Mavic pro forced landing dangerously, DJI avoid responsibility

[sar104]

My head is spinning. I think there is a strong language or brain barrier presenting itself here.

It is quite baffling that even after all the explanations, and after I posted the entire sequence of events from the flight, including the relevant system parameters that clearly show that the aircraft behaved correctly, in post #81, the OP is still protesting ignorance both of what happened and of why it happened. It could be a language thing, it could be sheer inability to understand the subject, or it could be clinging to the hopeless desire just to blame someone or something else. At this point it doesn't really matter. But at least the thread seems to have been of some use to others.

 

[paulmike3]

Thanks. This was my first time too. It never happen even I flew 12-15% several times before. That's why I am so frustrated because it happened to me so unprepared.

Because you were much closer and much lower on those flights, so the AC knew it didn't need to auto land yet to make it back safely. You could fly down to 1% or lower if you're at the home point, 1 foot off the ground.

I'm still totally trust DJI can make it back at 20%. Not force landing.

See, you cannot say that. As you found out, 20% was only enough battery to make it part of the way down from the 1,100 foot altitude you were flying at. You need to stop thinking in terms of percentages left, and trust that when the AC initiates it's automatic safety procedures, IT KNOWS WHAT IT'S DOING AND LEAVE IT ALONE if you ever want to see it again.

If you were higher up, it could have initiated auto land at 25% or more. The percentages are irrelevant when it comes to the built in safety features, and you're still stuck on the numbers.

Listen, it sucks that you lost your Mavic. Everyone here agrees on that. But we've proven you were at fault by overriding the built in measures meant to prevent literally the exact situation you ended up in.

 

[microlinux]

Don't feed the troll.

 

[Qoncussion]

Don't feed the troll.

Ok... That made me giggle.

 

[Missmydjimavicpro]

I'm well feed. By the way thanks everyone for the patience. One day I would do the experiment by flying at the same height and same distance and make it back home at 20% battery. I doubt DJI dare to do that even I request so because their calculations are wrong wrong. I am studying science unless you prove by real scenario. Don't tell me theory I don't really trust that.

 

[Qoncussion]

This feels like a bad mushroom trip...

 

[ac0j]

LOL! Informative, Funny, Unbelievable......
This thread delivers!
Maybe if OP keeps holding his ground, DJI will give him replacement Mavics every time his scientific experiments dont pan out. (I wouldnt hold my breath)

 

[kakao]

Looks like peyote with ''use by'' date expired a long ago ..

 

[Kilrah]

I am studying science unless you prove by real scenario.

The real scenario was your flight - and you ignore its teachings.

You're not going to last long as a scientist with that approach...

 

[Missmydjimavicpro]

LOL! Informative, Funny, Unbelievable......
This thread delivers!
Maybe if OP keeps holding his ground, DJI will give him replacement Mavics every time his scientific experiments dont pan out. (I wouldnt hold my breath)

Unfortunately they are pretty persistent as well. Will keep you up to date...

 

[Missmydjimavicpro]

The real scenario was your flight - and you ignore its teachings.

You're not going to last long as a scientist with that approach...

The theory always fail me. My colleagues always gave me a lot theory and I always prove them wrong with experiment. That's why I'm pretty stubborn and persist on my own theory.

 

[pixl]

I guess you should call this theory

My "Theory of how all design parameters are too conservative and therefore meaningless, and should therefore be ignored".

I'm just happy you're not a commercial aviation pilot -- I'd never fly anywhere.

 

[Missmydjimavicpro]

I guess you should call this theory

My "Theory of how all design parameters are too conservative and therefore meaningless, and should therefore be ignored".

I'm just happy you're not a commercial aviation pilot -- I'd never fly anywhere.

Ya, I think so too...

 

[Mad Mavic]

Enough ignorant speculation. Low battery and critical low battery were set to default (20% and 10%) but they did not control this event because smart RTH was enabled. The sequence is shown in the figure below:

View attachment 32557

At 760 s the battery % fell to the calculated smart power RTH value (32% at that distance and altitude) and the FC initiated RTH. 11 seconds later you decided to ignore that and cancelled RTH. At 915 seconds the battery % fell to the calculated smart power autoland value (20% at that altitude) and the FC initiated autoland. That's there to prevent your aircraft from falling out of the sky due to your incompetent piloting, so quit whining about it.

Morning sar104, nicely done. A thrust right to the heart, nicely done. Not to change the subject, but i'm impressed with the data you posted, especially the graph, therefore curious what software or app you used to abstract and display it. I recently began using Airdata, UAV, but can't find anything nearly as descriptive.

 

[Kilrah]

Don't know what he used for that, but you can use CsvView.

 

[Mad Mavic]

Don't know what he used for that, but you can use CsvView.

thanks Kirah, I looked at that option but I'm more interested in something that will generate the graph on its own. Especially one that adds flags at key points. Perhaps something like extracted black box data. Whatever it it, its descriptive right down to the second.

 

[BrAinZ]

Yep, when Smart RTH is enabled the alarms are the "target" and not the "trigger", i.e. instead of starting RTH when hitting low alarm it starts RTH in order to be on ground at the low alarm level. Same for Landing and critical level.

You see... that is useful info that I’m sure s lot of people didn’t quite understand (including me!)

 

[TriptyX]

this is priceless.but my bet would be on the batteries being in much cooler ambient then on ground.alarms kicked in,you cancelled,cold batteries did not deliver.5% off due to temperature and bye bye.and for all those reasons ill land at 40% and carry 3 batteries with me

 

[sar104]

Morning sar104, nicely done. A thrust right to the heart, nicely done. Not to change the subject, but i'm impressed with the data you posted, especially the graph, therefore curious what software or app you used to abstract and display it. I recently began using Airdata, UAV, but can't find anything nearly as descriptive.

Thanks - I thought that it was quite definitive and conclusive but, as you probably noticed, the OP completely ignored it.

Those data were taken from the .txt flight log posted in #27, and converted using TXTlogToCSVtool.exe. That conversion includes far more data than available from either PhantomHelp or AirData .csv conversions. The data were then imported into a data analysis program (Wavemetrics Igor Pro) which is what I use to process and visualize the telemetry. I added the annotations and pointers manually, which is very simple using Igor Pro's annotation tools. The whole process is very fast once you are familiar with the data file structure and know what you are looking for.

I'm in the process of writing a short guide on .txt and .DAT data analysis since a few users here and on PP have expressed interest. It's turning out not so short but I hope to have it in a useful form fairly soon.

 

[Eddington]

Well, even if the OP seems to not want to learn from this, others have, including me. I have only ever got my drone below 20%, and that was to test things out, and it worked perfectly. AND it was pretty much right above me at 50', maybe 30' away. I have gotten close to the 20% before but was already on the way home. From now on I plan to be on the ground at 20%.

OP, there's lots of great advice and insight in this thread, you should really take the opportunity to learn from it instead of arguing against it.

Thank you however for your actions that prompted this thread, some of us have learned a lot from it.