Lost P4P+

[aPpYe]

It seems the forest ate my brand new P4P+ ... I took off, and made a beeline straight towards some antennae (which I am learning may not have been a good idea?) that were about 2.5 miles from and 1300 feet above the home point. The drone lost connection at about 8300 feet from me, so still more than a mile from the antennae. It does not seem to have attempted a return to home. This happened a couple of days ago now, and I went to the location that was indicated by the last instant recorded on the flight log from the controller (a very long, strenuous hike, through thickets, poison oak, etc) and did not find it. I had full line of sight to the drone (though I could not actually see it because it was too far away), and I know it was still several hundred feet above the trees and over a thousand feet above me when I lost connection.

As you can see from the log, I had 83% battery at takeoff. It attempted a "smart" return to home at 5m 44.6s, but it was only at 64% battery at that point, so I figured I could push on. A couple minutes later, it lost connection completely and I never saw it again.

...I thought that 8300 feet should be small potatoes for this drone on a clear day with line of site. The lost connection did not seem right to me... What really surprised me was that it did not make any attempt to return to home (well, it never reconnected) and the drone was more or less lost forever. We have a prediction of rain coming up this evening, so I am thinking it is a final death knell ... If I don't find it by today, I guess I have some accessories I can put bullet holes into...

Anyway, I have attached the flight log. I am hoping someone can tell me what happened...

 

[Fly Dawg]

1300 feet above the home point.

Your first big mistake was attempting this flight at this long distance and taking off at only 83% Battery. There is no way you would
have had enough remaining power to return. The second one, was at 05:44 in to the flight and you ignored the battery warning which said " REMAINING BATTERY IS ONLY ENOUGH FOR RETURN TO HOME. RETURN HOME NOW. NOTE: There is no indication in the log that you initiated an RTH. Had you allowed RTH at that point you would still have your aircraft. The last and most important one was flying at over 1000ft in altitude which is an extreme violation of FAA and AMA guidelines. You most likely will not find anything in this data set to help you locate the aircraft. It most likely "autolanded" due to low battery. I am sorry about loosing the aircraft, but I think there is no question here that this was nothing short of Pilot error. There were no indications of any flight anomolies and once you loose connection, you lose data. So what you have is what you have.

 

[msinger]

Here's your uploaded flight log:
DJI Flight Log Viewer - PhantomHelp.com

 

[Fly Dawg]

ADDENDUM: The theory being that when you ignored the RTH warning and continued on and after you lost signal, under normal circumstances the Aircraft would have auto initiated RTH. BUT being the fact that the FC had already calculated there was only enough battery power to perform RTH, at that point, it went right to autoland at critical battery. Where that location is would be guesswork, especially so at over 1000ft in altitude where winds could be unpredictable, and could have drifted the Aircraft during autoland.

 

[msinger]

BUT being the fact that the FC had already calculated there was only enough battery power to perform RTH, at that point, it went right to autoland at critical battery.

When the remote controller signal disconnects, the aircraft will RTH (using the default setting in DJI GO), land, or hover. Assuming the OP did not change that setting, it would have attempted to fly back to the home point until the battery reached the critically low level. The aircraft would never jump right to auto land if it's set to RTH.

 

[Fly Dawg]

When the remote controller signal disconnects, the aircraft will RTH (using the default setting in DJI GO), land, or hover. Assuming the OP did not change that setting, it would have attempted to fly back to the home point until the battery reached the critically low level. The aircraft would never jump right to auto land if it's set to RTH.

Correct, but in this circumstance, the FC had already calculated the power remaining was ONLY enough to Return to Home at the 5:44 mark. The OP ignored this apparently, and continued on. My point being, that if the FC had already calculated that value at the 5:44 mark, then most certainly once the OP lost signal, it would re-calculate and determin that there was NOT enough power to perform RTH, hence it went straight to autoland.

 

[RunningWithScissors]

Wow! Don't know where to even begin with this one. Red flags everywhere. I'm taking a chance that one of the moderators will remove this post but, clearly you overestimated your skills as a pilot, and overestimated your Phantom's ability to compensate for poor judgement as well. The P4P is a very capable machine but, sadly, it's not idiot proof as you've discovered. As Fly Dawg said, it is what it it.

 

[msinger]

My point being, that if the FC had already calculated that value at the 5:44 mark, then most certainly once the OP lost signal, it would re-calculate and determin that there was NOT enough power to perform RTH, hence it went straight to autoland.

I'm following you. However, that's not how the FC works.

 

[msinger]

A couple minutes later, it lost connection completely and I never saw it again.

Do you remember what you did as soon as you lost the live view on your remote controller? Did you immediately release the sticks? Attempt to continue to fly?

 

[Fly Dawg]

However, that's not how the FC works.

After some thought, I am in agreement. So we can safely assume that even after the FC knows that there is not enough battery to perform RTH, that it will initiate anyway and autoland someplace on the return flight at critical battery. This would leave 2 options in this scenario as possibilities without more data to go on. The OP either had loss of signal set for hover, or for land. Otherwise, judging from where the signal was lost, the AC would have had enough power to return, at least to the point of signal re-connect. Again, all assumptions. One thing for sure, if the AC did indeed attempt RTH, it had plenty of altitude to do so.

 

[msinger]

judging from where the signal was lost, the AC would have had enough power to return, at least to the point of signal re-connect

Right, I'm thinking the same thing. As long as the OP did not shut down the remote controller, it should have at least made it far enough to reconnect.

@aPpYe, do you recall changing this setting in DJI GO?

 

[sar104]

I'm a little suspicious that this event might have been due to a loss of power. There were some minor signal issues prior to the end of the log, but nothing that suggested an imminent disconnect. On the other hand, the end of the recorded flight coincides with a maneuver that caused a rapid and large change in aircraft pitch:

At 368 s the aircraft was flying in sport mode 18 m/s (40 mph) with full forward elevator, when the pilot applied nearly full throttle. As a result the pitch changed from -34° to -7° in one second, and was still rising when the log ended. That maneuver has, in the past, caused poorly secured batteries to disconnect/eject.

It's not conclusive at all but the coincidence of the maneuver with the abrupt end of the log is certainly suggestive.

 

[aPpYe]

I made sure that setting was set to return to home last I went in there. Curiously, when looking at that area in the controller now, the setting isn't even there... I am not sure what FC is. Once the connection was lost, I immediately set the controller down, thinking I would once again regain connection as it did RTH. Obviously I never did. Why would it just blink out like that at 61% battery?

The reason I pushed the automated RTH, is that I figured it only burned through 21% battery, and that I should still have plenty for my own RTH... The idea was to take it to 50%, then return to home. The first time it initated an automatic RTH, it still had over 40% battery when it got back, and it wasn't even that far. The function seemed a bit over cautious to me on that flight, so I figured I could push it a little. The goal wasn't really to make it all the way to the antennae, so much as to see what lay in that direction.

As far as the FCC violation, I figured I was okay, because I made sure that it was only a few hundred feet above the actual ground level from where it was. I made sure to fly straight (no elevation gain) until the trees go a little uncomfortably close, then would to some altitude gain, and kept repeating this procedure. The idea was to scale up the side of the mountain. This is still a violation?

Still, if it attempted a RTH, shouldn't I have gotten the signal back?

 

[aPpYe]

... I guess I did miscalculate the elevation thing by a little. The total altitude (adding from the home point of 3050 feet) would put the drone at about 4090 feet. The point it lost altitude has an elevation of 3566 feet, so 524 feet. You are right about the violation... Or is it that I am not allowed to rise above 400 feet from the home point? If so, that's a pretty low ceiling, considering flying around in the mountains...

I thought I was being pretty respectful ...

 

[aPpYe]

...That maneuver has, in the past, caused poorly secured batteries to disconnect/eject....

So perhaps I did not make sure the battery was securely in place? While this is certainly possible, I have always tried to make sure it was clicked in place securely...

 

[bsartist]

...The last and most important one was flying at over 1000ft in altitude which is an extreme violation of FAA and AMA guidelines. ...

I don’t think he was 1,000 ft AGL. Just a above home point. I assumed he was flying over rising terrain.

 

[bsartist]

... I guess I did miscalculate the elevation thing by a little. The total altitude (adding from the home point of 3050 feet) would put the drone at about 4090 feet. The point it lost altitude has an elevation of 3566 feet, so 524 feet. You are right about the violation... Or is it that I am not allowed to rise above 400 feet from the home point? If so, that's a pretty low ceiling, considering flying around in the mountains...

I thought I was being pretty respectful ...

It looks like Fly Dawg May have just misread your post. The guideline is 400ft above ground (or obstruction). So if you climbed over rising terrain and stayed within 400 ft AGL then you were within guidelines. At 524 ft you are technically outside the guidelines. But as a hobbyist they are guidelines. Not regs.

Personally I wouldn’t go scolding you for that alone. But you have to think about safety in the airspace. Since you could no longer see the aircraft I think that makes flying above the guidelines worse from a safety perspective. You probably can’t avoid any other manned aircraft like a helo should you run into one.

 

[Fly Dawg]

It looks like Fly Dawg May have just misread your post. The guideline is 400ft above ground (or obstruction)

No, I did not misread the post, I misread the altitude data ( Did not consider terrain AGL ) and had that in my head.

 

[aPpYe]

the main question I have at this point would be where a good point to find the craft would be. Flying at 40mph, with perhaps a 5-8mph tailwind, and considering it is 524 feet above the ground, how far beyond the last known position would you suggest looking? I went perhaps a couple hundred feet beyond the flight path, but perhaps I should have gone further? Honestly, I am loath to make that hike again!

 

[bsartist]

No, I did not misread the post, I misread the altitude data ( Did not consider terrain AGL ) and had that in my head.

Ahh. Ok. His initial post did mention 1300ft above the home point. Thought maybe that’s what you were referring to. Understand now.