Hey everyone,

I’m posting here because DJI Support has been unable to provide a clear explanation for my drone’s crash, and I’d love to hear insights from the community.

I overlayed my stick inputs with the drone fly-away footage and provided the logs from AirData here: https://www.dropbox.com/scl/fo/cgj6y37pdg0rljoo35pap/AH0d9Vz-nVFOwTSQ5cy2wPE?rlkey=xk9s5jfwxumdgthejrhvywdn8&st=t9kj4h1x&dl=0

Flight conditions

I was flying my DJI Air 2S over open water with weak satellite positioning and in sport mode. About 1 minute and 10 seconds into the flight, my drone unexpectedly lost about 40 feet of altitude and crashed into the ocean rapidly, completely ignoring my manual throttle-up input through the whole descent.

• No obstacles were present, I was flying 40ish feet above open water.

• I did NOT let go of the sticks or descend intentionally - the drone simply ignored my throttle-up command and dropped into the ocean.

• The DJI flight logs indicate weak GPS throughout the flight, but signal strength was strong (100% uplink/downlink) meaning my throttle up command should have worked and avoided a crash. I have no problem flying the drone manually and have flown in ATTI mode before with no issues.

• DJI’s support response blames weak GPS/ATTI mode, but the manual only describes ATTI mode causing horizontal drifting, not altitude loss: “The aircraft automatically changes to Attitude mode when Vision systems are unavailable or disabled and when the GNSS signal is weak or the compass experiences interference. In ATTI mode, the aircraft may be more easily affected by its surroundings. Environmental factors, such as wind, can result in horizontal shifting, which may present hazards, especially when flying in confined spaces.”

Questions:

1. Should a drone in ATTI mode / Sport Mode lose altitude uncontrollably? The manual states that ATTI mode results in drifting due to wind but does not mention loss of altitude. The footage suggests an abnormal lurch, with the propeller entering the field of view, as if the drone lost stability mid-flight and then promptly flys in reverse and descending while I input forward and throttle up.

2. Does Sport Mode impact altitude control? I understand that Sport Mode disables obstacle avoidance and increases braking distance, but does it have any effect on altitude hold? If so, where is this documented?

3. Has anyone else experienced a similar incident? If this is something that can happen without warning, pilots need to be aware of it, as it is not addressed in the manual.

4. In the case of sport mode / weak GPS, is the drone unable to balance itself?

Any insights, explanations, or similar experiences would be greatly appreciated!

Thanks in advance.

I overlayed my stick inputs with the drone fly-away footage and provided the logs from AirData here:

What would be much more helpful is to post the recorded flight data.
Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report you can post a link for the report here.

Or if you use Airdata, post a link to the Airdata report for the flight, making sure you've ticked the Share box..

Or just post the .txt file.

If you used the RC controller, you'll find your files here:
Android\data\dji.go.v5\files\FlightRecord

Hopefully this is readable for you. Alternatively, check out the dropbox link I provided - the pdf of the log is in there.

1. Should a drone in ATTI mode / Sport Mode lose altitude uncontrollably?
No .. in Atti Mode or Sport Mode, your drone will still have height holding ability but it won't have the ability to hold horizontal position.
Lack of GPS won't make a drone lose altitude uncontrollably.

2. Does Sport Mode impact altitude control?
No.
In Sport Mode the drone is allowed to tilt further and so fly faster.
It has no effect on height holding

3. Has anyone else experienced a similar incident?
It would be necessary to see your flight data to understand what actually happened.

4. In the case of sport mode / weak GPS, is the drone unable to balance itself?
Whether in Sport Mode or Atti Mode the drone is perfectly able to maintain proper balance.

Let's see that data to work out what happened.
It might also help to copy and paste the report from DJI's analysis.

djiuser_pyp5R4G06XsB Posted at 3-18 16:35
[view_image]

Hopefully this is readable for you. Alternatively, check out the dropbox link I provided - the pdf of the log is in there.

A picture of one page of the Airdata summary won't help.
I'd need to see the actual data.

Tick the Share box in Airdata and send a link to the Airdata report and I can get the data from there.

Labroides Posted at 3-18 16:42
A picture of one page of the Airdata summary won't help.
I'd need to see the actual data.

Here you go mate: https://app.airdata.com/share/wujaQO

Lmk your thoughts

Labroides Posted at 3-18 16:40
1. Should a drone in ATTI mode / Sport Mode lose altitude uncontrollably?
No .. in Atti Mode or Sport Mode, your drone will still have height holding ability but it won't have the ability to hold horizontal position.
Lack of GPS won't make a drone lose altitude uncontrollably.

Sent the same thing to the other user, here you go! https://app.airdata.com/share/wujaQO

Excited to hear your thoughts.

djiuser_pyp5R4G06XsB Posted at 3-18 16:45
Here you go mate: https://app.airdata.com/share/wujaQO

Lmk your thoughts

Thanks ... that's good.
It might take a while, but I'll get back when I have something for you.

djiuser_pyp5R4G06XsB Posted at 3-18 16:45
Here you go mate: https://app.airdata.com/share/wujaQO

Lmk your thoughts

You launched without GPS and flew for 30 seconds before it was able to record a home point.
Can you give me a rough idea how high above water level your takeoff position was?

Labroides Posted at 3-18 16:55
You launched without GPS and flew for 30 seconds before it was able to record a home point.
Can you give me a rough idea how high above water level your takeoff position was?

Rough estimate of takeoff elevation was about 43 meters / 130 feet. Looks like the drone estimated between -10 and -20 meters throughout the flight.

djiuser_pyp5R4G06XsB Posted at 3-18 17:02
Rough estimate of takeoff elevation was about 43 meters / 130 feet. Looks like the drone estimated between -10 and -20 meters throughout the flight.

I've got to go out for an hour or so .... check back later

djiuser_pyp5R4G06XsB Posted at 3-18 17:02
Rough estimate of takeoff elevation was about 43 meters / 130 feet. Looks like the drone estimated between -10 and -20 meters throughout the flight.

The GPS is an obvious concern.
You launched prematurely, but that shouldn't cause any issues other than recording the homepoint well out from where you launched.
But your GPS is receiving significantly lower numbers of sats than would be expected out in the open with a 360° unobstructed skyview.
Sat numbers eventually reached 15 but they probably weren't in a good spread over the sky as the GPS data quality kept blinking out and dropping to 2/5.
The drone requires GPS data quality of 4/5 or better for full GPS reception.

Earlier in the flight the drone was responding to the throttle correctly and climbing when you pushed the left stick forwards.
But from 1:12.6 the drone descended with the left stick pushed forwards.

In the 2nd last line of data at 1:16.0, there is a warning message saying there is a Compass Error.
It is very unusual to see this at this point in the flight.
Closer examination of the drone's heading data indicates that the drone had been unable to hold its heading from 1:07.9 and had been slowly rotating anti-clockwise without any corresponding rudder input.
Around 1:11.1 the rotating sped up and became erratic in speed and at 1:14.1, it reversed direction.
The pitch and roll data suggests the drone was wobbling and at 1:16.0 the drone rolled hard to the left, signal was lost and the drone and fell uncontrollably.
It looks like the drone lost power before hitting the water.

The compass error points to the instability you described.
Not having good GPS reception is a concern but did not cause the incident.

Hello! Thank you for bringing this up to us and we apologize for the inconvenience this has caused. Could you please provide us with a relevant ticket number (starts with CAS)? We will look into this.

DJI Gamora Posted at 3-18 18:58
Hello! Thank you for bringing this up to us and we apologize for the inconvenience this has caused. Could you please provide us with a relevant ticket number (starts with CAS)? We will look into this.

Hi - thank you for your reply. The case number is CAS-20863492-J8K3S3

I have requested this to be escalated to a supervisor as there was not a sufficient investigation into the crash, and my support person seems uninterested in providing further clarification.

Labroides Posted at 3-18 17:56
The GPS is an obvious concern.
You launched prematurely, but that shouldn't cause any issues other than recording the homepoint well out from where you launched.
But your GPS is receiving significantly lower numbers of sats than would be expected out in the open with a 360° unobstructed skyview.

Hi Labroides,

Thank you very much for looking into this. This is exactly what I have been trying to portray to my case manager / support contact. He has been stonewalling me with generic vague answers that are contradictory to the flight. He’s even been borderline rude - see last note he sent me earlier “ Hello,
Sir did you read the manual? There are other outlines stated there that does answer your questions. Are you disputing the facts?”. Felt like I was being gaslit!

DJI’s findings were “weak gps” which I did not agree with. My drone is out of warranty, but I would very much like a proper ruling so I can determine what to avoid in the future with a more professional / commercial drone.

In the logs, my flight was 1:16 long, and the compass error / hard left / signal lost occurred at 1:16. I think the compass error occurred because of the crash into the ocean. The footage from the incident shows water around the drone which makes me think the drone still had power.

djiuser_pyp5R4G06XsB Posted at 3-18 20:01
Hi - thank you for your reply. The case number is CAS-20863492-J8K3S3

I have requested this to be escalated to a supervisor as there was not a sufficient investigation into the crash, and my support person seems uninterested in providing further clarification.

Thank you for providing us with the case number. We have forward this to our team and please rest assured, our team will get back to you via email.

DJI Gamora Posted at 3-18 21:31
Thank you for providing us with the case number. We have forward this to our team and please rest assured, our team will get back to you via email.

Thank you!

djiuser_pyp5R4G06XsB Posted at 3-18 21:45
Thank you!

You're welcome and we appreciate your understanding.

djiuser_pyp5R4G06XsB Posted at 3-18 20:17
Hi Labroides,

Thank you very much for looking into this. This is exactly what I have been trying to portray to my case manager / support contact. He has been stonewalling me with generic vague answers that are contradictory to the flight. He’s even been borderline rude - see last note he sent me earlier “ Hello,

I suggested that the data ended with the drone well above the water based on your launch point being >100 feet above the water and the data ending with the drone approximately 40 feet lower than the launch point.

I forgot to add that in the last two seconds of the flight, the drone did respond to your throttle input by climbing 20 ft.

Labroides Posted at 3-18 22:10
I suggested that the data ended with the drone well above the water based on your launch point being >100 feet above the water and the data ending with the drone approximately 40 feet lower than the launch point.

I forgot to add that in the last two seconds of the flight, the drone did respond to your throttle input by climbing 20 ft.

I very much appreciate the clarification. Regardless, will have to circle back with the support team for further investigation.

From the video playback, it looks like it ascended slightly about 4 or 5 seconds before impact, then warbled about 2 seconds before impact, then promptly dropped out of the sky. Not sure if that lines up with the logs. Whole thing just seems goofy with things not adding up. Hopefully will have answers soon.

Super super appreciative of your input regardless. If I can buy you a coffee or anything please shoot me a pm with your Venmo info.

djiuser_pyp5R4G06XsB Posted at 3-18 22:15
I very much appreciate the clarification. Regardless, will have to circle back with the support team for further investigation.

From the video playback, it looks like it ascended slightly about 4 or 5 seconds before impact, then warbled about 2 seconds before impact, then promptly dropped out of the sky. Not sure if that lines up with the logs. Whole thing just seems goofy with things not adding up. Hopefully will have answers soon.

No worries .. I just enjoy solving flight incident puzzles

djiuser_pyp5R4G06XsB Posted at 3-18 22:15
I very much appreciate the clarification. Regardless, will have to circle back with the support team for further investigation.

From the video playback, it looks like it ascended slightly about 4 or 5 seconds before impact, then warbled about 2 seconds before impact, then promptly dropped out of the sky. Not sure if that lines up with the logs. Whole thing just seems goofy with things not adding up. Hopefully will have answers soon.

Hi,

In addition to Labroides analysis ; last 2 records show drone attitude roll 136 and 101 degrees.
So last records dropping down to the water not in the log.Reason as in the log "Aircraft not connected to RC | RC not connected to mobile device"

Few seconds before last record baro height minus 20 meter, last records minus 12 meter.Height above sea last record approx 30 meter. (from your "Rough estimate of takeoff elevation was about 43 meters / 130 feet").

But video shows drone 'landed' in water, with a normal flying attitude. So i do not understand the last recorded data shows these roll attitude values.
See my charts of your data.

Uncontrolled Yaw started at 1m2s in flight.
Interested to know how DJI will react all this.


btw   flying away above sea without a HomePoint set at takeoff is a good idea. HP was set at sea....
cheers
JJB

Certainly alot to intake here, lots of odd behavior in the drone but one very strong message here is to never leave your launch area without first allowing the drone to set the home point. if the controller ever disconnects that would be your lifeline (always make sure that you have return to home set not "hover" in the menu) Another thing to watch out for is birds in the area, a bird strike will often disable the drone and it will fall out of the sky.
In your case Its not clear what happened.

Can you retrieve and provide the .DAT log for this flight? Look here to see how to retrieve it.

  

https://mavicpilots.com/threads/mavic-flight-log-retrieval-and-analysis-guide.78627/

  

-à 3. Log File Retrieval

  

  -à Mobile device DAT files (DJI GO 4 & DJI Fly)

  

  

The .DAT we’re looking for will have the label YYYY-MM-DD-HH-MM-SS_FLY079.DAT

  

  

I don’t have a lot of experience with Air2S .DAT logs. But, there is a history of DJI drones using the vision system data to determine velocities. This can be problem over water. Also, there could be a partial propulsion issue. The .DAT will let us look at the relevant data.

  

JJB* Posted at 3-19 02:22
Hi,

In addition to Labroides analysis ; last 2 records show drone attitude roll 136 and 101 degrees.

Hi JJB,

Cheers for the further analysis - these logs are awesome and I love the raw data - had no idea this info was able to be analyzed like this. What program / site are the charts from? Available on AirData?

As you pointed out, the drone was flying "nominally" per the video (not flying upside down like the roll of 101-136 suggests in the logs). I wonder if the gyro failed majorly, or as the records suggest, perhaps an issue with the compass?

This is where my technical ability is limited, but I am still intrigued as to what the takeaway will be from DJI.

Regarding RTH and HP, definitely a good idea to set it from my takeoff point. This just happened to be a quick flight (at least I planned it to be one!) and I was confident in my ability to bring the aircraft back no problem. Good to be more mindful of this in the future though!

Tonyvdb Posted at 3-19 05:14
Certainly alot to intake here, lots of odd behavior in the drone but one very strong message here is to never leave your launch area without first allowing the drone to set the home point. if the controller ever disconnects that would be your lifeline (always make sure that you have return to home set not "hover" in the menu) Another thing to watch out for is birds in the area, a bird strike will often disable the drone and it will fall out of the sky.
In your case Its not clear what happened.

Hey Tony,

Agreed regarding the odd behavior of the aircraft. I concur with your Home Point comment - as I said in to JJB, I had planned on this being a quick flight, but that ended up not being the case.

There are a few birds in the area (I'm talking like I've seen two or three in the last three weeks), and the species nearby are not very aggressive IMO. I've been dive-bombed by seagulls in Santa Cruz, but in this location I have never had an experience like that.

Thank you for the input.

BudWalker Posted at 3-19 06:22
Can you retrieve and provide the .DAT log for this flight? Look here to see how to retrieve it.  https://mavicpilots.com/threads/mavic-flight-log-retrieval-and-analysis-guide.78627/  -à 3. Log File Retrieval    -à Mobile device DAT files (DJI GO 4 & DJI Fly)     The .DAT we’re looking for will have the label YYYY-MM-DD-HH-MM-SS_FLY079.DAT     I don’t have a lot of experience with Air2S .DAT logs. But, there is a history of DJI drones using the vision system data to determine velocities. This can be problem over water. Also, there could be a partial propulsion issue. The .DAT will let us look at the relevant data.

Hi BudWalker,

I've uploaded the file to my Dropbox - please let me know if you need anything further: https://www.dropbox.com/scl/fi/uw3drgsuxozoigq0g4sgt/2025-03-06_18-36-11_FLY079.DAT?rlkey=je4uxuy9qcmv0ra1hvpde7xfc&st=zgjsa49o&dl=0

Labroides Posted at 3-18 22:10
I suggested that the data ended with the drone well above the water based on your launch point being >100 feet above the water and the data ending with the drone approximately 40 feet lower than the launch point.

I forgot to add that in the last two seconds of the flight, the drone did respond to your throttle input by climbing 20 ft.

Hi Labroides,

I matched a screenshot of my in-app records with the elevation map. Best estimate I can give of takeoff height is 98.5 feet on the low end, and 105.4 feet on the high end. Still doesn't add up with the logs.

djiuser_pyp5R4G06XsB Posted at 3-19 08:50
Hi JJB,

Cheers for the further analysis - these logs are awesome and I love the raw data - had no idea this info was able to be analyzed like this. What program / site are the charts from? Available on AirData?

Hi,

I some think the data in not correct, data does not match the attitude of your drone at all.
Guess same for the compass heading, not how your drone was flying.

AFAIK a compass error does not interfere with the attitude pitch and roll of a drone.

See my chart of the compass heading, the other line is a reference to the compass, normally the move in the same direction.Looks like the compass indication changed, no the actual heading.

Charts are made with my FRAP program.

cheers
JJB  [ Charts by FRAP ; the 'best' software for data and visual flightlog analysis (www.jjbfrap.eu) ]

JJB* Posted at 3-19 11:51
Hi,

I some think the data in not correct, data does not match the attitude of your drone at all.

Thanks again JJB. Yea, something must have gone catastrophically wrong somewhere within the software stack or there was a hardware issue. Super strange that there were no warnings other than the compass / impact warning. Seems like it just lost its sense of where it was at in space and perhaps in an attempt to save itself, overrode my input and flew straight down.

If I was a windows user and had more logs to analyze than this one incident, would definitely grab your software. Great job.

DJI Gamora Posted at 3-18 22:01
You're welcome and we appreciate your understanding.

Hi, just checking in on the status of this. Any updates?

JPSfilms Posted at 3-19 16:17
Hi, just checking in on the status of this. Any updates?

Hi, thank you for checking in. The issue has been escalated to our relevant team. We appreciate your patience and will keep you updated on any progress. Thank you!

djiuser_pyp5R4G06XsB Posted at 3-19 09:05
Hi BudWalker,

I've uploaded the file to my Dropbox - please let me know if you need anything further: https://www.dropbox.com/scl/fi/uw3drgsuxozoigq0g4sgt/2025-03-06_18-36-11_FLY079.DAT?rlkey=je4uxuy9qcmv0ra1hvpde7xfc&st=zgjsa49o&dl=0

I've been looking at the .DAT but don't have much to show for it. There are a few more things to check out. Did DJI request the .DAT?

Completely out of my depth here, but

Was this place you were flying anywhere near a Department of Defense activity, especially an Air Defense post? You notice anyone observing you flying? Any aircraft in the area warnings?

BudWalker Posted at 3-20 07:13
I've been looking at the .DAT but don't have much to show for it. There are a few more things to check out. Did DJI request the .DAT?

They requested the flight records folder which contains both the .TXT files and the .DAT files. I provided it to them. Seems they should be able to run an analysis the same way Labroides / JJB have done, and either have not done so or have not investigated thoroughly.

High_Order Posted at 3-20 09:17
Completely out of my depth here, but

Was this place you were flying anywhere near a Department of Defense activity, especially an Air Defense post? You notice anyone observing you flying? Any aircraft in the area warnings?

There are military bases on the island, but the closest one is over 15 miles away.

There are a variety of tour buses, surfers, and people walking around by where I took off - so, people glancing in my direction, yes. But, no one actively observing me as far as I could tell. I'm also focused mainly on flying during this flight.

No aircraft warnings.

JJB* Posted at 3-19 11:51
Hi,

I some think the data in not correct, data does not match the attitude of your drone at all.

Hi JJB - I was assigned a new (much more helpful and professional) case manager. I heard back from him today after he was familiarized with the case and reviewed it with his coworkers. Wanted to provide you with a quick update; any insights would be much appreciated:

"So, regarding the loss of altitude from reviewing your case and speaking to my colleagues, it looks like the cause was unfortunately a combination of factors. The first one is that you were flying in an environment with low/weak GPS signal strength, which will cause the unit to drift. While not as stable, this is where the unit relies on its sensors (vision system, barometer, IMU, etc.) to maintain balance.

Unfortunately though, in your case, your unit was not able to do that effectively (relatively speaking) because the unit was over water (the second factor), and the Vision Systems cannot work properly over water. When the vision system is unavailable, that is where the unit relies on the IMU and barometer.

However, the third factor is that you took off from a boat it seems, which was possibly flat, but not steady due to the water. We advise against taking off from any object that is not both flat and steady, because it will affect the IMU and barometer. The IMU helps the aircraft understand its movement and orientation, while the barometer helps it know and control its altitude. If these are off, the aircraft will make incorrect adjustments to its orientation and direction, causing it not to follow the intended flight path.

The combination of these factors is why you experienced the unfortunate situation and why the aircraft was drifting and not following its flight path despite your inputs."

I did not take off from a boat / water, I took off from solid land. Here is my response below:

"I hope you’ve been well, and thank you again for taking the time to look into this

You mentioned the takeoff point being “not steady due to the water” - I wanted to clarify that the drone was launched from solid land, approximately 80–103 feet above sea level. Because of the higher elevation at launch, the drone displayed negative altitude readings during flight. If I had taken off from sea level, those altitude numbers would suggest the drone was flying underwater, which obviously wasn’t the case.

I believe the confusion about the takeoff point may be due to the home point being set while the drone was already airborne over the water, as I was not able to acquire GPS lock prior to takeoff. That would explain why the home point appears offshore, even though the drone physically took off from land.

Is the statement about an unstable takeoff point based on that GPS-derived home point location, or is there actual telemetry or sensor data that suggests instability at takeoff? If so, I’d be very interested in reviewing that.

To summarize my understanding of your explanation:

1. A weak GPS signal triggered ATTI mode, causing the drone to drift.

2. The vision system became unreliable due to flying over water, causing the drone to rely solely on the IMU and barometer.

3. If the takeoff was unstable, the IMU/barometer might have been thrown off, resulting in erratic flight behavior.

However, since I launched from land, I’m trying to understand what could have caused the IMU or barometer to misbehave. Were there any logged errors or performance issues related to those systems? Was there data supporting an unstable launch?

Thanks again for your time - I appreciate your continued support and communication."

Labroides Posted at 3-18 22:35
No worries .. I just enjoy solving flight incident puzzles

Hi Labroides, copying my update to JJB below. Wanted to update you too:
- I was assigned a new (much more helpful and professional) case manager. I heard back from him today after he was familiarized with the case and reviewed it with his coworkers. Wanted to provide you with a quick update; any insights would be much appreciated:

"So, regarding the loss of altitude from reviewing your case and speaking to my colleagues, it looks like the cause was unfortunately a combination of factors. The first one is that you were flying in an environment with low/weak GPS signal strength, which will cause the unit to drift. While not as stable, this is where the unit relies on its sensors (vision system, barometer, IMU, etc.) to maintain balance.

Unfortunately though, in your case, your unit was not able to do that effectively (relatively speaking) because the unit was over water (the second factor), and the Vision Systems cannot work properly over water. When the vision system is unavailable, that is where the unit relies on the IMU and barometer.

However, the third factor is that you took off from a boat it seems, which was possibly flat, but not steady due to the water. We advise against taking off from any object that is not both flat and steady, because it will affect the IMU and barometer. The IMU helps the aircraft understand its movement and orientation, while the barometer helps it know and control its altitude. If these are off, the aircraft will make incorrect adjustments to its orientation and direction, causing it not to follow the intended flight path.

The combination of these factors is why you experienced the unfortunate situation and why the aircraft was drifting and not following its flight path despite your inputs."

I did not take off from a boat / water, I took off from solid land. Here is my response below:

"I hope you’ve been well, and thank you again for taking the time to look into this
You mentioned the takeoff point being “not steady due to the water” - I wanted to clarify that the drone was launched from solid land, approximately 80–103 feet above sea level. Because of the higher elevation at launch, the drone displayed negative altitude readings during flight. If I had taken off from sea level, those altitude numbers would suggest the drone was flying underwater, which obviously wasn’t the case.
I believe the confusion about the takeoff point may be due to the home point being set while the drone was already airborne over the water, as I was not able to acquire GPS lock prior to takeoff. That would explain why the home point appears offshore, even though the drone physically took off from land.
Is the statement about an unstable takeoff point based on that GPS-derived home point location, or is there actual telemetry or sensor data that suggests instability at takeoff? If so, I’d be very interested in reviewing that.
To summarize my understanding of your explanation:
1. A weak GPS signal triggered ATTI mode, causing the drone to drift.
2. The vision system became unreliable due to flying over water, causing the drone to rely solely on the IMU and barometer.
3. If the takeoff was unstable, the IMU/barometer might have been thrown off, resulting in erratic flight behavior.
However, since I launched from land, I’m trying to understand what could have caused the IMU or barometer to misbehave. Were there any logged errors or performance issues related to those systems? Was there data supporting an unstable launch?
Thanks again for your time - I appreciate your continued support and communication."

JPSfilms Posted at 3-27 15:56
Hi Labroides, copying my update to JJB below. Wanted to update you too:
- I was assigned a new (much more helpful and professional) case manager. I heard back from him today after he was familiarized with the case and reviewed it with his coworkers. Wanted to provide you with a quick update; any insights would be much appreciated:

"So, regarding the loss of altitude from reviewing your case and speaking to my colleagues, it looks like the cause was unfortunately a combination of factors. The first one is that you were flying in an environment with low/weak GPS signal strength, which will cause the unit to drift. While not as stable, this is where the unit relies on its sensors (vision system, barometer, IMU, etc.) to maintain balance.
This guy has very little knowledge and understanding of DJI drones.
Not having GPS means your drone does not have the ability to hold position horizontally.
But the drone can still fly and hold altitude quite normally and is quite stable in all respects except horizontal position holding..

Unfortunately though, in your case, your unit was not able to do that effectively (relatively speaking) because the unit was over water (the second factor), and the Vision Systems cannot work properly over water. When the vision system is unavailable, that is where the unit relies on the IMU and barometer.
His poor understanding is displayed here too.
The downward sensors are unable to provide horizontal position holding over water, but this has no effect on the drones's ability to hold altitude which comes from the barometer sensor which works normally whether over water or solid ground.

However, the third factor is that you took off from a boat ...
Irrelevant due to the misunderstanding of where the drone was launched.
I
s the statement about an unstable takeoff point based on that GPS-derived home point location, or is there actual telemetry or sensor data that suggests instability at takeoff? If so, I’d be very interested in reviewing that.
It is irrelevant, there was nothing "unstable" about your takeoff.
He said it because he assumed that you launched from a moving boat.

The poor GPS reception is a concern, but did not cause the problems experienced in this flight.
The issue was a lack of altitude holding and the cause of that is still a mystery.