Serious bug in the Mavic's "Home Point Me" function - caused loss of drone!

[Robbyg]

I have had my mavic pro for about a month. I have read a lot about fly aways,etc and have been terrified of the same thing happening. I always calibrate my compass and IMU, set the return home point and check all my limits, never had any problems so far.

Just a word of advice. By doing a calibration of the compas and IMU before each flying session, you are actually increasing your odds of having a disaster. Once the craft is properly calibrated it will remain that way unless you either crash or occasionally it will go out of calibration after a firmware update. Other than that each time you calibrate you risk changing a good calibration with one that might not be correct.

I have had mine for 9 months and have done 3 compass calibrations and have never calibrated the IMU. She works perfectly and is often times a mile out over the ocean following boats.

Rob

 

[Lefkaditis]

Amateur hour! Read the manual. Know your equipment. This was not caused by the app nor is it DJI's fault.

Always make sure you get the ; "the home point has been updated. Please check it on the map", before every single take off.

Also check your mobile device GPS is activated if you want use return to home me.

Why didn't you just hit the pause button on your transmitter until you figured out the problem?[emoji848]

 

[BuzzyOne]

For the new folks reading this thread (and maybe some of the more experienced):

Learn how to fly back to your controller location manually by using the radar screen on the bottom left of the DJI app screen. Once you understand how it works, you will always know which way the Mavic is pointed relative to your position. All you then need to do is rotate the Mavic until it is pointing at you and apply forward throttle. Also watch your telemetry and you should see the distance number getting smaller. Practice this until it becomes familiar. Once mastered, you could RTH manually every time.

The radar screen is also helpful as it has a horizon indicator, which can indicate wind direction and velocity (which is often different at ground level).

 

[dscline]

These things are not meant to just be left to their own devices.

Which is why DJI didn't spend any time developing and marketing autonomous features, like tracking subjects on its own or flying home on it's own. Oh, wait. This is a thread about a bug in an intended feature of the drone. You've posted ten times in this thread, just to reiterate how stupid you think people are. That's an interesting way to spend your time.

 

[scjerry]

For the new folks reading this thread (and maybe some of the more experienced):

Learn how to fly back to your controller location manually by using the radar screen on the bottom left of the DJI app screen. Once you understand how it works, you will always know which way the Mavic is pointed relative to your position. All you then need to do is rotate the Mavic until it is pointing at you and apply forward throttle. Also watch your telemetry and you should see the distance number getting smaller. Practice this until it becomes familiar. Once mastered, you could RTH manually every time.

The radar screen is also helpful as it has a horizon indicator, which can indicate wind direction and velocity (which is often different at ground level).

Can the radar screen be enlarged? I find it difficult to use in bright sunlight, even with a sunshade. In the meantime, both HP reset features should be disabled until the bug is fixed, since neither HP-reset-to- current-aircraft location nor HP-reset-to-RC works reliably and disabling it might save a drone for someone who is not following this thread.

 

[dscline]

Can the radar screen be enlarged?

Just tap it. The radar screen and camera view will swap places.

 

[BuzzyOne]

Just tap it. The radar screen and camera view will swap places.

That's for the map, not sure you can do the same with the round radar screen on the left.

 

[Dale]

If your app crashes as it does sometimes on Android, can you navigate back from a distance with just the controller?
I failed to see any telemetry on the controller that would help.

 

[Robbyg]

If your app crashes as it does sometimes on Android, can you navigate back from a distance with just the controller?
I failed to see any telemetry on the controller that would help.

Well you can RTH but assuming you end up like I did and forgot to set a proper RTH height you can still do it. I had to do it from 3000ft out on my 5th flight just using the LCD on the RC.

The display shows Height and Distance and that's all you need!

First stop all other stick inputs and just gain altitude so you can clear everything on your path home. Go up to 400ft if your not sure.

Second move the drone forward for a few seconds and look at the distance value on the LCD. Is it getting larger or smaller. If it's getting larger Yaw the craft a bit and see if the distance is decreasing. Keep Yawing then moving forward for a few seconds in small amount until you get the distance dropping as fast as possible. You may have to nudge a little left and right to find the exact heading that closes the distance the fastest.

Once you got the direction locked in go full bore forward and keep watching the distance reading. When you get within 50ft you should be able to hear the drone. Just start your descent until you have a visual and then land her.

Rob

 

[finlayson]

I heard back from DJI regarding my case, and they have (in their words) "confirmed it as a warranty case according to our analysis”.

To compensate me for this, they offered me a 100% coupon code for a replacement Mavic Pro (without remote controller) that I can order from the DJI online store. (This is just for a Mavic Pro; I won’t be able to use this to upgrade to a Mavic Pro Platinum

Unfortunately, DJI’s response made no mention of the specific bug that caused this, but (because they took responsibility for it) it’s clear that they’re aware of the problem. I would not be surprised to see a new version of the “DJI GO 4” app - fixing the “Home Point Me” problem - appearing soon. But - in the meantime - DO NOT use the “Home Point Me” function!

This will be my last posting on this thread. Thank you to those people who took the time to properly read and understand my postings before responding.

 

[S. Lee]

I don't think it's the same, but similar. My Mavic for som reason had no GPS signal and right after take off, the Mavic just flew away. My RC had no control over the Mavic and looking at the flight log, elevated to 700 feet before crashing after about a 4 minute flight. I drove around looking for it and luckily I used the video replay to find the location of the crash. After 5 hours, 1 trip to Home Depot, and lots of masking tape, I was able to lodge my Mavic out of branches that was about 35-40 feet up. Amazingly, no physical damage and just the gimbal didn't work. So, crossing my fingers, I just replaced the gimbal cable even though there wasn't any visible damage to it and after 5 hours of watching YouTube videos and replacing the gimbal cable, my Mavic finally works!!! This Mavic was actually a replacement one DJI sent me in August and the gimbal wasn't actually working right out of the box, but now that's gone as well. I believe DJI sent me a Mavic that didn't have a 100% working gimbal cable which I expected since it was a replacement through DJI Refresh. I have to some research to find out what happened.

 

[sar104]

I don't think it's the same, but similar. My Mavic for som reason had no GPS signal and right after take off, the Mavic just flew away. My RC had no control over the Mavic and looking at the flight log, elevated to 700 feet before crashing after about a 4 minute flight. I drove around looking for it and luckily I used the video replay to find the location of the crash. After 5 hours, 1 trip to Home Depot, and lots of masking tape, I was able to lodge my Mavic out of branches that was about 35-40 feet up. Amazingly, no physical damage and just the gimbal didn't work. So, crossing my fingers, I just replaced the gimbal cable even though there wasn't any visible damage to it and after 5 hours of watching YouTube videos and replacing the gimbal cable, my Mavic finally works!!! This Mavic was actually a replacement one DJI sent me in August and the gimbal wasn't actually working right out of the box, but now that's gone as well. I believe DJI sent me a Mavic that didn't have a 100% working gimbal cable which I expected since it was a replacement through DJI Refresh. I have to some research to find out what happened.

Post the log file and/or DAT file if you want to know why it happened.

 

[scjerry]

Using DJI Go 4 v. 4.1.7, several of my detailed log files submitted to DJI, showed two events, the original location of the HP-to-Me request, and 3 spreadsheet-lines later, the location of HP Recorded. The former shows up on the map, the screen message and the voice message with accurate distances to the previous launch HP. The latter does not and may be miles from your RC/mobile device. It is the location of HP Recorded that is used for RTH.

DJI responded to my defect report. They want me to return my Mavic, since its under warranty. I'm hesitant only because some on this list have done so, only to have it returned with no defect found.

Before I do, I will try the new DJI Go 4 v. 4.1.10 with new features.

 

[chopcat]

A very interesting thread. Although I am not sure how the problem could occur., maybe just here.
We have to fly maintaining visual contact at all times so at the point where you want to RTH you can see the aircraft. So if it zooms off in the other direction you know about it pretty quickly and abort.
Of course if it is flying out of sight then it is a different matter.

 

[scjerry]

Yea, that's the different matter.

 

[Bolewsky]

Just to make a point.. all those people who said that it was the users fault.. were wrong. Just plain wrong. Confirmed wrong. Lefkaditis - wrong. Oingo Boingo - wrong. ZUCSTA - wrong. Dragonfly - wrong. and so on..

 

[scjerry]

Just to make a point.. all those people who said that it was the users fault.. were wrong. Just plain wrong. Confirmed wrong. Lefkaditis - wrong. Oingo Boingo - wrong. ZUCSTA - wrong. Dragonfly - wrong. and so on..

There is an implicit assumption made by well-meaning posters (usually, those with greater experience...but not always) that, by definition, a newbie is too dumb to read the manual, and is wrong in asserting that his/her problem is due to a flawed bird.

I've gleaned good advice from this list by separating the chaff from the wheat...I mean by that, listen to those who respond with reasoned logic, demonstrated knowledge and advice...and..aren't rude.

The good news is that DJI has provided users with a set of data tools. Often, these tools are augmented by a dedicated user community.

So, here's my list of things to do before posting serious problems here:

1) Identify the date and time of the problem and upload (sync) the log files to the DJI cloud through the DJI Go 4 app. Assuming you are disconnected from the AC but connected to wi-fi, on the lower left of the opening flash page, there is an upward pointing arrow above the "Disconnected" message, or press the three horizontal bars in the upper right and select Flight Record. In the upper right corner of the Flight List, press the small circular icon to obtain a sync menu, then make your choices, assuming the errant flight is recorded. You won't find the words "sync" or "Flight List" in the Mavic Pro User Manual.
2) Use HDSync.com (now AirData) to upload your log to AirData.com. You'll need to establish an account with them.
3) Download the associated Comma Separated Values (.csv) file, and open it with your favorite spreadsheet app. Across the top, peruse the column names. You may need to expand the column widths to see the data. I save these files converting them to .xlsx and discarding the .csv file.
4) Download the .txt file from AirData. I upload it to Phantom Help DJI Flight Log Viewer. Download their .csv and save it to an .xlsx file as before. Mysteriously, you will get a different spreadsheet than from AirData.
5) Deciphering .csv file column headings can be challenging, but here is one document that may help: Mavic Pro .csv Column Descriptions
6) Note that retrieving .dat files using DJI Assistant 2, stopped working with recent firmware upgrades. See DJI Support, Assistant 2 and Flight Data. With recent new releases of both the firmware and Assistant, this will be potentially a future option if/when DJI gets its act together. See How to retrieve a V3 .DAT File
7) See the post by Daroga on the role of the two log files: Dat files and txt files: Log txt vs log dat .
8) For lost drones, the columns most useful are the Home Distance, GPS coordinates of launch HP, and changes in the GPS coordinates of the HP with time. Note that Attempt to reset home point to RC/Mobile device resulted in map, voice and display messages that were reasonable, e.g., recorded home distances that matched the log entry. The Home Point Recorded, a spread sheet line in the log file, in my case, showed a home distance of 12,300 feet, more than 2 miles away, and was NOT reflected in the map, voice and display messages. Home Point Recorded is the location used by RTH. This is evidence of the bug, but I only found it using the Phantomhelp spreadsheet derived from the .txt file.
9) Make sure your mobile device GPS works and agrees with your Mavic. That should be done periodically.
10) Update with the latest Go and firmware. Note that I've rec'd two updates to DJI Go 4 in two or three days. I just installed firmware, v. 01.04.000, then I installed DJI Go 4 v. 4.1.10 two days ago, now, today, they send me DJI Go 4 v. 4.1.11. Improved flight safety, they now claim! WOW!

Hope this helps and won't be needed with recent updates.

 

[BudWalker]

........
6) Note that retrieving .dat files using DJI Assistant 2, stopped working with recent firmware upgrades. See DJI Support, Assistant 2 and Flight Data. With recent new releases of both the firmware and Assistant, this will be potentially a future option if/when DJI gets its act together. See How to retrieve a V3 .DAT File
.......

This has been fixed since DJI Assistant 2 V1.1.6. DJI certainly hasn't made it simple though. It's all explained in that link you gave.
How to retrieve a V3 .DAT File

 

[scjerry]

I've attempted to download and install DJI Assistant 2 v.1.1.6 twice, only the last attempt today was successful. The first attempt triggered a virus alert and Norton virus s/w blocked installation of a .dll . The 2nd was successful and I've yet to try it with firmware v. 01.04.000.

 

[Gerald Ellis]

I heard back from DJI regarding my case, and they have (in their words) "confirmed it as a warranty case according to our analysis”.

To compensate me for this, they offered me a 100% coupon code for a replacement Mavic Pro (without remote controller) that I can order from the DJI online store. (This is just for a Mavic Pro; I won’t be able to use this to upgrade to a Mavic Pro Platinum

Unfortunately, DJI’s response made no mention of the specific bug that caused this, but (because they took responsibility for it) it’s clear that they’re aware of the problem. I would not be surprised to see a new version of the “DJI GO 4” app - fixing the “Home Point Me” problem - appearing soon. But - in the meantime - DO NOT use the “Home Point Me” function!

This will be my last posting on this thread. Thank you to those people who took the time to properly read and understand my postings before responding.

Congratulations "finlayson" for bringing a confirmed bug to DJI's attention and getting your MP replaced. Let's hope they fix this in their next update.
I refrained from posting earlier in this thread as I didn't have anything to add after you explained exactly what happened and it appeared to me (and should have to others) that it was truly a bug in DJI's software. What amazed me was the people who posted calling it pilot error or you should have done this or that. A bug is a bug regardless and that was the point. Many of the posters didn't even understand your point that it was a bug in the "Return to Home Me" not the normal RTH thus not adding anything to the conversation. This is one of the few threads with a complete exoneration from by DJI of "pilot error" which is a big plus for this forum. Best of luck and keep 'er flyin'!