Sean-bumble-bee Posted at 1-2 05:21
Having produced the following from CsvView I have to own up and say the tail end of the conclusion that I drew in post #10  was wrong. It seems there is something odd happening with the drone, apologies.
I also see I have been gazumped with graphical stuff lol.
If possible I'd be inclined to add the DAT log for the flight to any correspondance sent to DJI.

What are the indicators for propeller icing, I would assume iced propellers would include increase in RPM since it can not cut the air as efficiently, like a boat prop cavitation in water, higher amp draw on the motors due to increased weight loads of ice on the leading edges of the props ?

srdyiop Posted at 1-2 06:07
What are the indicators for propeller icing, I would assume iced propellers would include increase in RPM since it can not cut the air as efficiently, like a boat prop cavitation in water, higher amp draw on the motors due to increased weight loads of ice on the leading edges of the props ?

Agree, more power draw with icing on the blades. (higher revs to comensate less lift)
Not in this flight though.

cheers
JJB

JJB* Posted at 1-2 06:15
Agree, more power draw with icing on the blades. (higher revs to comensate less lift)
Not in this flight though.

[Image]

@JJB can you see any significant differences between this flight and the two I linked earlier where the aircraft stopped climbing mid-flight on the first flight after the Fly Safe DB update?

The only difference I can see is that this flight was conducted mostly below the take of altitude, but the main symptom appears identical - at some point in the flight the aircraft stops responding to climb input unless it is below 0m or thereabouts.

Unfortunately in this case this meant getting home was impossible, in the other two reported cases it just meant that ascent was not possible but getting home was possible as only descent and horizontal manoeuvres were required.

Or am I missing something (I've only read the descriptions as I'm on a small screen at the moment).

No Original Thought Posted at 1-2 06:55
@JJB can you see any significant differences between this flight and the two I linked earlier where the aircraft stopped climbing mid-flight on the first flight after the Fly Safe DB update?

The only difference I can see is that this flight was conducted mostly below the take of altitude, but the main symptom appears identical - at some point in the flight the aircraft stops responding to climb input unless it is below 0m or thereabouts.

Hi,

Had another look, triggerd by your question.

DJI has to give some answers for sure !!

This MINI2 started to climb for  -81 meters baro height, full UP and climbing with 3 m/s up speed.
All normal values (including batt cell values and amps drawn), BUT software did slow down this rate of climb reaching ZERO height.
See the chart. Slowing down smoothly, done by software for some reason!White dotted marking lines where slowing down start.
Chart in #42, see amps go less at the same point.
Check in the chart to UP stick still 100% up, while slowing down the vertical speed up.

Had a look at one of the other log you mentioned, result is the same ; no climb with up cmd.

cheers
JJB

Since I screwed up in post 10 I have just flown this for comparison, mini2,.

Air temp 11C. The descrepancy between the barometer and VPS is due to the drone having been flown up a 'hill'

Your report triggered a memory of the time that I was flying my Mavic Mini inside my church auditorium. It is a tall indoor space. I had flown around inside my house before, but never in a tall building with a high ceiling. I'm trying to remember back, but I believe my GPS connection was lacking due to being indoors. So the drone was flying based on its cameras that look downward. Regardless, I could take off from the floor of the auditorium but I could only go, I would estimate 10 to 15 feet above the floor. The drone would not climb anything beyond that height. So this is making me wonder, if this is somehow related.

JJB* Posted at 1-2 07:24
Hi,

Had another look, triggerd by your question.

So, "software" meaning the software from FlyApp or the software on the drone itself?  I've read a couple posts about the similar issues and their FlyApp are all on 1.5.x , so would that really be the culprit here?  Good findings from your graph.

To safely test this out, those with 1.5.x FlyApp can try launching from the upper level deck and fly around low to the ground, and they should see negative altitude then, right?

EnjoyFlying Posted at 1-2 08:27
So, "software" meaning the software from FlyApp or the software on the drone itself?  I've read a couple posts about the similar issues and their FlyApp are all on 1.5.x , so would that really be the culprit here?  Good findings from your graph.

My guess would be the fly app, let`s wait for DJI to give answers!

Making data visual is often the best way of understanding data and the connection between data fields.

cheers
JJB

Does the Fly Safe database, or some subset of it, get loaded onto the aircraft itself?

The download obviously happens in the fly app, but it would make sense for the aircraft itslef to be aware of, for example, FRZs and max height limits so that even in the event of app/RC disconnect the aircraft will not fly itslef into trouble.

My guess from the other reports similar to this was that the aircraft was processing the Fly Safe DB update and when it activated or became relevent, that is when the aircraft started to refuse to climb.

Again, total guess work, but if the system was switching between old and new data then theoretically a null value could be returned and 8nterprettes as zero. If this was returned internally as a height limit, for example, this could cause the issue seen.

Obviously we dont know the internal working of the aircraft software, but that's a theoretical way this could possibly happen.

That FSDB update seems to be a common factor, though.

Famous Posted at 1-2 08:23
Your report triggered a memory of the time that I was flying my Mavic Mini inside my church auditorium. It is a tall indoor space. I had flown around inside my house before, but never in a tall building with a high ceiling. I'm trying to remember back, but I believe my GPS connection was lacking due to being indoors. So the drone was flying based on its cameras that look downward. Regardless, I could take off from the floor of the auditorium but I could only go, I would estimate 10 to 15 feet above the floor. The drone would not climb anything beyond that height. So this is making me wonder, if this is somehow related.

The indoor or VPS but no GPS 5m ceiling is noted in the manual.
From the manual of the Mavic Mini when discussing the downward looking sensors
".....The max hover altitude of the aircraft is 5 m if there is no GPS. The Vision Syste....."

From the manual of the"2020.11 v1.0  Mini2 Manual
"The aircraft has a max hovering altitude of 5 m if GPS is available.
The Downward Vision System may not fu......."

Spot the difference? lol

The 1.4 manual for the Mini 2 states "The aircraft has a max hovering altitude of 5 m if GPS is unavailable"

No Original Thought Posted at 1-2 09:55
Does the Fly Safe database, or some subset of it, get loaded onto the aircraft itself?

The download obviously happens in the fly app, but it would make sense for the aircraft itslef to be aware of, for example, FRZs and max height limits so that even in the event of app/RC disconnect the aircraft will not fly itslef into trouble.

Since the drone has to be connected in order to update the database, I would believe that it is contained on the drone itself.

Mobilehomer Posted at 1-2 10:05
Since the drone has to be connected in order to update the database, I would believe that it is contained on the drone itself.

Good point...

Does anyone know how big the FSDB download is? That might give an idea of how long it might take the aircraft to process it. Bearing in mind that if the aircraft is processing a DB update while flying you would expect that processing to be a low priority background task as first priority must be keeping the aircraft airborne.

Bashy Posted at 1-2 01:03
I used the 66% and temps from the local airport, there are a few local personal weather stations close by and they are fairly close to the airport give or take, allowing for the quality of both stations they are
somewhere close to the airport data, It's my thing, weather, i own a pro station (Davis VP2+)
One station at North Beach, whilst a cheaper quality station, temps are normally close for this make, humidity you have to allow for +/-10% and it looks like its closer to the minus  for this one

Any cached video from that flight on your device? would like to see the conditions please...

Let me see if I can pull something out... caveats/disclaimers: I have little experience using the DJI Fly app for managing recorded videos/photos (I just pull the memory card and copy videos/photos to my desktop computer -- obviously, not an option for that last flight with the drone stuck in a snowbank down a cliff)....so I might need some handholding....

OK, found about a 5 minute low-res video, showing the climb up from the turnaround point down low by the sailboats, up to (and beyond) the point where it stopped climbing.  You can see it initially climb as expected, but then, some hovering (while I was trying to climb a bit higher), turning around to look for a "Plan B" landing spot, abandoning that idea, again hovering trying to gain another 20 feet altitude, then hunting for a path between the highest treetops to get closer. Video ends before the final approach and crash.

Let me see if I can link the video...

OK, there it is (at least *I* can see it...).

Worth noting: After the crash, when I went to the DJI Fly app, it was showing a short (5-10 second) clip of video of the actual crash itself -- the last few seconds, impact with the brush, tumble, black...).  I no longer see that video.  Is that recoverable from someplace on my iPhone?  If so, a pointer to where I can find it would be appreciated, it might be helpful to anyone troubleshooting.

Thanks for all the investigation, speciulation, analysis, theories and conjecture.  I'm impressed with the amount of data you all have been able to access and pull together.

Sean-bumble-bee Posted at 1-2 10:03
The indoor or VPS but no GPS 5m ceiling is noted in the manual.
From the manual of the Mavic Mini when discussing the downward looking sensors
".....The max hover altitude of the aircraft is 5 m if there is no GPS. The Vision Syste....."

I wonder if this is related to the issue of not climbing.

Famous Posted at 1-2 11:31
I wonder if this is related to the issue of not climbing.

nope, in this flight GPS signals receiving oke.
If this 5 or 30 meter height limit is set by the software than a message is written in the log.

Burstmode Posted at 1-2 10:32
Any cached video from that flight on your device? would like to see the conditions please...

Let me see if I can pull something out... caveats/disclaimers: I have little experience using the DJI Fly app for managing recorded videos/photos (I just pull the memory card and copy videos/photos to my desktop computer -- obviously, not an option for that last flight with the drone stuck in a snowbank down a cliff)....so I might need some handholding....

Hi,

Start a case with DJI support, read my post #44.

This wasn`t your fault, DJI should investigate and imo its a warranty claim.

cheers
JJB

JJB* Posted at 1-2 11:52
Hi,

Start a case with DJI support, read my post #44.

Thank you for your input and for your analysis.  I will attempt to start a case with DJI and see where that leads.

Any suggestions for the best way to contact/approach DJI Support?  I tried that a few days ago (via online chat on the support website) and I could only reach their "pre-sales" support staff.  They told me no post-sales support staff were available because they were too busy (which did not give me a great first impression...).  Chat/email/phone call/carrier pigeon?  Thanks again.

Burstmode Posted at 1-2 10:32
Any cached video from that flight on your device? would like to see the conditions please...

Let me see if I can pull something out... caveats/disclaimers: I have little experience using the DJI Fly app for managing recorded videos/photos (I just pull the memory card and copy videos/photos to my desktop computer -- obviously, not an option for that last flight with the drone stuck in a snowbank down a cliff)....so I might need some handholding....

That's horrible enough to watch without the final 10 second clip... So close... You can feel the tension in the searching.

(Captain Hindsight> It looked like there was a big building to the left on the cliff, below the aircraft height and with an open area in front. Was that ruled out as it was private property and you did not have permission to land there?

Makes me wonder how the law would look upon an emergency landing for safety reasons on private property that you didn't have permission to land on.)

Burstmode Posted at 1-2 10:32
Any cached video from that flight on your device? would like to see the conditions please...

Let me see if I can pull something out... caveats/disclaimers: I have little experience using the DJI Fly app for managing recorded videos/photos (I just pull the memory card and copy videos/photos to my desktop computer -- obviously, not an option for that last flight with the drone stuck in a snowbank down a cliff)....so I might need some handholding....

Thanks friend @ Burst-Mode for the good video. And now you can see that this cliff is not that steep at all. You will definitely come down, secured with a clothesline or thick rope, and rescue the Mini2.

And you've already done everything right.

If you read all the posts that have similar problems with climbing and see a - negative 0 meter display, it can be
seen almost without a doubt that it is due to your previous update of the Fly Zone and / or the update of the DJI Fly
app to iOS 1.5 .0 or 1.5.1 (are you using iOS with an Apple device or Android ??).
That's why I leave version 1.4.8 DJI Fly app on my iPad Mini 6. I also updated the iOS 1.5.1 DJI Fly app on my iPhone 6 plus.
I will do flight tests with both Apple iOS devices soon.

The temperature and other weather conditions (icing of the propellers, total nonsense !!)
have no influence whatsoever on what happened to you in your flight history.

Burstmode Posted at 1-1 21:11
Thanks for the input, @Labroides.  

Battery was topped off and full, removed from the smart charger just a few minutes before I headed out the door (grabbing the freshly-topped-off batteries was literally the last thing I did before I headed out).  Drove less than 5 minutes to the launch point.  Launched the drone no more than 10 minutes from when I walked out the door.  So while the numbers show 89% at launch, I don't know how that battery could have had more juice in it.  Knowing it was cold outside, when I headed out from my home, I stuck two batteries (one of which I used for the last flight) in my coat pocket to keep them from getting chilled.

Not sure why your drone would not climb but it should have with up stick. I have seen many videos where pilots can climb even with critical low battery, and the RTH should climb to the set altitude. Perhaps there was a relatively strong downdraft over the cliff out powering the cene mode climb, maybe sport mode would have been able climb.

Maybe a bug or max altitude reset if you recently updated the fly app? Looks like two others have had similar experience, now I’m worried about flying until this is resolved.

https://forum.dji.com/thread-253288-1-1.html
https://forum.dji.com/thread-253146-1-1.html

djiuser_pzJXMav115XV Posted at 1-2 16:05
Maybe a bug or max altitude reset if you recently updated the fly app? Looks like two others have had similar experience, now I’m worried about flying until this is resolved.

https://forum.dji.com/thread-253288-1-1.html

Perhaps there was a relatively strong downdraft over the cliff out powering the cene mode climb, maybe sport mode would have been able climb.

There was no significant wind, and no downdraft at all (at least that I could tell).  Worth noting, I think: it climbed perfectly well, as it always has, from sea level almost all the way up until it reached approximately "0" altitude.  After that, it would not climb appreciably (it gained then lost a few feet towards the end, but it was not responding to Up stick as it normally does).

It was in "Normal" mode the whole time (I only learned yesterday, on this forum, that the flight "Mode" setting on the controller makes no difference, it only sets the mode to what's requested on the controller if you change the switch while the drone is in flight...or so I am told.  I switched my controller to Cine mode after my first few flights last summer and have not touched the switch since, but as I now understand how things work, it apparently has actually been in "Normal" mode all along).  Maybe switching to Sport mode would have helped, I don't know.

Maybe a bug or max altitude reset if you recently updated the fly app? Looks like two others have had similar experience

Yes, I *did* update the app (and also firmware) shortly before going out to fly it (less than an hour before this flight).  

Yes, I saw the other posts from people who reported something  similar...similar in some ways, but not identical.  I believe my case is  the only one posted where almost the entire flight was at "negative"  altitude, over much lower terrain.  But it does seem interesting that  the failure to respond to Up stick commands happened after the Mini  climbed UP to roughly "0" altitude (I believe that is also true in one  of the other reports, and it's sort of an "edge case" scenario, that  probably wasn't tested exhaustively...most flights don't involve  negative altitudes).

I am hesitant to call something a bug -- I don't know enough about the specific technologies in the mix to make a judgement.  I'm still very new to this.  But reading those other two threads certainly does make me go "hmmmmm..."  What I do know is that I was on the Up stick hard, and for a long time, and it was not gaining altitude. This was so different from my other 60+ flights, where UP stick always made it immediately zoom higher, and very quickly.  This flight experience was completely different.  I could tell something was different (it was not responding to a basic control input), it seemed something was wrong, but I had no idea why it would not gain altitude when I pushed UP stick all the way for so long.  Of course, as it was happening, I had no idea what the cause could be, I was busy, focused on getting it back to a safe landing place -- though ultimately, that was not successful.  As the title of this thread says, my initial guess was that it was just too cold outside.  I'm sure that didn't help (batteries don't like cold) but now it seems there may be other factors.

Cause and Effect, or just a coincidence? I do not know, and frankly I am not qualified to make that call.  It is an interesting speculation, but at this point, it's just that -- speculation.  Anyone who has tried to troubleshoot issues in complex technology knows that one must be careful about jumping to conclusions.  Still...it sure is interesting.

I notice you didnt point the camera down too look for a spot to plonk it, that's by the by, i also notice that it wasn't sunny either so no snow melt with those temps,

Open a ticket with DJI support, tell them exactly what happened.  Mention that it was a calm day weather wise and that your drone failed to climb at X height and having updated prior to going out and mention that other people forum have experienced this after the update, don't open a ticket till recovery has been made though, get the drone 1st, unless you have fly away cover and the drone is inaccessible or lost. Dont bog them down with a 345 page story, Updated drone (give details of the updates now installed),  explain that you flew down to X ft (m) and when you tried to return it wouldnt climb above X ft (m) and it was still below the take off point and ended up crashing because it wouldnt climb higher than the take off point as other have also experienced on the forum, drum that part into them, so mention it a few times. Look, whilst the specs say minimum of 0C, i wouldnt mention temps unless specifically asked for because you do not want them getting tunnel vision on the temps, we can clearly see in the video that its not temp related. They may want to see the video although i dont think it will help them in this case.

Anyone think of out I've missed? or better explaining whats needed?

DAT logs will almost certainly be requested and possible a copy of the txt log too. Make a copy if the DAT before you either sync it or send it.

I have had something similar to this indoors, however I did have good GPS reception (or at least not yellow/weak). Flew it from second story over the terrace to the first floor. If I went below the deck into the red/negative Alt more than 10 ft or so (or where the downward vision system could get a fix on something), I could continue descent  but it would cap out at 15 ft above ground if I tried to bring it back to the second floor - which was pretty much at second floor level but couldn't cross the guard rails (which seems to reflect the warning in the manual). If I reached out with a piece of cardboard and placed it under the mini 2, the downward vision system would boost it up until it got above zero, and then I could continue climb after that with the controller.  My only fix was to update the home point to reset the altitude when it dropped below 0ft.

Again, anecdotal for me only, but it seems when the downward vision system gets a fix on something below 0 ft PA / fix alt, it seems to go squirrely and won't come back up.

Cheers.

Bashy Posted at 1-2 20:07
I notice you didnt point the camera down too look for a spot to plonk it, that's by the by, i also notice that it wasn't sunny either so no snow melt with those temps,

Open a ticket with DJI support, tell them exactly what happened.  Mention that it was a calm day weather wise and that your drone failed to climb at X height and having updated prior to going out and mention that other people forum have experienced this after the update, don't open a ticket till recovery has been made though, get the drone 1st, unless you have fly away cover and the drone is inaccessible or lost. Dont bog them down with a 345 page story, Updated drone (give details of the updates now installed),  explain that you flew down to X ft (m) and when you tried to return it wouldnt climb above X ft (m) and it was still below the take off point and ended up crashing because it wouldnt climb higher than the take off point as other have also experienced on the forum, drum that part into them, so mention it a few times. Look, whilst the specs say minimum of 0C, i wouldnt mention temps unless specifically asked for because you do not want them getting tunnel vision on the temps, we can clearly see in the video that its not temp related. They may want to see the video although i dont think it will help them in this case.

don't open a ticket till recovery has been made though, get the drone  1st, unless you have fly away cover and the drone is inaccessible or  lost...

Thanks for the suggestions on the best approach.

To be clear, I *did* pay for the fly-away coverage, so I have that, but...as I understand it, that's not a universal, always available benefit (that is, you only benefit if they make a judgement that you should)...it's like any insurance, just having a policy doesn't automatically mean you get the benefit, you have to qualify.  I have assumed they would simply tell me to go pound sand because (some reason).  I have no prior experience with DJI, and don't know how 'customer-friendly' they are as a company, how interested they would be in learning more about the multiple reports of issues around inability to climb, versus their obvious short-term business interests in saving a little money by simply denying a claim.  I guess I'll find out.

The drone is still where it crashed, the snow is rapidly melting right now -- it's raining hard here, temeratures are forecast to remain above freezing for many days.  In a few hours time, the snow that the drone ended up in will be all gone, replaced by mud and lots of moisture.  With the snow gone, the drone may stick where it is (stuck in a bush) or it might fall/slide down the cliff.  Honestly, I'm not sure how recoverable it is.  I'll go take another look when the rain stops (late tomorrow).

I figure I will summarize what happened for DJI, then point them to this thread -- there's plenty of details here and much of the work they would need to do is probably already done and posted here.  It's their forum, they might as well take advantage of what's already been posted.

Sean-bumble-bee Posted at 1-2 20:59
DAT logs will almost certainly be requested and possible a copy of the txt log too. Make a copy if the DAT before you either sync it or send it.

Makes sense. I assume I can find the DAT log on the iPhone (as I found the txt log).  Will get that in the morning before I do anything else.  Thanks.

srdyiop Posted at 1-2 06:07
What are the indicators for propeller icing, I would assume iced propellers would include increase in RPM since it can not cut the air as efficiently, like a boat prop cavitation in water, higher amp draw on the motors due to increased weight loads of ice on the leading edges of the props ?

I can't speak for prop icing, however from my rotary wing days a dead giveaway for rotor icing is increasing torque / collective to maintain a given altitude. Usually it is due to the disruption of laminar airflow over the rotor that decreases the efficiency of the rotor, rather than the weight of the ice. It tends to form first at the rotor root as it is spinning slower, and rarely at the tips as they usually fling the ice off.

However, if your rotors are icing, usually you will find other areas icing up as well that are not rotating - such as thin leading edges. Hoar frost would be the first to form, and my guess is on the mini 2 it would be on the front leg supports.

Honestly, I have only had one incident on a flight (in a bell 412) where we had an icing occurrence trying to get vectors during crap weather. We noticed the wire strikes getting frosty, then the requirement for more power to maintain alt. Decided to divert to an alternate away from the weather, where we landed and hangared the aircraft for the night. Was freaky to see that much ice/frost on the leading edges of the main rotor, tail rotor, wire strikes, stabilizer leading edges, etc.  

Burstmode Posted at 1-2 21:46
Makes sense. I assume I can find the DAT log on the iPhone (as I found the txt log).  Will get that in the morning before I do anything else.  Thanks.

Yes they should be in the folder "MCDatFlightRecords" or something like that and MCDatFlightRecords should be in the folder where you found the txt log, which might have been "FlightRecord".

I haven't backed up logs from an iphone in a while but I think I had to copy the entire FlightRecord folder to the computer, if correct that should also copy the MCDatFlightRecords folder and its contents to your computer.

davidw963 Posted at 1-2 21:42
I have had something similar to this indoors, however I did have good GPS reception (or at least not yellow/weak). Flew it from second story over the terrace to the first floor. If I went below the deck into the red/negative Alt more than 10 ft or so (or where the downward vision system could get a fix on something), I could continue descent  but it would cap out at 15 ft above ground if I tried to bring it back to the second floor - which was pretty much at second floor level but couldn't cross the guard rails (which seems to reflect the warning in the manual). If I reached out with a piece of cardboard and placed it under the mini 2, the downward vision system would boost it up until it got above zero, and then I could continue climb after that with the controller.  My only fix was to update the home point to reset the altitude when it dropped below 0ft.

Again, anecdotal for me only, but it seems when the downward vision system gets a fix on something below 0 ft PA / fix alt, it seems to go squirrely and won't come back up.

This is very good tips , did u rrset Hone Point to RC location or Drone location, and that would reset the drones altitude?  Great info, interesting.

EnjoyFlying Posted at 1-2 22:27
This is very good tips , did u rrset Hone Point to RC location or Drone location, and that would reset the drones altitude?  Great info, interesting.

If i was to make an educated guess, i would say to the drone's position, 1, because it was the controller's position that was the issue in the 1st place but more importantly 2, the controller's position is higher than the drone, but then what do i know lol....

EnjoyFlying Posted at 1-2 22:27
This is very good tips , did u rrset Hone Point to RC location or Drone location, and that would reset the drones altitude?  Great info, interesting.

Several irrelevant guesses are appearing this thread lately from people who haven't looked at the flight data.

did u rrset Hone Point to RC location or Drone location, and that would reset the drones altitude?
1.  He didn't reset the homepoint
2.  Resetting the homepoint does not reset the zero altitude, so would have made no difference

davidw963 Posted at 1-2 21:42
I have had something similar to this indoors, however I did have good GPS reception (or at least not yellow/weak). Flew it from second story over the terrace to the first floor. If I went below the deck into the red/negative Alt more than 10 ft or so (or where the downward vision system could get a fix on something), I could continue descent  but it would cap out at 15 ft above ground if I tried to bring it back to the second floor - which was pretty much at second floor level but couldn't cross the guard rails (which seems to reflect the warning in the manual). If I reached out with a piece of cardboard and placed it under the mini 2, the downward vision system would boost it up until it got above zero, and then I could continue climb after that with the controller.  My only fix was to update the home point to reset the altitude when it dropped below 0ft.

Again, anecdotal for me only, but it seems when the downward vision system gets a fix on something below 0 ft PA / fix alt, it seems to go squirrely and won't come back up.

it seems when the downward vision system gets a fix on something below 0 ft PA / fix alt, it seems to go squirrely and won't come back up.
This also is irrelevant.
It's poor programming by DJI, but it will only affect a drone that has lost GPS.
The OP was out in the open with full GPS for the whole flight.

djiuser_pzJXMav115XV Posted at 1-2 15:49
Not sure why your drone would not climb but it should have with up stick. I have seen many videos where pilots can climb even with critical low battery, and the RTH should climb to the set altitude. Perhaps there was a relatively strong downdraft over the cliff out powering the cene mode climb, maybe sport mode would have been able climb.

Perhaps there was a relatively strong downdraft over the cliff out powering the cine mode climb, maybe sport mode would have been able climb.
Wind hitting a slope would cause an updraft rather than a downdraft.
If the drone had trouble with an imaginary downdraft, it would not sit level, holding altitude when the left stick was pushed up.


Maybe a bug or max altitude reset
His Max Height Limit was set at 400 ft and not changed

Burstmode Posted at 1-2 10:32
Any cached video from that flight on your device? would like to see the conditions please...

Let me see if I can pull something out... caveats/disclaimers: I have little experience using the DJI Fly app for managing recorded videos/photos (I just pull the memory card and copy videos/photos to my desktop computer -- obviously, not an option for that last flight with the drone stuck in a snowbank down a cliff)....so I might need some handholding....

What was wrong with this landing spot ??

Exactly ... what @BMj says.

It's not that steep either and there are enough trees there to tie up with a rope and rescue the crashed drone,
the pilot knows where it is.

Whether or not it is private property might be a consideration. EDIT
Given the house's unobstructed view over the water etc. i.e. no trees blocking the view, I would be inclined to think it is private land.

The drop-off there actually is quite steep, at least the upper part -- it's nearly vertical right below the cliff top, where the drone crashed (otherwise, I would have gone right after it).  The drone is not very far down (at least before the snow melted -- it may still be in the same spot, or could have washed/tumbled lower -- we have had a LOT of snow, followed by steady, hard rain).  Climbing down would/will require rope, some skill, and patience.  The snow is mostly gone now, but everything is soaking wet, with more heavy rain coming.  I will re-evaluate when conditions improve.  Of course, in June or July when things finally dry out (very wet climate here), hiking up from below would probably be fairly easy.  At this time of year, a lot more of an adventure.

As for those structures you see off to the left side of the cliff face: they are multi-million-dollar homes, very much private property and not accessible unless you know the owners (I do not).  The expression "million dollar views" applies here (actually, in this case, more like 2 or 3 million dollar views...).  Some of those folks do not take kindly to surprise, drop-in visits from strangers.

Burstmode Posted at 1-3 19:19
The drop-off there actually is quite steep, at least the upper part -- it's nearly vertical right below the cliff top, where the drone crashed (otherwise, I would have gone right after it).  The drone is not very far down (at least before the snow melted -- it may still be in the same spot, or could have washed/tumbled lower -- we have had a LOT of snow, followed by steady, hard rain).  Climbing down would/will require rope, some skill, and patience.  The snow is mostly gone now, but everything is soaking wet, with more heavy rain coming.  I will re-evaluate when conditions improve.  Of course, in June or July when things finally dry out (very wet climate here), hiking up from below would probably be fairly easy.  At this time of year, a lot more of an adventure.

As for those structures you see off to the left side of the cliff face: they are multi-million-dollar homes, very much private property and not accessible unless you know the owners (I do not).  The expression "million dollar views" applies here (actually, in this case, more like 2 or 3 million dollar views...).  Some of those folks do not take kindly to surprise, drop-in visits from strangers.

Our home is on the waterfront and at first glance it may look like multi-million dollar property but that is far from reality. Still...once a guy with a remote control in his hand appeared and asked if he could come onto the property. His RC sailboat had gone awry and failed to respond to his commands and he wanted a better position. I went even farther and took him out in my boat to retrieve his boat. Sometimes you get lucky.

Yes, sometimes you do get lucky and people may be surprisingly helpful.  Not always (FWIW, there is a lot of anti-drone hostility around here).  As for the home values, I know the neighborhood; home prices are absolutely insane.  The property circled in the image above is currently valued at over $3 million and would probably sell quickly for a lot more than that, in a bidding war.  And there are other homes nearby that would be much higher.  I have to admit, it *is* a nice neighborhood, and those houses do have incredible views.