P3 Crash During Litchi Mission (CFIT)

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(I sped up parts of the video, but the crash scene is real-time)

Aftermath pic: Amazon Cloud Drive

Sad to report, but I had my first crash this morning. I planned a simple mission to a park and back, but things didn't go well. It was supposed to take 8 minutes to go there and back, but after about 8 minutes had passed, my controller suddenly started beeping in this pattern - beep, pause, beep, pause - over and over.

I had never heard this before. I've had issues with missions where it would return to home early and I would get that RTH beeping sound, but this wasn't in RTH mode. It was just beeping strangely. I listened to that for about 30 seconds when sudddenly I heard it reporting that the altitude was dropping (the whole mission was supposed to maintain 269 feet). I started trying to raise the altiude but it didn't seem to be responding - the last report I hear was that it was at 90 feet. By then, it was within a couple of houses away from me and I heard it chopping through trees. I knew it was over.

Luckily, my battery didn't pop out and I was still seeing a picture from it upside down in a tree. I also had a GPS location, so I walked down to my neighbor's and was able to find it in bushes between the 2 adjacent houses down from me.

Besides some broken, dirty props, it seems ok - although I haven't tried to take it back up yet. Looking at the flight plan, it only recorded what seems to be the part where I had signal, so it's hard to tell where it went wrong. But at the end of the flight, something obviously malfunctioned, causing it to descend rapidly before my home point. Watching the video, it came down much faster than it does when returning to home. The only time I touched the controller was to try to increase altitude, so that speed wasn't coming from me.

Here's my concern - I've had very little success flying missions with the Litchi app. Half of the time, my missions end early on and my P3A goes into RTH mode. It's made it back fine every time except now, but something is triggering RTH mode early, and it's not because of the battery. The longest mission I've planned for is about 8 minutes, and that's always with little wind (less than 11mph). I've also had issues with the video cutting out during flight and the video files being corrupted. I've experimented with the DJI Go app and Litchi, and with different Android devices, and almost all flights have had some kind of issue. That's why I'm thinking my bird must be defective.

If anyone has any thoughts or suggestions, I'd be happy to hear them. Otherwise, I'm about to try to send this back and get a replacement, or try another model or brand.

FYI, here's what I was using when it crashed:
Phone: Samsung S5 (SV-G900V) - Android v5.0
Litchi app: v2.7.1
P3 FW: v1.6.004

Flight plan:
Mission Hub - Litchi

HealthDrones log:
HealthyDrones.com - Innovative flight data analysis that matters

HealthyDrones showed an average wind speed of 250mph. There were no tornoados in the area, so that definitely wasn't correct. My UAV app showed wind speeds of only 10mph:
Amazon Cloud Drive
 
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Since the litchi app was using 2.4ghz wifi/telemetry transmissions to the drone it interfered with your transmitters signal with gave control latency...

You should use the DJI go app since it connects to the drone thru the transmitter directly.
Unlike the litchi app which uses wifi signals


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Looked like it really sped up and started dropping after going over those high power lines
 
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The music had me crying through the entire flight, knowing it was going to crash. Sorry for your loss.
 
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I sped up some of the video during flight, but at the end it is at real-time speed. I would think flying at 260 feet would be high enough not to get any interference over the power lines, but who knows. I've flown over them a couple of times before at about that height and had no issues.
 
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Your altitude on way point 9 was 82m then on way point 10 it was 5m. From way point 9 it would suddenly decrease in altitude and continue until it got to 5m at way point 10, what was your reason for doing this or am I reading this mission wrong?
 
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So you didn't issue any descend commands but it was obviously in a controlled descent.
Your logs should clearly show what happened in this case. Post your logs.

Not that this has anything to do with your crash....
But another guy posted about his crash yesterday and his battery information was similar to yours......
I'm wondering if you're on the same FW as he is.

Major Deviations ™
Major deviation is when a cell differs more than 0.07v from the other cells.
Please note that normal batteries can have a few of these.
An abnormal battery will:
A) Have most of the major deviations in one cell
B) There will be multiple major deviations per minute, and more than 10 total
C) The deviations continue longer than 1 minute
If your battery shows all symptoms (example, another) then this is considered a more severe case of an inefficient battery and may impact the battery life.
If your battery has only 1-4 instances on the same cell, don't worry too much about it. If it has 5-10 instances - then continue to track and make sure it does not degrade:


Flight Time Deviation Cell 1 Cell 2 Cell 3 Cell 4
00m 44s 0.073v 3.752v 3.831v 3.825v 3.828v

Again, just pointing out an interesting similarity.
 
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Since the litchi app was using 2.4ghz wifi/telemetry transmissions to the drone it interfered with your transmitters signal with gave control latency...
Looked like it really sped up and started dropping after going over those high power lines
My thoughts exactly ... two negatives compounded.
 
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What do you mean???


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Since the litchi app was using 2.4ghz wifi/telemetry transmissions to the drone it interfered with your transmitters signal with gave control latency...

You should use the DJI go app since it connects to the drone thru the transmitter directly.
Unlike the litchi app which uses wifi signals


Sent from my iPad using PhantomPilots mobile app
Well, that's a new one on me!
 

LuvMyTJ

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It is a pleasure to welcome you to the Phantom Pilots forum. I hope that you will take advantage of the benefits that come with membership and that you will be able to use the forum for the exchange of innovative ideas and as a resource for current developments in Phantom quadcopter’s.

All I can say is wow. This is why we are required to register, flights like this right here. It is so fortunate no one was hurt. Why are you flying BLOS missions in an urban neighborhood? Especially when you have documented issues prior to this using a third party app. Very irresponsible on your part... people, houses, cars and high tension power lines were a few of the things you risked. You are using 3rd party apps which has a known RTH problem (all third party apps do until there is a firmware upgrade). I am glad your bird was relatively unharmed but you should really reevaluate your flying locations. This type of flying is why we are all under scrutiny by the public and the FAA. Reserve flights like this to open rural areas or over open water. Please be more responsible with your aircraft.

Please take a look at this link - Know Before You Fly

I am also surprised by the fact no one else here has called you out on this flight. That shows me that either people are afraid to say something or that they don't see the complete disregard for safety. If the latter is true we are in for a world of hurt in this hobby.
 
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Again way point 9 = 82m and waypoint 10 = 5m. The mission was instructed to decrease the height after way point 9 which matches your healthy drones log if I am reading this right? Connection should not matter it should just fly the mission can anyone firm if I am reading his litchi mission correctly?
 
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I'm still learning this but looks like you lost connection before the power lines
 
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Well...I see that now - just not sure how that happened. I always start my first waypoint high so that each new waypoint will have the same height, so I don't know why the last one is set so low. I double checked them all before I flew it, so I don't know when that would've gotten changed. Oh well, maybe it was my fault somehow. Good news is I just took it back up with new props and it seems to be just fine. Maybe this should be the end of my auto-pilot flying with Litchi.
 
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Besides what LovMyTJ said (he said it better than I could), you simply made a mistake and programmed your last waypoint too low.

Waypoint 9 = 269'
Waypoint 10 = 16'

The distance between waypoints was 977' so you were dropping 1' vertically for every 4' horizontally. You probably made it about 400' from Waypoint 9 until you hit the treeline at around 100' or so.

Sorry for your mistake. Be safe. Dont be the guy that makes the news.
 
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Yeah man, I hear you. You live and you learn. Will definitely be more careful and not so trusting next time! Thanks for the advice/support!
 

ianwood

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Since the litchi app was using 2.4ghz wifi/telemetry transmissions to the drone it interfered with your transmitters signal with gave control latency...
No. Maybe it does on the P2V. It sure doesn't on the P3.

Looked like it really sped up and started dropping after going over those high power lines
No. Power lines do not cause that kind of result.

My thoughts exactly ... two negatives compounded.
Two negatives that don't exist and wouldn't cause this result.

Your altitude on way point 9 was 82m then on way point 10 it was 5m. From way point 9 it would suddenly decrease in altitude and continue until it got to 5m at way point 10, what was your reason for doing this or am I reading this mission wrong?
Yes. We have a winner. CFIT.
 
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It is a pleasure to welcome you to the Phantom Pilots forum. I hope that you will take advantage of the benefits that come with membership and that you will be able to use the forum for the exchange of innovative ideas and as a resource for current developments in Phantom quadcopter’s.

All I can say is wow. This is why we are required to register, flights like this right here. It is so fortunate no one was hurt. Why are you flying BLOS missions in an urban neighborhood? Especially when you have documented issues prior to this using a third party app. Very irresponsible on your part... people, houses, cars and high tension power lines were a few of the things you risked. You are using 3rd party apps which has a known RTH problem (all third party apps do until there is a firmware upgrade). I am glad your bird was relatively unharmed but you should really reevaluate your flying locations. This type of flying is why we are all under scrutiny by the public and the FAA. Reserve flights like this to open rural areas or over open water. Please be more responsible with your aircraft.

Please take a look at this link - Know Before You Fly

I am also surprised by the fact no one else here has called you out on this flight. That shows me that either people are afraid to say something or that they don't see the complete disregard for safety. If the latter is true we are in for a world of hurt in this hobby.
I got reamed because I tried to warn people of the 3rd party app issue. See post #8 and all the users responding to that on this thread:
Litchi autonomous flight: lost my bird
I didn't think people could be so rude when we are just trying to help. Apparently autoflightlogic posted updated information in the forum but they didn't send out an updated email. I agree that these waypoint missions are being used wrong, that is why in the DJI Go app they require you to fly the mission first, then it can be saved as a waypoint mission. We all need to be the guardians of our freedoms regarding this hobby/profession. Someone should start a multirotor club similar to the AMA that actually has our best interests in mind.
 

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