P3 Crash During Litchi Mission (CFIT)

[JBG]

Litchi uses F mode for waypoints

Sent from my Nexus 6 using Tapatalk

 

[JickMagger]

So if it won't RTH properly or soon enough on critical battery in Waypoints mode, then just have to fly missions short enough that it is certain the copter will have time to return. And another reason to always fly on a full battery.

For getting back home I always set a ~250' high waypoint over the launch location, then a ~20 foot waypoint over the launch location to allow it to descend safely and then I manually descend it to my hand.

 

[Air Ontario]

Can someone explain HOW litchi would use WIFI vs same digital method GO uses?

or even if it can/does!

(doesn't)

The only time Litchi uses wifi, that I am aware of, is upon the initial opening of the Litchi app. It does so in order to connect to DJI servers, at least as far as I know from my limited beta testing of Litchi for iOS.

However I have had a mission enter F-Atti and drift. I placed the PAF selector switch back into P(GPS) and brought it back and restarted the mission and it completed successfully. I have had some issues the last two days with intermittent and severe interference at my launch site which I have never had before, so that likely explains the initiation of F-Atti and the drift.

I also had a mission where the waypoint altitude was set to decrease between two waypoints(the last two) and it did exactly as I programed it to do and dropped altitude.

 

[Wacker2611]

"F" mode is where the issue lies (position 1). If it is not using "F" mode then it would not be affected.

RTH doesn't really apply in Litchis waypoint mode, as the bird will always complete the mission regardless of signal (assuming you've done your calculations correctly). But in Litchi if you switch from f to p and engage RTH it works just fine, controller on or off.

 

[wawakool]

A little advice I had one experience a similar problem. But the fault was mine, I was using litchi for a mission. I did a mistake with my last way point.

I had 5 way point
Way point 1 = 80m, way point 2 = 90m, way point 3 = 90m, way point 4 = 90m and accidentally set way point 5 to 10m

I did not re checked if all the way point was programmed correctly and what happened was during the mission after the craft passed on way-point 4 it started to dropped altitude very rapidly as between way point 4 and 5 there was only about 50mt between them.

When on the mobile screen i saw that altitude was dropping i immediately switch from F mode to P mode. So the mission was immediately abort and the craft hover the place where it was, gain control back and bring it back safe.

Little advises that i can share to those flying litchi mission is
1. Don't Panic
2. To re check you way point altitude, and keep your last way point higher that any tress etc.
3. Do not fly longer where your remote will loose signal if you have problem with RTH
4. As soon as you have any problem with a mission switch immediately to to P mode get control back and if you don't know where you are hit the RTH button or use the home lock, pull your joystick backward it will bring your craft automatically to you.
5. Always verify the option selected if aircraft loose signal. Make you that return to home is selected. Because if accidentally you click on Hover(if signal lost it will hover) if you click on land craft it will land the crack so make sure that RTH is selected.

Note that what ever you are doing into F mode if there is any problem just switch to P mode. It will cancel all immediately and let your craft hover where it is. So that you can bring it back or use the RTH button on the remote control.

If you do not switch to P mode you will not gain control of your aircraft it will keep on executing the mission or other thing you had programmed.

I fly with litchi for a couple of time now. And i had not problem with it, only problem i got was completely because of a mistake i did.

I hope that this can help litchi users.

Take care

 

[wawakool]

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

(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

A little advice I had one experience a similar problem. But the fault was mine, I was using litchi for a mission. I did a mistake with my last way point.

I had 5 way point
Way point 1 = 80m, way point 2 = 90m, way point 3 = 90m, way point 4 = 90m and accidentally set way point 5 to 10m

I did not re checked if all the way point was programmed correctly and what happened was during the mission after the craft passed on way-point 4 it started to dropped altitude very rapidly as between way point 4 and 5 there was only about 50mt between them.

When on the mobile screen i saw that altitude was dropping i immediately switch from F mode to P mode. So the mission was immediately abort and the craft hover the place where it was, gain control back and bring it back safe.

Little advises that i can share to those flying litchi mission is
1. Don't Panic
2. To re check you way point altitude, and keep your last way point higher that any tress etc.
3. Do not fly longer where your remote will loose signal if you have problem with RTH
4. As soon as you have any problem with a mission switch immediately to to P mode get control back and if you don't know where you are hit the RTH button or use the home lock, pull your joystick backward it will bring your craft automatically to you.
5. Always verify the option selected if aircraft loose signal. Make you that return to home is selected. Because if accidentally you click on Hover(if signal lost it will hover) if you click on land craft it will land the crack so make sure that RTH is selected.

Note that what ever you are doing into F mode if there is any problem just switch to P mode. It will cancel all immediately and let your craft hover where it is. So that you can bring it back or use the RTH button on the remote control.

If you do not switch to P mode you will not gain control of your aircraft it will keep on executing the mission or other thing you had programmed.

I fly with litchi for a couple of time now. And i had not problem with it, only problem i got was completely because of a mistake i did.

I hope that this can help litchi users.

Take care

 

[razorseal]

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

WHAT lol... absolutely not! and I'm sure I wasn't the first one to say this.

 

[DAP-UAV]

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 stopped bothering pointing these things out. Too many believe it is just a toy and they can do whatever they want regardless. Too many believe the FAA has no say. Yes, DJI is targeting the consumer more than the commercial operator and is trying to make flying easier, but it still requires a pilot and a pilot's knowledge considering the capabilities of these UAV's. My opinion. There are now over 300,000 registered hobbyist. That's more than manned aircraft operating today. It seems to me that safety for some is an afterthought. OK I am done. You can attack me now.

 

[tclark333]

A little advice I had one experience a similar problem. But the fault was mine, I was using litchi for a mission. I did a mistake with my last way point.

I had 5 way point
Way point 1 = 80m, way point 2 = 90m, way point 3 = 90m, way point 4 = 90m and accidentally set way point 5 to 10m

I did not re checked if all the way point was programmed correctly and what happened was during the mission after the craft passed on way-point 4 it started to dropped altitude very rapidly as between way point 4 and 5 there was only about 50mt between them.

When on the mobile screen i saw that altitude was dropping i immediately switch from F mode to P mode. So the mission was immediately abort and the craft hover the place where it was, gain control back and bring it back safe.

Little advises that i can share to those flying litchi mission is
1. Don't Panic
2. To re check you way point altitude, and keep your last way point higher that any tress etc.
3. Do not fly longer where your remote will loose signal if you have problem with RTH
4. As soon as you have any problem with a mission switch immediately to to P mode get control back and if you don't know where you are hit the RTH button or use the home lock, pull your joystick backward it will bring your craft automatically to you.
5. Always verify the option selected if aircraft loose signal. Make you that return to home is selected. Because if accidentally you click on Hover(if signal lost it will hover) if you click on land craft it will land the crack so make sure that RTH is selected.

Note that what ever you are doing into F mode if there is any problem just switch to P mode. It will cancel all immediately and let your craft hover where it is. So that you can bring it back or use the RTH button on the remote control.

If you do not switch to P mode you will not gain control of your aircraft it will keep on executing the mission or other thing you had programmed.

I fly with litchi for a couple of time now. And i had not problem with it, only problem i got was completely because of a mistake i did.

I hope that this can help litchi users.

Take care

Wow - that's eerily similar to what happened in my mission! I thought all of my way points were the same height as the first one I set. It wasn't until after the mission that I saw the last way point was set so low, so I'm still not sure how I screwed that one up. I did plan the mission on my tablet, saved it, and then loaded it and flew it with my phone, so somehow in all of that something got off. I'll always check right before I fly next time - on the same device.

But thanks for the advice! Had I been more experienced with it, I would have switched to P mode as soon as I realized something was wrong. I'll definitely remember that in future flights.

 

[JerEl]

There are a lot of misunderstanding here regarding Litchi. I fly Litchi almost exclusively as I've had bad luck with the Go app crashing. For one thing, Litchi transfers the mission to the Phatom 3 prior to actually launching the mission.

After you hit the go button and the mission starts you can turn off the transmitter and it will perform the mission and go to to the last waypoint and hover waiting for a manual command. Not a smart thing to do but that's how it works. Anytime during the mission that you still have transmitter control you can switch to P-GPS mode and take manual control. If you switch to P mode and then after that you lose contact it will go into RTH mode. It will not automatically go into RTH while it's performing the mission.

However if the battery runs too low it will make a controlled landing where it is just like in P mode. Then if you have Flytrex you can go traipse through the woods and find it. That's why it's important to look at the mission details to insure you have enough battery to complete the mission. It does give a summary of the mission before you hit go. I only make missions 12 min. or less even with a fully charged battery, to be sure it can make it back to the last waypoint. I start and end with the waypoint higher than anything in my area (which is a 100' pine tree out near the front of my property) usually at 150' and rarely go lower than that except over a small lake at the back of my property where I sometimes dip down for some nice POV video. The last thing I check prior to starting a mission is to scroll each waypoint and recheck the altitude.

There is no SDK error from DJI regarding RTH in waypoint missions because it doesn't use RTH with the waypoints function. I feel totally comfortable flying with Litchi, more so than with the Go app since it's too much trouble setting up F mode flights and it crashes sometimes. I have recently moved to a Nvidia Shield Tablet instead of my Note 4 and neither have crashed since I've changed, but I lost my confidence in the Go app when using the Note 4.

That beeping the OP heard from the transmitter could have been a low battery warning on the transmitter. This whole thread making Litchi look bad was caused by self admitted pilot error not a DJI or Litchi error as are 98% of the reported crashes with P3s.

 

[AirSpace2016]

If Litchi does not think it can complete the mission it will RTH apparently this is built into the firmware. It will also do the RTH based on what you set not just auto land. Yes it will complete the mission in the event of signal loss or RC loss but RTH will still work. This is what the Lithi Devs have confirmed to me. Has anyone tested this ? The SDK mode is effected in Focus and Orbit modes with RTH but the chances of losing signal whilst in these modes are remote.

 

[artfuldodger]

I think you ran out of power. You went on a long flight. You started with 84% power. And ended with 26%. What are your settings for low power? 30%? That is what most people have.

Try flying your P3A near you in a hover using the Litchi software. When the power drops below 30% you should hear a beeping. Is that the sound you heard? I will bet it is.