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Mavic 2 Lost to the Ages

The silver ones came with it and two of them cracked fairly quickly. So I bought some new ones and that's what I got. They seem to work fine. Should they all be replaced in full sets?

The props for the original Mavic Pro were available in either gold or silver, with the color being the only difference. But I believe the props for the Mavic 2 are only available in silver. Someone correct me if I'm wrong. But if that's the case, no, I wouldn't mix props from two different models of drone.
 
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Dude I want to take a class from you, I always see you on here interperating the flight logs down so we can understand them. Knowledge is one thing but thats a gift. Im sure a lot of people would be interested in an intrudictory class. Just sayn

Thanks. I am still writing a guide on the subject, but very slowly. Unfortunately, any detailed attempt to analyze the logs requires software and mathematical techniques that most users will not have.

The good news is that with the trajectory by
Sar104 and

sar104

Your professionalism and willingness to give of your time and knowledge is greatly to your credit and the results can be readily seen above, that aircraft would not have been recovered without your expertise. You deserve the recognition you receive from within the community.

While I quickly accept and recognise the validity of your comments regarding the mathematical level and and software requirements to perform the calculations that need to be done I'd like to gently encourage you to continue working on your guide. There are those of us such as myself who are willing to wade through the math and pay the software fees, I for one have already studied many many hours and spent many thousands on software licences and training in pursuit of the hobby/profession. I'm also sure that even with the know how and resources at your finger tips a heap of experience will be a large component as well.

It's greatly re assuring to know that we have you here within the online community to help out in these situations and as far as I can see the only limit to that is there is only one of you! Until we can submit you for cloning and have you educate your doppelgangers some of the rest of us are going to have to step up and try to get our head around the subject.

However long it ends up taking please let us all know when you have your guide completed ( so we can pester you with even MORE questions I'm sure lol)

Kudos to you!

Ari
 
Decado, Well written, I agree.
sar104

Your professionalism and willingness to give of your time and knowledge is greatly to your credit and the results can be readily seen above, that aircraft would not have been recovered without your expertise. You deserve the recognition you receive from within the community.

While I quickly accept and recognise the validity of your comments regarding the mathematical level and and software requirements to perform the calculations that need to be done I'd like to gently encourage you to continue working on your guide. There are those of us such as myself who are willing to wade through the math and pay the software fees, I for one have already studied many many hours and spent many thousands on software licences and training in pursuit of the hobby/profession. I'm also sure that even with the know how and resources at your finger tips a heap of experience will be a large component as well.

It's greatly re assuring to know that we have you here within the online community to help out in these situations and as far as I can see the only limit to that is there is only one of you! Until we can submit you for cloning and have you educate your doppelgangers some of the rest of us are going to have to step up and try to get our head around the subject.

However long it ends up taking please let us all know when you have your guide completed ( so we can pester you with even MORE questions I'm sure lol)

Kudos to you!

Ari
 
sar104

Your professionalism and willingness to give of your time and knowledge is greatly to your credit and the results can be readily seen above, that aircraft would not have been recovered without your expertise. You deserve the recognition you receive from within the community.

While I quickly accept and recognise the validity of your comments regarding the mathematical level and and software requirements to perform the calculations that need to be done I'd like to gently encourage you to continue working on your guide. There are those of us such as myself who are willing to wade through the math and pay the software fees, I for one have already studied many many hours and spent many thousands on software licences and training in pursuit of the hobby/profession. I'm also sure that even with the know how and resources at your finger tips a heap of experience will be a large component as well.

It's greatly re assuring to know that we have you here within the online community to help out in these situations and as far as I can see the only limit to that is there is only one of you! Until we can submit you for cloning and have you educate your doppelgangers some of the rest of us are going to have to step up and try to get our head around the subject.

However long it ends up taking please let us all know when you have your guide completed ( so we can pester you with even MORE questions I'm sure lol)

Kudos to you!

Ari

Thanks for the kind words, although I think that you somewhat overestimate my skills and the complexity of the problem. It's not rocket surgery, as I heard someone on a chairlift say today, but it does require some non-trivial techniques and software. I didn't mean to imply that a guide might not be useful - I was really just trying to make the point that there is no magic recipe to draw detailed conclusions from most flight logs, especially when they describe unusual events.
 
The props for the original Mavic Pro were available in either gold or silver, with the color being the only difference. But I believe the props for the Mavic 2 are only available in silver. Someone correct me if I'm wrong. But if that's the case, no, I wouldn't mix props from two different models of drone.
You’re correct sar,

The gold props are smaller than the Mavic 2 Pro props, both are low noise props but gold tip props are smaller.

Hopefully that wasn’t the problem causing the crash?

Paul
 
sar104

Your professionalism and willingness to give of your time and knowledge is greatly to your credit and the results can be readily seen above, that aircraft would not have been recovered without your expertise. You deserve the recognition you receive from within the community.

While I quickly accept and recognise the validity of your comments regarding the mathematical level and and software requirements to perform the calculations that need to be done I'd like to gently encourage you to continue working on your guide. There are those of us such as myself who are willing to wade through the math and pay the software fees, I for one have already studied many many hours and spent many thousands on software licences and training in pursuit of the hobby/profession. I'm also sure that even with the know how and resources at your finger tips a heap of experience will be a large component as well.

It's greatly re assuring to know that we have you here within the online community to help out in these situations and as far as I can see the only limit to that is there is only one of you! Until we can submit you for cloning and have you educate your doppelgangers some of the rest of us are going to have to step up and try to get our head around the subject.

However long it ends up taking please let us all know when you have your guide completed ( so we can pester you with even MORE questions I'm sure lol)

Kudos to you!

Ari
You might want to check out
Flight Controller Data Analysis - DJI
It's pretty good. But, it doesn't address the difficulties that @sar104 referred to in this post
Thanks for the kind words, although I think that you somewhat overestimate my skills and the complexity of the problem. It's not rocket surgery, as I heard someone on a chairlift say today, but it does require some non-trivial techniques and software. I didn't mean to imply that a guide might not be useful - I was really just trying to make the point that there is no magic recipe to draw detailed conclusions from most flight logs, especially when they describe unusual events.
My own take is that incident analysis is mostly about a mental picture of the drone systems, how they work, what the data should look like, and what it means if the data is anomalous. IMHO a good way, perhaps the only way, to become proficient at this is to look in depth at a few incident analyses presented in this forum.
 
Thanks for the kind words, although I think that you somewhat overestimate my skills and the complexity of the problem. It's not rocket surgery, as I heard someone on a chairlift say today, but it does require some non-trivial techniques and software. I didn't mean to imply that a guide might not be useful - I was really just trying to make the point that there is no magic recipe to draw detailed conclusions from most flight logs, especially when they describe unusual events.
there is a little bit of the documentation on this topic here, but, it is dificult to say how much of it can really apply to dji set of available metrics.
ArduPilot/MissionPlanner

specific section for that is in the 'dataflash logs' section of the interface, 'review a log'. that opens up a window with some pre-configured log graphs - mosy useful ones are vibration 3.3 review, velocity vs innovation, errors, etc.
1552917968886.png
 
Thanks for the kind words, although I think that you somewhat overestimate my skills and the complexity of the problem.

Hi Again

My appreciation of the contribution you give goes beyond your skill set or your ability to address the problems complexity. That said, I am not the "bluntest knife in the draw" and yet *I* am not able to provide the level of expertise in the field that you are at this point, or any level of expertise for that matter so I think you sell yourself a little short. Perhaps this can be attributed to your exposure to the problem and experience in dealing with the variables but that is outside of my viewpoint in this thread.

Regardless of the level of expertise required and how it was obtained currently in these forums you appear to be the most practiced at it and most importantly you are willing to offer your time and that expertise on a volunteer basis. I've had more than a couple of technical pass times over the years not even touching on professions, I've been a volunteer in all of them at one time or another at one level or another. I've also managed an online community somewhat larger than these for 14 years with it's various forums and users submitting captured data for analysis and all the other facets.

That makes me well aware of the value of people who step up and offer their services, you can never find enough of them and community demands and the tendency to take them for granted over time often lead them to burn out in the end, I did on more than one occasion. You fall into this category of "people who step up" and that is what is truly golden.

I do realise I may make you a little uncomfortable highlighting your input and for that I apologise, but I think it is a good thing to underscore to the community from time to time that which all of the "people who step up" bring with them and contribute and that it is not without personal cost.

You might want to check out
Flight Controller Data Analysis - DJI
It's pretty good. But, it doesn't address the difficulties that @sar104 referred to in this post

Thankyou BudWalker

Another worthwhile contribution, I may well of got there by myself in the end but now that's time I do not need to expend finding it and can now use evaluating it instead.... "people who step up"

My own take is that incident analysis is mostly about a mental picture of the drone systems, how they work

That as a certified commercial RePL I have, I'm sure many others do also.

what the data should look like, and what it means if the data is anomalous.

That as yet is a sense I have not had time to acquire to the degree needed.

IMHO a good way, perhaps the only way, to become proficient at this is to look in depth at a few incident analyses presented in this forum.

Total agreement with the addendum that one should always take any shortcut opportunity to learn from those who have already done so. We all have a life, family and other interests and responsibilities that make it desirable to minimise "time investment" to reach a goal.

but, it is dificult to say how much of it can really apply to dji set of available metrics.

That's one thing we need to ascertain.

specific section for that is in the 'dataflash logs' section of the interface, 'review a log'. that opens up a window with some pre-configured log graphs - mosy useful ones are vibration 3.3 review, velocity vs innovation, errors, etc.

Thankyou now paulatkin73. Every "heads up" along the way reduces the learning curve and research effort for the rest of us, once again "people who step" up no matter to what degree.

Perhaps I put too much emphasis on the technical know how and abilities required, although to be honest I don't think so. My main intention probably due to my past activities in online communities as mentioned above was to highlight the value of a "people who step up" and the opportunity for the rest of us to benefit even more from them when they are willing to freely share of their particular skill set. When you see someone say "I have been writing a guide" if you are wise you encourage steps for the benefit of all.

Since my previous post in this thread I have picked up the run times for MATLAB and spent a night over at a friends place who through working in rather esoteric and somewhat classified areas of drone applications is far more across the subject than I am. Over the obligatory Australian mateship ritual of "having a few beers" he has run me through "drift mapping 101" and that brings me full circle.

sar104 has taken the time out to develop a skill set that I admire and would like to at least try to acquire myself and I'm sure I'm not the only one. I'm likewise sure many of us could arrive at that point ourselves and get it "one piece at a time" as the man in black said but I'll take any push along towards the right direction I can get from those who have already made the journey.

It's been my experience that it will only be once you become proficient with the tools and techniques required for the job that you can then as BudWalker rightly suggests "look in depth at a few incident analyses presented in this forum" with full appreciation.

sar104, it's fully accepted that there is "no magic recipe to draw detailed conclusions from most flight logs, especially when they describe unusual events."as you put it. It was always going to about "Tools, Techniques and Practice/Experience". Your guide when completed and input from others like above can only help those motivated enough acquire the first two parts of that formula allowing them to build the last as they must by themselves. It'll be no different for me.

Once again, sorry for any discomfort engendered sar104, I did want to "shine the spotlight" a little, "Render unto Ceaser" as they say. I also apologise for the thread hijack, I do that sometimes sadly, probably a byproduct of overthinking. I do admit to a veiled attempt to encourage others to follow your example.

Perhaps at some time a subsection in the forums devoted to log and data analysis might be desirable. The owners/chief moderators will have to look at that.

Perhaps I should stop meddling, in this community I'm no one in particular (and quite happy to be that lol). I just can't abide with letting something that should be said left unsaid I suppose.

I'll shut up now.

Regards
Ari
 
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Probably it is a dumb question, but should not it RTH when the RC signal is lost?
 
Probably it is a dumb question, but should not it RTH when the RC signal is lost?
The drone is programmed to RTH on loss of signal.
But all the programming in the world isn't much help if you fly 6 miles out and there isn't enough battery for the return trip.
 
The drone is programmed to RTH on loss of signal.
But all the programming in the world isn't much help if you fly 6 miles out and there isn't enough battery for the return trip.

That didn't answer the question at all that KEM asked.

The battery had NOTHING to do with the crash. As you can see there was still about 50% left and I had already returned back 2000 feet from it's furthest point. My calculations show I still would have made it back with 5% battery. And if not, It was no problem for me as I know pretty much everyone along that route and when the battery was too low, if it didn't make it back, then I would just land at one of their houses.
The problem was not the battery. I should have had a strict line of sight on the drone, and I did not. Drones do have problems and they do lose signal and can even if you are close, which is a good reason to make sure that you do not fly over people.

@ Kem - RTH should make it come back and that is the right setting most of the time. It makes sense that when the drone loses it's connection it needs to go somewhere.
My analysis of the flight data looks like the motors overloaded (it showed that error on the screen) and the drone shutdown for safety reasons when the speed was to great.
 
The battery had NOTHING to do with the crash. As you can see there was still about 50% left and I had already returned back 2000 feet from it's furthest point. My calculations show I still would have made it back with 5% battery.
The drone was 9.5 km out and the battery was at 44%.
Sure ... you could have taken the long way home.
No worries at all.

The way the battery was going, you had enough power for 6 kilometres tops.
 
12 minutes from the homepoint would put it at 27 minutes total. That's close, but should still make it based on past flights.
 
12 minutes from the homepoint would put it at 27 minutes total. That's close, but should still make it based on past flights.

There was a headwind coming back, as I mentioned earlier. It wasn't going to make it based on the battery depletion rate. It's a moot point anyway.
 
It’s a sad, sad day when you lose your drone. You leave the 99 to go after the one that’s lost and when you cannot find it you grieve.

In anticipation of spring I decided to fly tonight because it was so calm out. The sun was nice this evening and it was all good. The drone flew high and the drone flew low and flew graciously for miles. It could almost imagine the spring sun warming my face as I looked up into the sky!

Oh, but then tragedy struck. The dark clouds flew over and it began to rain on my drone parade (figuratively, of course) as I flew nearing a couple of rows of high tension power lines. The drone started going crazy!

Immediately, the drone started twisting (horizon distinctly tilted) to one side and came up in the DJI Go4 app that there was too much attitude. I’m sure it must have been writhing in pain, as it looked to me. It gave an error that there was too much wind. Funny, because it was completely calm even up higher as we have windmills that start turning at 6-7 mph. Then it gave an error the motor was beyond maximum speed. I told it to "Return to Home".

After that the screen said it was losing signal and everything went black (blank).

I’m sure it was crying out in pain as I wasn’t there to comfort it. I directly went to where the picture showed last on the screen. I got the coordinates and put them in my phone along with the DJI Go4 app and went right to it but it wasn't there. I scoured the cornfield where it said it had fallen, as much as possible I could, looked for the body lying cold and dead. I went back and forth, going up and down the rows in a large area but it was not to be found.

Visually I did not see it fall or fly as I had a some fields and trees in between. What I do know is it’s a sad day. :(

Oh man. So sorry to hear that. Are you going to replace it?
 
Oh man. So sorry to hear that. Are you going to replace it?
It was found. With the help of SAR and the website that turns your log into a path. I searched the area and found it about 270' due east of the last point of contact.
It is being replaced right now. I've contacted DJI and they are sending a replacement.
 
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I should have had a strict line of sight on the drone, and I did not. Drones do have problems and they do lose signal and can even if you are close, which is a good reason to make sure that you do not fly over people.

overall it is true, but, it is not that simple. there are plenty of models that are flown way away from the line of sight. most planes fly way away from where you can see them, still they have an ability to return.
each software has a certain level of confidence of what is expected to happen in a case of a certain malfunction. there should be various levels of reactions to emergencies, and, what is bothering me the most now with those DJI models and software they made - it seems like in the scenario of a multiple IMU errors where factual gps/compass reading starts to deviate from the IMU and recognized movement deviates from the innovation dictated by the flight controller - in this scenario ideally model needs to land immediately.
DJI model seems to be switching into some limbo mode instead and drift away with the wind - perhaps because engineers anticipated user to follow regulations and maintain line of sight, perhaps, but, it seems that any DJI operator needs to keep this in mind that those models are not truly capable to self-navigate and support multiple layers of reactions to different emergencies. i hope i will never have to experience an IMU fault on mine, but, it is apparently not impossible, and, it is quite odd. also, it is a pity DJI set only a single compass on this model. anything worth more than $500 of gear should have at least double redundancy of critical systems and it is beyond comprehension why they decided to save 5g of weight and not use a double gps/compass unit. it is just not smart at all.
 
overall it is true, but, it is not that simple. there are plenty of models that are flown way away from the line of sight. most planes fly way away from where you can see them, still they have an ability to return.
each software has a certain level of confidence of what is expected to happen in a case of a certain malfunction. there should be various levels of reactions to emergencies, and, what is bothering me the most now with those DJI models and software they made - it seems like in the scenario of a multiple IMU errors where factual gps/compass reading starts to deviate from the IMU and recognized movement deviates from the innovation dictated by the flight controller - in this scenario ideally model needs to land immediately.
DJI model seems to be switching into some limbo mode instead and drift away with the wind - perhaps because engineers anticipated user to follow regulations and maintain line of sight, perhaps, but, it seems that any DJI operator needs to keep this in mind that those models are not truly capable to self-navigate and support multiple layers of reactions to different emergencies. i hope i will never have to experience an IMU fault on mine, but, it is apparently not impossible, and, it is quite odd. also, it is a pity DJI set only a single compass on this model. anything worth more than $500 of gear should have at least double redundancy of critical systems and it is beyond comprehension why they decided to save 5g of weight and not use a double gps/compass unit. it is just not smart at all.
Back in the good old days (before the Mavic series) the P3's flight controller would do something like what you're suggesting. Specifically, it would detect a difference in heading computed from the magnetometers and the heading the FC computes from the IMU data, and also, at a lower gain, the magnetometer data. AKA a Yaw/magYaw separation.The FC would respond by switching to ATTI mode and the pilot then had to provide navigation. But, the problem was that this lead to false positives. Each FW revision would attempt to be better at detecting valid Yaw/magYaw separations but at the expense of increasing the false positive rate.

The Mavic Pro used a different strategy. Instead of switching to ATTI it would attempt to reconcile the Yaw/magYaw separation. When a Yaw/magYaw was detected the FC would rotate the AC while holding the computed Yaw constant. The rotation would then stop when the Yaw agreed with the magYaw. Sometimes this works, and sometimes it doesn't. This post was the first time I saw this.
Recorded flight data vs real time data

Now, it seems that all the DJI platforms use this strategy including the P3.
 
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Back in the good old days (before the Mavic series) the P3's flight controller would do something like what you're suggesting. Specifically, it would detect a difference in heading computed from the magnetometers and the heading the FC computes from the IMU data, and also, at a lower gain, the magnetometer data. AKA a Yaw/magYaw separation.The FC would respond by switching to ATTI mode and the pilot then had to provide navigation. But, the problem was that this lead to false positives. Each FW revision would attempt to be better at detecting valid Yaw/magYaw separations but at the expense of increasing the false positive rate.

The Mavic Pro used a different strategy. Instead of switching to ATTI it would attempt to reconcile the Yaw/magYaw separation. When a Yaw/magYaw was detected the FC would rotate the AC while holding the computed Yaw constant. The rotation would then stop when the Yaw agreed with the magYaw. Sometimes this works, and sometimes it doesn't

that makes sense.
the part that baffles me, still, is the fact that DJI left the final failsafe not exposed into the settings anywhere and this final 'ATTI mode switch' is indeed used instead of the forced landing. it is really difficult to understand, as a flyaway wil always end with an uncontrollable crash. failsafe forced landing at least prevents possible property damage on the ground.
 
that makes sense.
the part that baffles me, still, is the fact that DJI left the final failsafe not exposed into the settings anywhere and this final 'ATTI mode switch' is indeed used instead of the forced landing. it is really difficult to understand, as a flyaway wil always end with an uncontrollable crash. failsafe forced landing at least prevents possible property damage on the ground.
Actually, that's not correct. Flyaways don't always lead to a crash.
 
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