Lost Mini 2 failed RTH - Help with analysis and GPS

[LDizz]

Hi everyone,

My apologies in advance if I ask any stupid questions or haven't provided all relevant details.
I know sweet FA about flying drones, I am just trying to help my friend who lost his Mini 2 in a failed RTH with critical battery loss at 1km. (0.7mile) from home.

Attached is the flight data file from app.airdata.com. Any insight into calculating the GPS location would be greatly appreciated, I can definitely use all the help I can get with wrapping my head around this and hopefully finding the Mini in tact.

Cheers everyone.

 

[Deleted member 103366]

Your log on phantomhelp DJI Flight Log Viewer - PhantomHelp.com
Since you say that that log is from airdata could you post the link to the airdata webpage?

 

[Paint Rock Drones]

From the map, it looks like the flight ended somewhere near the intersection of Marshall St. and Batty St., in a development. But presumably you could see that yourself. What other information are you looking for?

Of course since the last log entry indicated it was still trying to RTH, it may have continued a bit further after it lost communication with the controller (anything after that would not be in the log on the phone). The last reported altitude was still 262 Ft. above the takeoff location, and the log does not indicate a forced landing had been initiated yet. So if I were looking for this drone I would draw line from that last point on the map to the home point, and look a bit on both sides of it starting at the last known position, including up in the trees.

(I'm not a log reading expert; others may be able to help further)

 

[Deleted member 103366]

BTW your it seems your friend went RIDICULOUSLY HIGH, 1640ft/500m i.e. the firmware maximum, at the start of the flight and maybe illegaly high (400ft/120m legal limit?). Two minutes of full throttle climb!!!!!!! They 'wasted' near enough 40% of the battery in the near vertical climb and descent to and from that height.


If this was a battery disconnection then the drone fell.
I would start looking in the ringed area, the RTH appears to have been flying into a headwind that was also blowing slightly to the drone's right.
At the end of the log I think the ground beneath the drone is roughly 10m, or more, below the take off point, if correct then the freefall was likely near 300ft and possibly took around 10seconds and I don't hold out much hope of the drone being intact, it looks like a hard surface crash site.
Assuming I am correct and the ground drops away from the take off point your friend would, I think, have done themselves a favour by reducing the height during the RTH, they likely had room to play with and descending would likely have dropped the drone into slower winds.

If this was a disconnection between the controller and the drone then the drone would after a short interval have continued to RTH until a critical battery landing was triggered at 10?%

How old was this drone?
The battery had only 1 charge cycle on it but I can't find an activation date for the drone in the logs.

 

[Paint Rock Drones]

@PhiliusFoggg
Given the periodic disconnects earlier in the log, isn't it more likely that the drone disconnected and kept flying after the last known position rather than a battery disconnect and fall at the last known position?

 

[Steve.bridges]

What happened mid flight were periodic disconnections due to buildings being in the way. The final disconnect was due to mobile phone dying.
Obviously i was returning home when my phone died. I was only 600m away from home, 15% battery left and 80m in the air so would have 100% made it home easily.
When the phone died I didnt touch the controller (which was still beeping as it would if drone was returning home) because I thought that because it was already on its way home it would just continue. It never turned up, and a thorough search of last recorded location have been unsuccessful.

I can usually see it coming home from about 500m away but never saw it at all.

 

[Paint Rock Drones]

The phone dying would be a critical piece of information.

Did you follow the link that @PhiliusFoggg gave you in his first reply? According to that log analysis, the drone was telling you "Strong wind warning. Aircraft unable to return to home automatically. Lower altitude immediately and return to home manually (Code: 30149)." It continued to give you that warning even after you descended.

So it seems likely that after your phone died, the drone continued to try to return home. But due to the wind, it was unable to reach you before it hit the forced landing threshold (10%?). Unfortunately you don't have access to any log information after the phone died, so you don't know how far it travelled before initiating the forced landing. Fortunately, it seems more likely that there would have been a forced landing, which is better than falling abruptly from 80 meters.

 

[Steve.bridges]

Yeah I did notice that, but that windows warning displays all the time and it still manages to get home. Without wind it's return home speed would usually be about 37kmph and it was coming home at around 30kmph so the windows wasn't impacting too much. I guess I have a straight line of about 600m to search (don't know how I'll climb all those fences and roofs along the way though haha.)

You're probably right though because usually when it force lands at 10% I have a video feed and am able to use the controller still to get home as it descends

 

[Deleted member 103366]

I was only 600m away from home, 15% battery left and 80m in the air so would have 100% made it home easily.

I doubt that is true.

Using the data from the Phantomhelp scrollable display. At disconnection the drone was 1985ft at 15% battery. Earlier, at 11min 50sec, the drone was 4005ft away and 31% battery, so 16% battery was used to travel the last 2020ft to the disconnection.
Couple that with the fact that, as the battery approaches zero a greater proportion of its available power has to be used to simply keep the drone in the air and you arrive at the conclusion that is doubtful that you could have got the drone home even if you had been able to monitor the drone.

Then add to that that once the drone reaches 10% or thereabouts it enters a force landing mode where siginificant throttle input is needed just to keep the drone in the air. I suspect you were unaware of this and likely did not take appropriate action and I suspect that your drone stopped its attempt to return home when the battery reached that threshold and landed.
Use the search function in here to look for other threads where a drone has been lost due to critical battery.

If the drone continued to use power as it had been (which I think is the most optomistic viewpoint) then it might, wind depending, have made it another 1000ft towards home which might get it to Tiki Ct but I would be surprised if it made it that far.

Given the neighbourhood if it landed in someone's property I think you might have some awkwards questions to answer about how your drone got there

 

[Steve.bridges]

Yep, as I said usually I'd have the video and be able to guide it home with the controller as its force landing. But thank you

 

[Steve.bridges]

So it looks like from 20% to 15% it flew about 200m , so would I be correct in saying it probably flew roughly another 200m before being forced to land?

 

[eEridani]

It appears to me the flight went illegally high, draining the battery much more than needed (as PF noted). Then, the pilot flew downwind over a mile, played around trying to take a pano and changing flight modes - all the while ignoring high wind warnings. Dropped altitude and futz'd around some more. Then the battery went below a safe return level of 49%, auto RTH triggered, and while trying to get back lost signal a few times and was fighting wind the entire trip. It only had power to make it part way back.

It was only making 1,000 feet per minute headway, using 10% of the battery in that same time. Log stops where the battery is at about 10%. So check from 2,000 feet out to 1,000 feet out on the RTH line. The drone probably landed in that zone.

 

[Meta4]

Yeah I did notice that, but that wind warning displays all the time and it still manages to get home. Without wind it's return home speed would usually be about 37kmph and it was coming home at around 30kmph so the wind wasn't impacting too much.

Obviously the wind was affecting your flight too much for the drone to be able to get home.
You made a classic newbie mistake of flying off downwind in conditions that ensured the drone would fight against a headwind for the return flight.
You added to the issues by burning too much battery and not attempting to come home until the battery reached 49% and then leaving it to fight a headwind, in auto RTH 100 metres up.

I guess I have a straight line of about 600m to search (don't know how I'll climb all those fences and roofs along the way though haha.)

Looking at what that search area looks like, your only hope is that you properly labelled the drone and someone returns it to you.
If you didn't label it, you didn't really want it back.

 

[Deleted member 103366]

Why did you fly so high 1640ft/500m and so far 6283ft?

Drone rules

Australia’s recreational drone rules are designed to keep you and others safe, on the ground and in the air. Here are the rules you need to know now, before you take-off.

www.casa.gov.au

To be honest the more you say about this flight the worse it becomes.

It seems
1) you imply you regularily fly beyond your visual range "I can usually see it coming home from about 500m away" which also suggests your have some experience of drone flying.
2) you flew to a grossly illegal height ( more than 4 times the legal limit?)
3) FAR beyond your own stated range of VLOS which is 500m /1640ft
4) in adverse wind conditions, Flying outbound downwind to the low battery RTH is stupid.
5) over a built up area (thereby endangering people and property)
6) with an insufficiently charged phone and therefore not even able to use the screen device as a guide to flying albeit a not legal guide.

In some respects I think it would be better if you did not find your drone

 

[eEridani]

Winds reached 28+ MPH, and averaged 20 MPH on the return flight, M on...

 

[Steve.bridges]

Jeepers came here for a bit of help... drone people are mean! Yes it's labelled so fingers crossed. But wowza, some of you sound like you'd be real fun at a party.

 

[Deleted member 103366]

No we are not mean, we, unfortunately, likely gave you the information necessary to find your drone.

Also unfortunately we get penalised with further restrictive laws because of people such as yourself who fly idiotic flights and compound that by posting them all over the internet and who then take your current attitude when you are told the flight was illegal and ill advised.

You would do yourself AND US a favour and if you took what you have been told on-board and fly sensibly and with in the law and do not spit your dummy-tit out when you get your hand slapped.

Better we slap your hand than you have your Police or CASA come knocking on your door or someone sue you for damages and or trespass caused by your drone and or your propsed actions in recovering it. aka post #9 "(don't know how I'll climb all those fences and roofs along the way though haha.)"

 

[Steve.bridges]

Alright pal I've got better things to do than argue with people online but let's just understand what's going on here. So I've had the drone for probably less than a month, so I suppose I am what you referred to as a 'noob'. In fact, this is the first drone forum I've ever engaged in. Because of that, perhaps I was somewhat ignorant of the rules which of course is my fault. But given my experience here and the berating you've so happily given out, which i can only imagine is due to the need to make yourself feel big and superior, I don't think I'll be returning any time soon. That being the case I'm sure that I'll be missing out on a lot more information that would make me a safer flyer. Also I'm not sure why you have to continuously try and prop yourself up with comments such as you most likely allowed me to find my drone. You did no such thing. Paint Rock Drones gave me useful information in a civilised way which I thoroughly appreciate and because of that I'm a lot more likely to take what he says on board in comparison to the people who thought they'd give themselves a little ego boost because they're perhaps more experienced in something. Your last comment is even more ridiculous than anything else you said because a 4 year old would be able to infer that the 'haha' obviously signifies that I'm joking, as well as being able to realise I'm not actually Spiderman and don't have the ability to carry out that activity even if I wasn't joking.

Thanks you Paint Rock Drones for your assistance and being a nice, inclusive person

 

[Paint Rock Drones]

(Corrected after I noticed the Australian rules cited above look very similar to FAA rules)
Rules aside, it really isn't a good idea to run your batteries so low that you have to force-land (or over-ride a forced landing). The LiPo batteries in our drones are not built to be fully discharged. You will shorten the life of your battery if you regularly run it down to 10% or lower. Search for a battery thread in this forum if you are interested in the details. But also, even with something as light as a mini, risking a forced landing in a place where it might land on someone is a safety issue.

I hope you do stick around. There are lots of knowledgeable folks here. In defense of PhiliusFoggg, he knows a great deal more than I do about reading logs, and he was also trying to help.

 

[MARK (LI)]

Alright pal I've got better things to do than argue with people online but let's just understand what's going on here. So I've had the drone for probably less than a month, so I suppose I am what you referred to as a 'noob'. In fact, this is the first drone forum I've ever engaged in. Because of that, perhaps I was somewhat ignorant of the rules which of course is my fault. But given my experience here and the berating you've so happily given out, which i can only imagine is due to the need to make yourself feel big and superior, I don't think I'll be returning any time soon. That being the case I'm sure that I'll be missing out on a lot more information that would make me a safer flyer. Also I'm not sure why you have to continuously try and prop yourself up with comments such as you most likely allowed me to find my drone. You did no such thing. Paint Rock Drones gave me useful information in a civilised way which I thoroughly appreciate and because of that I'm a lot more likely to take what he says on board in comparison to the people who thought they'd give themselves a little ego boost because they're perhaps more experienced in something. Your last comment is even more ridiculous than anything else you said because a 4 year old would be able to infer that the 'haha' obviously signifies that I'm joking, as well as being able to realise I'm not actually Spiderman and don't have the ability to carry out that activity even if I wasn't joking.

Thanks you Paint Rock Drones for your assistance and being a nice, inclusive person

@PhiliusFoggg is a known and respected member here ...you can leave if you want....it will be your loss....if you find this drone, it is likely going to be in bad condition...if you get a new one....you are probably going to lose that one, too if you continue the practices that Phillius has described to you...you may be better off calming down...re reading what he told you....absorb it and learn something that could really help you going forward ...if you realized the severity of your infractions...and how they effect everyone who flies a drone ....you would appreciate his critique