DJI Phantom 4 Malfuntion - Climbed On Its Own, Would Not Descend

[captainmilehigh]

It may be wise to gather up all information on that incident, (the Phantomhelp flight logs, your videos, and @FlyDawg’s charts etc) and start a claim with DJI. Even though the bird is out of warranty, it may be worth your time and effort to try for a positive result.

I’d still speculate that the R/C may have been the problem. Possibly a stuck/corrupted transmitter that did not allow RTH to initiate when activated.

DJI may want to test the R/C as well as look at the flight logs. Maybe you’ll get lucky and they’ll send you another bird AND a new R/C.

Can’t hurt to try. Good luck[emoji106]

 

[gerickson9301]

It may be wise to gather up all information on that incident, (the Phantomhelp flight logs, your videos, and @FlyDawg’s charts etc) and start a claim with DJI. Even though the bird is out of warranty, it may be worth your time and effort to try for a positive result.

I’d still speculate that the R/C may have been the problem. Possibly a stuck/corrupted transmitter that did not allow RTH to initiate when activated.

DJI may want to test the R/C as well as look at the flight logs. Maybe you’ll get lucky and they’ll send you another bird AND a new R/C.

Can’t hurt to try. Good luck[emoji106]

I'm trying for this. So far I've been on the phone with DJI for about 2 hours collectively. My "case" has been escalated and I'm now in contact with a DJI manager. I am waiting on another call back from them.

Fingers Crossed

 

[Fly Dawg]

Possibly a stuck/corrupted transmitter that did not allow RTH to initiate when activated.

If you look back at the chart in post #10, RTH was transmitted to the AC. The theory being that since the AC was at the max allowed altitude, and the throttle apparenty stuck at 100%. The AC could not initiate the return. RTH is very slow, and the high rpm's could not be reduced to allow the return at that altitude with the stuck throttle. Even being that obviously it was far above the set RTH altitude by the OP, the aircraft will not try and descend to RTH altitude if it is above that point per the way RTH is designed. That's what I am suggesting. Even if RTH had worked, it would not be able to descend to land. Those are my thoughts.

 

[MotorCycle-Man]

I had something quite similar to this happen to my P3 SE.....i got the drone back But it was a scary 4 minutes ! it for No reason went to RTH and rose and moved and descended and landed ....and many commented on the flight log.....Thanks to guys here like "Fly Dawg" ! and many others too.

 

[captainmilehigh]

If you look back at the chart in post #10, RTH was transmitted to the AC. The theory being that since the AC was at the max allowed altitude, and the throttle apparenty stuck at 100%. The AC could not initiate the return. RTH is very slow, and the high rpm's could not be reduced to allow the return at that altitude with the stuck throttle. Even being that obviously it was far above the set RTH altitude by the OP, the aircraft will not try and descend to RTH altitude if it is above that point per the way RTH is designed. That's what I am suggesting. Even if RTH had worked, it would not be able to descend to land. Those are my thoughts.

Yep, I understand your reasoning. What are your thoughts on my suggestion in my earlier post for the OP to just switch off the R/C during the ascent. Do you suppose the bird would have initiated RTH and stopped climbing due to the lost link with the R\C ?

 

[Fly Dawg]

Do you suppose the bird would have initiated RTH and stopped climbing due to the lost link with the R\C ?

That is a distinct possibility, under normal circumstances shutting off the RC will result in RTH. It should stop the climb at that point. I would have to go back and look at the altitude settings to check where the AC was when RTH was commanded, but if I recall without looking, I believe he was too close to the home point at those times, so it would have landed. Your suggestion would be be quite viable assuming that this "stuck" RC throttle is indeed true, but the only way to confirm without a doubt would be to see the AC .dat. But obviously that is not likely to happen.

 

[captainmilehigh]

That is a distinct possibility, under normal circumstances shutting off the RC will result in RTH. It should stop the climb at that point. I would have to go back and look at the altitude settings to check where the AC was when RTH was commanded, but if I recall without looking, I believe he was too close to the home point at those times, so it would have landed. Your suggestion would be be quite viable assuming that this "stuck" RC throttle is indeed true, but the only way to confirm without a doubt would be to see the AC .dat. But obviously that is not likely to happen.

I tested my P3S this morning to see what it would do in a similar situation. About 200 feet away from home point at 100 feet altitude I went to full throttle up for maybe 10 seconds and held it there. Then switched off the R/C. It took a few seconds to react, but it did stop the ascent eventually and turned for Home at that altitude (since it was above my set RTH altitude) and flew home. This was with my P3S. I don’t have a P4, but I would think it would react the same.

It would almost be worth the swim to recover the bird for that AC .dat file.

 

[Fly Dawg]

I don’t have a P4, but I would think it would react the same.

They all will react the same. But my primary point was, this aircraft was at the MAXIMUM altitude limit at almost 2000ft and could not fly higher, although it appears it was trying. Here is another chart, I didn't put up before but you can see the RTH actions and Low battery RTH actions in comparison with the battery levels and altitude.

 

[captainmilehigh]

Yep, I understand your point. Those charts tell a lot of what the a/c was doing.

 

[Fly Dawg]

Yep, I understand your point.

I do agree with the RC shutdown, but there would have been no way for the OP to know at the time that the throttle was "stuck", so that would most likely not have been considered in the emergency actions. This is one that I have not seen, so I am sure there are no "procedures" for such an event.

 

[J&W]

It seems to me that anytime you have a RC failure you should turn it off to initiate RTH, unless it's in ATTI mode?

 

[Clockman]

This is a very interesting case. It's not often we see the loss of a aircraft that was not due in some way to operator error. It appears this was some sort of transmitter error and I hope DJI does something to help the OP. I will follow this and please keep us updated.

 

[Meta4]

It seems to me that anytime you have a RC failure you should turn it off to initiate RTH, unless it's in ATTI mode?

It doesn't matter if it was switched to atti mode.
If the Phantom is receiving GPS satellite signals, it will use GPS to RTH.

 

[Fly Dawg]

It doesn't matter if it was switched to atti mode.
If the Phantom is receiving GPS satellite signals, it will use GPS to RTH.

This is one I can not verify. Un-tested. However, it would make logical sense that if the RC is still connected to the AC, but the RC is in ATTI and RTH is initiated by the pilot and GPS is still good that the aircraft will NOT execute an RTH, due to the commanded ATTI mode. On the flip side, if the RC is switched to ATTI, and then the RC is turned off, and the above scenario is true, then the aircraft WILL execute RTH due to loss of signal. Does that make sense? As I said, unverified and this would be a bit of an odd case. An "Out of the Box" thought quite honestly.

 

[With The Birds]

This is one I can not verify. Un-tested. However, it would make logical sense that if the RC is still connected to the AC, but the RC is in ATTI and RTH is initiated by the pilot and GPS is still good that the aircraft will NOT execute an RTH, due to the commanded ATTI mode. On the flip side, if the RC is switched to ATTI, and then the RC is turned off, and the above scenario is true, then the aircraft WILL execute RTH due to loss of signal. Does that make sense? As I said, unverified and this would be a bit of an odd case. An "Out of the Box" thought quite honestly.

If the AC has GPS lock RTH command from the remote works.... I have tested it. This makes sense. For one of the firmware/ software engineers to expect electing to fly in ATTI night suggest your happy for RTH not to work would be very concerning.

 

[Fly Dawg]

For one of the firmware/ software engineers to expect electing to fly in ATTI night suggest your happy for RTH not to work would be very concerning.

This makes no sense. Maybe it is my interpretation of your wording, however the way this is worded it make absolutely no sense. As for the other comment, if you read the post thoroughly, there were 2 different scenarios mentioned in what you quoted. This is what I have not tested and most likely will not.

 

[Fly Dawg]

f the AC has GPS lock RTH command from the remote works.... I have tested it.

You tested this with the RC switched to ATTI ? And not P-GPS? Just clarifying that.

 

[With The Birds]

This makes no sense. Maybe it is my interpretation of your wording, however the way this is worded it make absolutely no sense. As for the other comment, if you read the post thoroughly, there were 2 different scenarios mentioned in what you quoted. This is what I have not tested and most likely will not.

I was responding to your comment “it would make logical sense that if the RC is still connected to the AC, but the RC is in ATTI and RTH is initiated by the pilot and GPS is still good that the aircraft will NOT execute an RTH”. RTH does work as expected in those circumstances.

 

[Fly Dawg]

I was responding to your comment “it would make logical sense that if the RC is still connected to the AC, but the RC is in ATTI and RTH is initiated by the pilot and GPS is still good that the aircraft will NOT execute an RTH”. RTH does work as expected in those circumstances.

You answered before the next post.....But that is a better clarification. So I am assuming that you have tested this with the RC switched to ATTI, prior to initiating an RC iniatiated RTH command, correct? If so, then that answers my question.

 

[With The Birds]

You tested this with the RC switched to ATTI ? And not P-GPS? Just clarifying that.

Absolutely.... My intent was simply to assist you in clarifying your, as stated, untested assumption.