return at it’s present altitude.
All bets are are off, I believe, if it’s within 50 meters of the home point, then it will return at its current altitude.

Your starting AGL is 0 no matter what your elevation might be.
It does not compensate for actual elevation above sea level.

If you power up your drone at the base of a hill, set your RTH to 300' fly up and over said 800' hill then down the other side and enable RTH,  it will not end well.

I will be corrected if mistaken but I believe that is the way it works (not like in The Shining corrected).

It is up to the operator to determine what RTH altitude is needed for the location. If there is a hill that is 350 feet high and the drone may need return above that, then set the RTH to 400 ft. Use something like a MA2 if you want better obstacle avoidance during RTH.
But if you mean the altitude of the home point, it should reference that level to zero at launch already.

The drone does not descend to the RTH Height it will only elevate.  Best to ensure you have clearance of any objects in the RTH path, so set the RTH Height higher than anything in the area when possible.  Be mindful of altitude restriction.

JohnLietzke Posted at 1-12 15:52
The drone does not descend to the RTH Height it will only elevate.  Best to ensure you have clearance of any objects in the RTH path, so set the RTH Height higher than anything in the area when possible.  Be mindful of altitude restriction.

Two things.
If you are not more than 150 feet from home it will go down where it is at.
The 150 RTH is where you are standing so if it is up a hill 800 feet it is going  straight down to 150 feet above where you are standing. Which means it will go down 650 feet where it is at when you initiate RTH.
I watched a guy do that when he was flying the side of a mountain.
So wherever it’s at you need 150 be able to make sure it can go straight down to the RTH height.

I think I understand what you are saying.  

The HomePoint is a fixed location based on GPS and not the location of the Remote Control is at.

If the drone is within 5-50m (150ft) of the Home Point then it will not change height but simply change direction and return to the Home Point at the current height it was at when the RTH was initiated.   

A practical example, the drone is 75ft away and at height of 50ft.  If you were to initiate an RTH it would stay at 50ft in the air and fly the 75ft to the Home Point then descend to 0ft and land.  But, if you were standing on the ground flying up to the top of a tall building.  The drone is 75ft away and at a hight of 800ft.  When an RTH is initiated the drone will fly at a height of 800ft back to the HomePoint.  Once over the HomePoint it will descend and land.

If the HomePoint is 1,000ft from the previously mentioned building and the drone is flying at 800ft, then it will depend on what the RTH Hight is set at in the DJI Fly app.  If the RTH Height in the DJI Fly app set is to 900ft then the drone will ascend (100ft) to that height and fly at 900ft to the HomePoint and land.  If the RTH Height is set at 400ft the drone will maintain the 800ft height as it flies back to the HomePoint then land.  

If the drone went down below a cliff you were standing on 100ft it would detect that the hight is -100ft and would ascend to the RTH Height set in the DJI Fly app.  So if the RTH Height was set in the DJI Fly app to 400ft the drone would ascend 500ft before flying back to the HomePoint and landing.  According to DJI's phone support if the drones height is below the height of the Home Point it will always ascend to the RTH Height set in the DJI Fly app before flying to the HomePoint and landing.  Support said this may also happen if the drones is less than 2 meters in height from the HomePoint.

Why does the starting altitude affect whether the Mini uses the RTH altitude setting?
It doesn't

Am I doing something wrong?
Yes .. not realising that RTH height, like all heights is relative to Home = zero
Re-read the RTH section of your manual, it's important and quite detailed.

Wonder if it could be possible for dJI To add in the safety section  that would give us the option to return to home at its present height if it’s height is above the RTH height. Then there would not go down to RTH first before returning. And that way it would descend down into the ground..
I may be wrong but it’s just a thought.
Doug

Donut Posted at 1-12 19:00
Wonder if it could be possible for dJI To add in the safety section  that would give us the option to return to home at its present height if it’s height is above the RTH height. Then there would not go down to RTH first before returning. And that way it would descend down into the ground..
I may be wrong but it’s just a thought.
Doug

Hi Doug,

Flying above the RTH height setting and RTH engages ; it will never descend.

cheers
JB

^^^^ Right. The only exception to that is with the Power Saving Return to Home option like in the MA2. But even that is a gradual descent.

JohnLietzke Posted at 1-12 18:09
I think I understand what you are saying.  

The HomePoint is a fixed location based on GPS and not the location of the Remote Control is at.

[I]If the drone went down below a cliff you were standing on 100ft it would detect that the hight is -100ft and would ascend to the RTH Height set in the DJI Fly app.  So if the RTH Height was set in the DJI Fly app to 400ft the drone would ascend 500ft before flying back to the HomePoint and landing.  According to DJI's phone support if the drones height is below the height of the Home Point it will always ascend to the RTH Height set in the DJI Fly app before flying to the HomePoint and landing.  Support said this may also happen if the drones is less than 2 meters in height from the HomePoint.[/I]

This is what I came looking for.

Thanks

djiuser_uvIzjtdw8jDc Posted at 11-27 15:40
If the drone went down below a cliff you were standing on 100ft it would detect that the hight is -100ft and would ascend to the RTH Height set in the DJI Fly app.  So if the RTH Height was set in the DJI Fly app to 400ft the drone would ascend 500ft before flying back to the HomePoint and landing.  According to DJI's phone support if the drones height is below the height of the Home Point it will always ascend to the RTH Height set in the DJI Fly app before flying to the HomePoint and landing.  Support said this may also happen if the drones is less than 2 meters in height from the HomePoint.

This is what I came looking for.

This nuance was resolved in an update many months ago from my understanding.  But I have not tested it again.

The incident stands out to me.  But the issue was that once I descended close to the home points elevation within 500ft the Mavic Air 2 attempted an auto landing.  

Fortunately, I had enough time to cancel it. It was a very close to being swallowed by the ocean.  Probably less than 10 ft.

Sorry newbie here, I hope I am not asking a question that has not already been asked. (even though I thought it must have been).
I have 2 x scenario's that I need clarification around, I will use figures that are probably not realistic but I hope it more easily explains my concern.
1. If I was to launch my drone from my house half way up a hill at 50m above sea level, I have a national restriction of 120m in my country & I have set my RTH at 100m. I then fly my drone towards the sea lowering my altitude as I go & get to a point 10 above sea level. I then lose signal & RTH is activated. Am I correct in believing that my drone would ascend an additional 140m (to reach the RTH altitude of 100m above my start point) and return to home? If so I would be breaching my 120m ceiling by 30m at the start of the return at least. If the drone is restricted to ascending to120m at the location where the signal is lost would it only ascend to 120m above sea level & not attain the 150m above sea level needed to be at 100m above home before descending / landing?
2. In another scenario where I left home and headed to a location where the ground level is 50m above my home location & I am flying at 75m above the ground & the RTH is activated. My understanding is that the drone would RTH at it's present height. When it reaches the location directly above the home position it would be at 125m above ground level & in breach of the 120m restriction. Is this correct.
I appreciate that these scenario's may not be realistic but in my mind the RTH height would be better aligned with ground height. If I was to set it at 100m in either of these scenario's there would be a 20m fudge factor for mapping inaccuracies?
Sorry just read this after I posted it, I am not sure why this is saying I am in Israel. I am in New Zealand.

Germ68 Posted at 2-15 17:03
Sorry newbie here, I hope I am not asking a question that has not already been asked. (even though I thought it must have been).
I have 2 x scenario's that I need clarification around, I will use figures that are probably not realistic but I hope it more easily explains my concern.
1. If I was to launch my drone from my house half way up a hill at 50m above sea level, I have a national restriction of 120m in my country & I have set my RTH at 100m. I then fly my drone towards the sea lowering my altitude as I go & get to a point 10 above sea level. I then lose signal & RTH is activated. Am I correct in believing that my drone would ascend an additional 140m (to reach the RTH altitude of 100m above my start point) and return to home? If so I would be breaching my 120m ceiling by 30m at the start of the return at least. If the drone is restricted to ascending to120m at the location where the signal is lost would it only ascend to 120m above sea level & not attain the 150m above sea level needed to be at 100m above home before descending / landing?

To put things simply ....
The heights the drone uses are all relative to the launch point.
The drone has no knowledge of height above sea level or above ground level.
Your country's rules are all based on height above the ground below the drone.

And your drone will climb to RTH height if it is lower and won't descend to RTH height if it is already higher.

didnt quote who I am answering

Germ68 Posted at 2-15 17:03
Sorry newbie here, I hope I am not asking a question that has not already been asked. (even though I thought it must have been).
I have 2 x scenario's that I need clarification around, I will use figures that are probably not realistic but I hope it more easily explains my concern.
1. If I was to launch my drone from my house half way up a hill at 50m above sea level, I have a national restriction of 120m in my country & I have set my RTH at 100m. I then fly my drone towards the sea lowering my altitude as I go & get to a point 10 above sea level. I then lose signal & RTH is activated. Am I correct in believing that my drone would ascend an additional 140m (to reach the RTH altitude of 100m above my start point) and return to home? If so I would be breaching my 120m ceiling by 30m at the start of the return at least. If the drone is restricted to ascending to120m at the location where the signal is lost would it only ascend to 120m above sea level & not attain the 150m above sea level needed to be at 100m above home before descending / landing?

Qu1) you are correct, the drone would climb 140m and temporarily be in breech of the 120m AGL (Above Ground Level) rule.
Qu2) you are correct the drone would arrive over the home point at 125m AGL.

Your scenarios are not unrealistic at all, they occur all too often. That said unnecessarily high RTH heights wastes power in any unnecessary climb and descent and may put the drone up into strong wind. I set RTH height to clear possible obstacles by around 10m i.e. reset it for every new location.
Providing the drone is not actually executing an RTH you can change the RTH height during a flight.

Labroides Posted at 2-15 23:18
To put things simply ....
The heights the drone uses are all relative to the launch point.
The drone has no knowledge of height above sea level or above ground level.

Thank you, that confirms my belief. So if I am flying around my property which is on a hill and has tree's on it setting a RTH height requires more consideration than just the height above ground level of the tree's & obstacles near the take-off point. That is something I can work with, my biggest problem is more around impinging on the the 120m max ceiling height.

Thank you.

Sean-bumble-bee Posted at 2-16 11:34
Qu1) you are correct, the drone would climb 140m and temporarily be in breech of the 120m AGL (Above Ground Level) rule.
Qu2) you are correct the drone would arrive over the home point at 125m AGL.

Nice answer, thank you. I guess my biggest concern would be around the 2nd scenario. If I had lowered the drone into a clearing & the height above the home point at that instant was close to the 120m ceiling then the chances of hitting a tree / obstacle on the RTH path would be un-nerving.

Lot's to learn.

Thanks again.

You can set the max height at anything up to 500m,  the max RTH height is equal to the set max height. So, if you fly up hill you can raise both to more that 120m, been there done that.
If you lost connection then, providing you aim the controller's antennae correctly, it is quite likely you would get connection back during the climb to RTH height and or the flight home. Once you have connection you can reduce the drone's height during the flight home, been there done that. Just watch that you do not accidentally change one setting/limit whilst intentionally changing the other, been there done that too and it took a llloooonnnngggg time to get the drone down into legal airspace one I had connection back, I have those FLY limit sliders.


JUST MAKE SURE to read the manual and find out if any and what stick actions cancel an on going RTH and what phases of the RTH those stick actions affect.