P4P crashed while Litchi Mission (no relative to terrain altitude)

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Last weekend I went to fly my first mission with Litchi (latest version) on iPad 4 mini. I scouted the terrain, made some notes, prepared all via the hub on their website, saved the mission and once on site loaded the mission to the P4P. the altitude seemed all fine with enough headroom over the surrounding threes.

I knew the terrain was going uphill (aprox. 12 meters) and I took of flying at 40 meters above take off point.
Watching the Ipad screen I saw that I was loosing height, actually the terrain was rising. But the P4P did not climb as he supposed to according the mission. At certain point I lost connection (distance 900 meters, which was also the point where the P4P would do a 360° view of a monument and then return over the same path to the home point). I was ready to abort the mission but transmission was lost that second. Bummer.

Waiting for over 3 minutes I knew things went wrong. I took the car and drove to the monument. the P4P was crashed into a large three, the only one on the terrain, go figure. Because the P4P did not climb the clearance above the three was not enough and my P4P caught the three really in the top (2 meters would be enough). Normally I would have had over 10 meters clearance.

I'm really sad because I can not recover the P4P. It's way up and a branch sticks through the P4P landing gear. The three is to high and to slim to climb in, also the terrain is not suitable to take some lift and go from there.

I've been looking in Google Earth and when exporting the kml-file from there into Litchi I see the waypoints rising when terrain rises but I keep asking myself why my P4P did not climb according the mission. Is the app really taking relativity to ground into account ? I lost my faith in Litchi for the moment and will be flying controlling the craft myself for the time being.

I know some will react that I have to keep eye contact all times. I know this is mainly pilot error but i.m.h.o the app failed to I guess. It all looks nice on paper or on screen but I lost a lot of money in the progress. Hard lesson learnt. Ordered a new P4P ...
 
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Hello Mavician,

Sorry to hear about your crash! I hope you find a way to recover it.

My first thought is, when you say copter lost height when you expected it to climb - are you 100% certain the mission wasnt acutually configured this way? Maybe something went wrong with KML export - I know it isn't easy and Google Earth does have options to import height relative to sea level or ground.
That being said, ltichi height instructions are always relative to take off point, not relative to terrain! That takes some careful math when setting it up in mission hub while double-checking in G earth.

Sebastian
 
Last weekend I went to fly my first mission with Litchi (latest version) on iPad 4 mini. I scouted the terrain, made some notes, prepared all via the hub on their website, saved the mission and once on site loaded the mission to the P4P. the altitude seemed all fine with enough headroom over the surrounding threes.

I knew the terrain was going uphill (aprox. 12 meters) and I took of flying at 40 meters above take off point.
Watching the Ipad screen I saw that I was loosing height, actually the terrain was rising. But the P4P did not climb as he supposed to according the mission. At certain point I lost connection (distance 900 meters, which was also the point where the P4P would do a 360° view of a monument and then return over the same path to the home point). I was ready to abort the mission but transmission was lost that second. Bummer.

Waiting for over 3 minutes I knew things went wrong. I took the car and drove to the monument. the P4P was crashed into a large three, the only one on the terrain, go figure. Because the P4P did not climb the clearance above the three was not enough and my P4P caught the three really in the top (2 meters would be enough). Normally I would have had over 10 meters clearance.

I'm really sad because I can not recover the P4P. It's way up and a branch sticks through the P4P landing gear. The three is to high and to slim to climb in, also the terrain is not suitable to take some lift and go from there.

I've been looking in Google Earth and when exporting the kml-file from there into Litchi I see the waypoints rising when terrain rises but I keep asking myself why my P4P did not climb according the mission. Is the app really taking relativity to ground into account ? I lost my faith in Litchi for the moment and will be flying controlling the craft myself for the time being.

I know some will react that I have to keep eye contact all times. I know this is mainly pilot error but i.m.h.o the app failed to I guess. It all looks nice on paper or on screen but I lost a lot of money in the progress. Hard lesson learnt. Ordered a new P4P ...
First, to clarify. When you say the birds did not climb as programmed, do you mean that the height at the second waypoint was higher than the second? If so, by how much and how far apart were the WPs? Also, did you have straight or curves set in Path Mode in the mission settings? The manual is unclear about how changes in altitude are handled when 'curved lines' are set, but other functions don't work if you don't have 'straight lines' set. Can you estimate how far from the second WP you were and how high the bird was compared to the programmed WP height?
 
Sorry to hear of your loss, always hate to hear such stories.

You can compare the waypoint altitudes in your mission to the flight log stored on your control device to verify that the aircraft altitude matched the programmed waypoints (and that waypoints were close enough together to properly resolve rapid terrain changes), and if the aircraft didn't follow the program then I'm sure Litchi would like to see the data. But more likely they did and some sort of human error was involved, and unfortunately such a mistake is very easy to make. It always seems to be that one tree or that one building. :(

Many here recommended a manual 'pre run' before the automated flight if at all possible to check for what you may not see with mission planning tools.
 
KML planning always scares me. Sometimes Google has an odd offset that doesn't work out so well. This animated GIF shows where the bird flies inside a mountain even though the KML wall shows it going over it. Needs a lot more buffer clearance.

Flight Plan in Google Earth.gif
 
I know what happened I think. Litchi programmed the altitude of the climb on the hill but didn't take the trees into the factor. Litchi only judges the height raised on the actual ground. It doesn't do it for trees as obviously trees grow so it will be different each time. Really sorry to hear about your loss. That's why I never trust the automatic terrain change on litchi. It did calculate for me a few times when I used it, but I still bottled out and decided to go at a set height then lower the height slightly for the next mission.

Don't give up tho mate. You can still get it back. It's not the trees stopping you from getting your drone back, it's your imagination stopping you getting it back. Think really carefully... Have a beer or two, try not to get to worked up and calmly think of a way of getting back, tree surgeon could get it? Can you get a ladder? No such thing as "impossible" only "puzzles"

Can you give us a google earth link or some kind of pic so we can see what the terrain is like? Then we can all pitch in and come up with a plan. Your not the first to be in this situation and their has been lots of rescue missions where the bird did get back to the owner. Don't give up mate. We will work this out [emoji4]
 
Thanks for all the replies. I have a friend who also flies drones and we're discussing on how to get it back. It has been pouring rain for the last two days so the P4P will be soaked. The tree is very small in diameter but high and all branches are pointed vertically. Almost impossible to climb. Next problem is the location. It's on a area where a classified monument resides so we just can not do what we want or law enforcement will come. Also the rules flying drones in my country are far more restricted since last year than the rest of Europe. We only can fly drones less than 1 kg on a max height of 10 meters over own property unless we follow lessons, pay taxes, get an exam and pass, to get a licence flying up to 5 kg with max altitude of 45 meters in open space. That alone sets one back 1500$ US while in all other countries one can fly rather free following basic rules. As you see the risk of going there in public doing crazy stuff will set me back a lot more than losing a drone, how hard it might be right now.

As for the tech stuff, what I also don't understand is the collision avoidance. I got the 4 Pro also for having sensors on all 4 sides. I was not speeding, just few m/sec so they should have worked. I've seen YouTube videos where the P4P does a heck of a job avoiding stuff like trees, branches, etc.. and not only walls. Why did mine just flew into the tree without even hesitating? All question I don't find answers for at the moment. But anyhow, I will certainly fly with line in side in the future !!
 
You might find a tree trimmer willing to use such skills and equipment to retrieve your valuable bird for a fee...off the books and under a covert operation, of course.
 
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Well I've been lying in bed wondering I might set up a rescue mission. I believe the P4P can lift about 3 times it's own weight. I could hook up some fishing wire that will snap if to much tension is applied. Attach a rather wide angled hook and try to hover over the tree top keeping a safe distance. With the camera facing down I should have a pretty good view and when I choose a day without wind I might get an opportunity to lift the P4P out of the tree. It sits only 1 meter from the top and the branches are thin and flexible and also pointing vertical so the odds could be in my favor. Any thoughts on my plan ?
 
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Unless I've missed it, roughly how high is the quad in the tree? I had a helo stuck in a tree about 30 mtrs up and I walked across the road to the council depot, gave them a carton and they gently nudged the base of the tree with a loader until it came down. **** good catch by me and the workers had a beer at my misfortune. Not sure if that would be an option for you given where it is, but you may have a friend with a large ute with a bull bar than could do the same (under cover of darkness). With regards to OA, I have never relied on it to react to small branches despite what I have seen on YouTube and use the relative to ground feature on Litchi and add 10 mtrs as I don't trust the numbers either on google or on the app.
 
I'm curious. Why do so many folks use Litchi or similar products? I fly with a terrific hood on my iPad Air 2 and fly FPV. I can see the terrain, make adjustments on the fly, circle an interesting point control my altitude etc. Am I missing something? Definitely not knocking any such type of autonomous flight but just curious :)
 
yeah buddy, hang a wire fishing line down w/ a treble hook...take it slow...you don't want two birds up there. I've rescued cheaper drones from trees by throwing billy club size sticks at the branches. I threw em underhand, spinning, and if you hit the branch the bird just might hop off and you can catch it. Admittedly, haven't thrown anything at my Phantom. Hit branches with it, but luckily haven't gotten stuck.
 
Good luck with recovering the drone. Use your new P4P to take a picture of your old P4P stuck in a tree and we will give you ideas on how to recover it.
 

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