Obstacle Avoidance Malfunction-Lost Mavic

[Gerald Ellis]

Before I post what happened I NOW KNOW what I "COULDA, SHOULDA, WOULDA" have done in this situation but we all learn from experience and I learned an $800 lesson by losing the Mavic and someone stealing it. I am only posting this to help some of the newbies that lurk around here and maybe some of the oldies that trust the obstacle avoidance feature in the Mavic.

Here are the URLs on the Airdata site you can view to get an idea of the flight.

First part of flight
Second part of flight

I was flying a Litchi app mission that I had flown a number of times with the P3A and decided to fly the same mission with the Mavic not long after I got it to compare the video with the P3A. I have been flying RC since 1975 and started with Phantom line and every model after that until I got the Mavic. I only had the Mavic for 3 weeks when this happened.

I first noticed some loss of video on the Mavic once it was approaching the farthest point from home but it did that with the P3A so I wasn't too concerned. At the farthest point Litchi decided to crash on my Nvidia Shield tablet and that's why on the Airdata it shows as two different flights.

About halfway back and after restarting Litchi it kept pausing and gaining altitude due to a perceived obstacle. Since this is a rural area and the tallest tree I have found was around 106', I was flying much higher than that and I couldn't figure out why it was gaining so much altitude and eating up the battery with this constant pausing and altitude gains. Finally it was way past the 121 meters that I had set in the settings as maximum altitude. Getting concerned I finally hit RTH and it seemed to start moving again but then pausing and climbing again, and again, and again until it reached 981.6 ft.

Now I was really concerned and this is where I made the major mistake of waiting too long before turning off the RTH by flicking the sport mode switch to sports mode. But I knew that the RTH speed was the most economical on the battery which was now at the 20% warning level I had set. As it neared home the critical battery level was reached (10%). After turning off the RTH I was able to lower the altitude with some intermittent rising still happening.

Finally the dreaded auto landing kicked it and it started descending and I was trying to find a clear spot among the pine trees but the video was getting weak and I was panicking. Of all places to land it decided to land on top of a large barn like structure owned by the grumpiest guy who lives around here and had told me one day that he didn't like me flying over and spying on him with my camera drone. At that time I explained I wasn't spying on him and rarely if ever even flew over his 3 acres preferring to stay over unoccupied land and also explained the camera could barely make out a human at the 300' I normally flew around the 'hood and he seemed somewhat satisfied.

But when my son-in-law went there to ask permission to put a ladder up and retrieve the Mavic he was all cheerful and even offered his own ladder to look on the roof. But...alas...the Mavic was nowhere in sight on the roof nor all around that area. The Mavic didn't "crash," it landed and then shut off the motors which is when I lost data and video. The last thing I saw was the white roof of the barn. My S-I-L said if it landed on that roof that it most likely slid off and hit the ground because the roof has an extreme pitch to it.

I believe this AXXHOLE stole my Mavic but there is nothing I can do about it because I have no proof other than the data files on the tablet. I thought maybe the sheriff's office could just send a deputy out and ask him nicely if he's seen it and explaining that it was more than a toy, expensive and has data and video showing where it landed on his property but they wouldn't do that and suggested that I "talk to him" or sue him in small claims court.

Here's what I think happened to this 3 week old Mavic. It was late afternoon around 4PM and it was returning into the sun. I believe that there was some kind of reflection on the front obstacle avoidance sensors which made it "think" it was seeing something that wasn't there so it just kept rising to try and avoid this phantom object. On two prior occasions during manual flights it had stopped suddenly without the visual warning but pointed the same way into the afternoon sun but I didn't pay much attention as I was just flying around my property in different directions during acclimation flights..

All I had to do was turn off the RTH, yaw the Mavic in a different angle and I could have flown it back to the home point. But...and that's a big BUTT...Being a newbie with this OA system and with my advancing senility I just panicked and was hoping it could make it back to the home point. By the time I did turn off the RTH I was already running on low fuel tanks and only managed to bring it lower and move it a little laterally before it plunked down and landed.

So be aware...All this automation is great but it does have limitations and can fail you at the wrong time. Pausing Mavic to give you more time to ponder on the situation and/or putting it in Sports Mode can save you having a very bad experience.

I did buy another Mavic which took forever to get here but no matter what time in the afternoon and how hard I try I cannot get the new one to do what the old one did. The sun just doesn't seem to bother this one. The only difference is I did get one of those aftermarket open black shields that goes over the gimbal. But I'm not sure that has anything to do with the OA system as they use different sensors than the gimbaled camera.

 

[Cyberpower678]

Before I post what happened I NOW KNOW what I "COULDA, SHOULDA, WOULDA" have done in this situation but we all learn from experience and I learned an $800 lesson by losing the Mavic and someone stealing it. I am only posting this to help some of the newbies that lurk around here and maybe some of the oldies that trust the obstacle avoidance feature in the Mavic.

Here are the URLs on the Airdata site you can view to get an idea of the flight.

First part of flight
Second part of flight

I was flying a Litchi app mission that I had flown a number of times with the P3A and decided to fly the same mission with the Mavic not long after I got it to compare the video with the P3A. I have been flying RC since 1975 and started with Phantom line and every model after that until I got the Mavic. I only had the Mavic for 3 weeks when this happened.

I first noticed some loss of video on the Mavic once it was approaching the farthest point from home but it did that with the P3A so I wasn't too concerned. At the farthest point Litchi decided to crash on my Nvidia Shield tablet and that's why on the Airdata it shows as two different flights.

About halfway back and after restarting Litchi it kept pausing and gaining altitude due to a perceived obstacle. Since this is a rural area and the tallest tree I have found was around 106', I was flying much higher than that and I couldn't figure out why it was gaining so much altitude and eating up the battery with this constant pausing and altitude gains. Finally it was way past the 121 meters that I had set in the settings as maximum altitude. Getting concerned I finally hit RTH and it seemed to start moving again but then pausing and climbing again, and again, and again until it reached 981.6 ft.

Now I was really concerned and this is where I made the major mistake of waiting too long before turning off the RTH by flicking the sport mode switch to sports mode. But I knew that the RTH speed was the most economical on the battery which was now at the 20% warning level I had set. As it neared home the critical battery level was reached (10%). After turning off the RTH I was able to lower the altitude with some intermittent rising still happening.

Finally the dreaded auto landing kicked it and it started descending and I was trying to find a clear spot among the pine trees but the video was getting weak and I was panicking. Of all places to land it decided to land on top of a large barn like structure owned by the grumpiest guy who lives around here and had told me one day that he didn't like me flying over and spying on him with my camera drone. At that time I explained I wasn't spying on him and rarely if ever even flew over his 3 acres preferring to stay over unoccupied land and also explained the camera could barely make out a human at the 300' I normally flew around the 'hood and he seemed somewhat satisfied.

But when my son-in-law went there to ask permission to put a ladder up and retrieve the Mavic he was all cheerful and even offered his own ladder to look on the roof. But...alas...the Mavic was nowhere in sight on the roof nor all around that area. The Mavic didn't "crash," it landed and then shut off the motors which is when I lost data and video. The last thing I saw was the white roof of the barn. My S-I-L said if it landed on that roof that it most likely slid off and hit the ground because the roof has an extreme pitch to it.

I believe this AXXHOLE stole my Mavic but there is nothing I can do about it because I have no proof other than the data files on the tablet. I thought maybe the sheriff's office could just send a deputy out and ask him nicely if he's seen it and explaining that it was more than a toy, expensive and has data and video showing where it landed on his property but they wouldn't do that and suggested that I "talk to him" or sue him in small claims court.

Here's what I think happened to this 3 week old Mavic. It was late afternoon around 4PM and it was returning into the sun. I believe that there was some kind of reflection on the front obstacle avoidance sensors which made it "think" it was seeing something that wasn't there so it just kept rising to try and avoid this phantom object. On two prior occasions during manual flights it had stopped suddenly without the visual warning but pointed the same way into the afternoon sun but I didn't pay much attention as I was just flying around my property in different directions during acclimation flights..

All I had to do was turn off the RTH, yaw the Mavic in a different angle and I could have flown it back to the home point. But...and that's a big BUTT...Being a newbie with this OA system and with my advancing senility I just panicked and was hoping it could make it back to the home point. By the time I did turn off the RTH I was already running on low fuel tanks and only managed to bring it lower and move it a little laterally before it plunked down and landed.

So be aware...All this automation is great but it does have limitations and is can fail you at the wrong time. Pausing Mavic to give you more time to pondering the situation and/or putting it in Sports Mode can save you having a very bad experience.

I did buy another Mavic which took forever to get here but no matter what time in the afternoon and how hard I try I cannot get the new one to do what the old one did. The sun just doesn't seem to bother this one. The only difference is I did get one of those aftermarket open black shields that goes over the gimbal. But I'm not sure that has anything to do with the OA system as they use different sensors than the gimbaled camera.

Thank you for sharing. It does seem like the newer models aren't phased by the sun as much as the older ones are. The sun was a real killer in OA. Mine never reacted like that in the sun though.

 

[Egika]

Sorry to hear you lost that thing.
The obstacle avoidance being triggered by the sun is a well known and often reported issue.
If you are flying above any possible obstacle anyway, it would be safer to just switch it off.

 

[X424]

Thanks for the post and sorry you had to go through that experience. My Mavic is a mid November 2016 build and its OA reacts badly to flying towards the sun too. As you say, sports mode is the answer.

 

[naeemr86]

Sorry for your Mavic loss like you said that guy is an AXXHOLE. but I would recommend getting personal article policy with well known insurance company. Safe flying[emoji111]️

 

[Gerald Ellis]

Sorry for your Mavic loss like you said that guy is an AXXHOLE. but I would recommend getting personal article policy with well known insurance company. Safe flying[emoji111]️

I thought about that but I did and do have the DJI replacement policy but so far I haven't called DJI to see if they would replace it. Since it actually landed and didn't crash I doubt they will replace it and I don't look forward to spending hours on the phone trying to convince them #1 that it was stolen so I can't send it back, and #2 that it truly was a manufacturing defect in the OA system.

Since the new one doesn't seem to be affected at all by the sun it seems to me that it truly was a mfg. defect and also there was no warning I found and read about flying in the direction of the rising or setting sun.

As far as my unneighborly neighbor goes I am now intentionally aggravating him by flying Litchi orbit missions around (not over) his property using all three of the batteries I have. I'm hoping he'll try to shoot it down and then according to the Sheriff he will go to jail. Plus if it doesn't fall in the now filled lake (Google Earth images are years old, back during a drought) the DJI insurance program will replace it if he manages to hit it with gun fire. Like most people around here he owns an arsenal of firearms so could possibly bring it down.

Another odd thing about all this is that he is the president of the HOA and I am one of the board members so as I tell and retell my interactions with him with other property owners they may have second thoughts about his fake used car salesman grin and interactions.

 

[Gerald Ellis]

Thank you for sharing. It does seem like the newer models aren't phased by the sun as much as the older ones are. The sun was a real killer in OA. Mine never reacted like that in the sun though.

I think you're right. I did another "fly into the sun test" yesterday at many different angles and at different times over 3 batteries and I could not get any OA problem to happen no matter how hard I tried.