Landing

[msinger]

After that full throttle up has no effect; it remains in the FORCE_LANDING state, descends and lands regardless of throttle.

Isn't that only because the VPS was still detecting the Mavic was close to the ground?

 

[BudWalker]

Isn't that only because the VPS was still detecting the Mavic was close to the ground?

Probably. I looked at a flight from early Nov where FORCE_LANDING was in effect but the VPS was no longer reporting. Full throttle in that situation cancelled FORCE_LANDING.

FORCE_LANDING doesn't happen just because the VPS is reporting and full negative throttle. VPS has to be .5 meters or less for FORCE_LANDING to happen. So full throttle has the desired effect when VPS is reporting and above 0.5 meters (according to VPS). @Andrew F had reported that autolanding (I assume he meant the FORCE_LANDING state) was cancelled while below 0.5 meters and that was not the same as what I was seeing.

 

[msinger]

@Andrew F had reported that autolanding (I assume he meant the FORCE_LANDING state) was cancelled while below 0.5 meters

I don't think that's possible. If it is though, that's a flight log we should check out.

 

[mfarris2]

OK Guys and Gals,....I am new to this and just learned how to get to my logs and flight records. I'm still trying to figure out how to get them uploaded to this site. From my iPad Mini,....I have flight records in a .txt file format.
As the instruction video showed myself, I uploaded these files to Healthy Drones. However I could only bring those back as a .csv or .kml file.
Those could not be uploaded onto this forum. So all I could do was upload the text files.
Again,.....thanks for all your help.
Sorry it took so long to get these posted,...(if they even help) I had a difficult time figuring all of this out.

I believe you will find the issue in all three flights. But especially in the second and third flight.

 

[BudWalker]

I believe you will find the issue in all three flights. But especially in the second and third flight.

Looking at the third flight at about 68 seconds. The mystery is why the VPS is reporting even though the altitude is 58.8 meters. When full back throttle is applied the Mavic switches to FORCE_LANDING state. Later, at about 74 secs VPS has stopped reporting and full throttle is applied. This causes the FORCE_LANDING to be cancelled.

It's fortunate that VPS stops reporting after FORCE_LANDING. If it weren't for that full throttle would not have cancelled FORCE_LANDING.

@msinger gave good advice here
Landing
I.e. until it's determined why VPS is reporting when it shouldn't don't use full negative throttle to descend. Having said this I plan to never use full negative throttle since there have been cases where VPS keeps reporting and full throttle has no effect.

 

[Andrew F]

I don't think that's possible. If it is though, that's a flight log we should check out.

No. I was referring to auto landing that initiates when close to ground with full stick down. How do you replicate forced landing? I'm happy to test. I guess I could set my battery forced landing specs. Yes. I'll do that today. But a depleated battery would show on the logs and wasn't reported in this instance. Still worth testing.

 

[BudWalker]

No. I was referring to auto landing that initiates when close to ground with full stick down. How do you replicate forced landing? I'm happy to test. I guess I could set my battery forced landing specs. Yes. I'll do that today. But a depleated battery would show on the logs and wasn't reported in this instance. Still worth testing.

That's the one. FORCE_LANDING is the name of the state that shows in the .txt or .DAT when full back throttle is applied and VPS is reporting 0.5 meters or less. You shouldn't have been able to cancel FORCE_LANDING with full throttle. Any chance you could post the .txt for this? Either upload to @msinger 's log viewer here or attach the .txt to a post.

 

[Andrew F]

That's the one. FORCE_LANDING is the name of the state that shows in the .txt or .DAT when full back throttle is applied and VPS is reporting 0.5 meters or less. You shouldn't have been able to cancel FORCE_LANDING with full throttle. Any chance you could post the .txt for this? Either upload to @msinger 's log viewer here or attach the .txt to a post.

Will do. Gonna be an hour or so until I can get back to my Mavic. I'd like to test the other landing scenario too as they must have different parameters. But I believe I've cancelled the emergency version in the past as well.

 

[mfarris2]

Looking at the third flight at about 68 seconds. The mystery is why the VPS is reporting even though the altitude is 58.8 meters. When full back throttle is applied the Mavic switches to FORCE_LANDING state. Later, at about 74 secs VPS has stopped reporting and full throttle is applied. This causes the FORCE_LANDING to be cancelled.
View attachment 8706
It's fortunate that VPS stops reporting after FORCE_LANDING. If it weren't for that full throttle would not have cancelled FORCE_LANDING.

@msinger gave good advice here
Landing
I.e. until it's determined why VPS is reporting when it shouldn't don't use full negative throttle to descend. Having said this I plan to never use full negative throttle since there have been cases where VPS keeps reporting and full throttle has no effect.

Guys I want to thank you for your input. Some i admit I do not understand. I know I started to descend to get a closer look at the island and the remote started telling me it was landing. I attempted to do the same thing a couple of different times over different areas with the same results. Seemed to me that every time I tried to descend,...the Mavic wanted to land. Can someone in plain English tell me what I did wrong? Some of the abbreviations I am still learning. IE VPS
Again everyone,...thank you very much for all your time and effort with this. It is greatly appreciated by someone new and unexcited to this hobby,...albeit I myself would be classified as old. Lol

 

[Andrew F]

Guys I want to thank you for your input. Some i admit I do not understand. I know I started to descend to get a closer look at the island and the remote started telling me it was landing. I attempted to do the same thing a couple of different times over different areas with the same results. Seemed to me that every time I tried to descend,...the Mavic wanted to land. Can someone in plain English tell me what I did wrong? Some of the abbreviations I am still learning. IE VPS
Again everyone,...thank you very much for all your time and effort with this. It is greatly appreciated by someone new and unexcited to this hobby,...albeit I myself would be classified as old. Lol

In short, you did nothing wrong. It seems that your Mavic believed it was not way up in the air, but right near the ground. It is unclear why without more information. It may not happen again. Be sure your downward cameras and sonar sensors are clean and that the DJI app shows them "green" before flying. You should be able to test over and over again in your yard to make sure there is no major problem. There is ongoing debate whether water causes this sort of anomalous behavior. You "may" want to disable your Visual Positioning System if this happens again. Just look up how to do that separately. You really need to be familiar with all of the menu options anyway. Good luck!

 

[mfarris2]

In short, you did nothing wrong. It seems that your Mavic believed it was not way up in the air, but right near the ground. It is unclear why without more information. It may not happen again. Be sure your downward cameras and sonar sensors are clean and that the DJI app shows them "green" before flying. You should be able to test over and over again in your yard to make sure there is no major problem. There is ongoing debate whether water causes this sort of anomalous behavior. You "may" want to disable your Visual Positioning System if this happens again. Just look up how to do that separately. You really need to be familiar with all of the menu options anyway. Good luck!

Thank you so much for your help and support. I did fly it again this evening,.....but not over water. I flew out about 1500 feet before signal got weak. So I turned it around and brought it back. I raised and lowered the Mavic several times with no issues this time.
Got it! VPS = Visual Positioning System. Read about that in the manual. Now understand the abbreviation.Again,.....thank you for your help.

 

[Andrew F]

Thank you so much for your help and support. I did fly it again this evening,.....but not over water. I flew out about 1500 feet before signal got weak. So I turned it around and brought it back. I raised and lowered the Mavic several times with no issues this time.
Got it! VPS = Visual Positioning System. Read about that in the manual. Now understand the abbreviation.Again,.....thank you for your help.

By the way. I have tested it many times and when you are in autolanding mode, if you stick up, it will exit that mode and respond. Just don't panic! Haha.

 

[mandyjr]

By the way. I have tested it many times and when you are in autolanding mode, if you stick up, it will exit that mode and respond. Just don't panic! Haha.

Actually that's not exactly right. When the landing problem happened to me I did stick up and nothing I tried everything and nothing worked.

 

[Andrew F]

Actually that's not exactly right. When the landing problem happened to me I did stick up and nothing I tried everything and nothing worked.

No. Actually what I said is exactly right. You had an anomalous situation. Probably your RC was malfunctioning. But if all is in order, it will respond.

 

[Logger]

Thats odd. Mine must be misbehaving too then. Stick up = no exit.
Mine will go into Autoland/Forced Landing below 0.5m as expected, with full down throttle. The problem is it will do so whilst travelling at high speed which I find undesirable. When I see visually it is has transferred to Auto landing whilst in forward motion, going to full throttle does not catch it in time and it often lands. I have been playing with this on flat sports field so it is reasonably safe to skid land while in motion.

Does toggling to Sport mode change the flight state and stop Forced Landing?

EDIT.
Just checked full up throttle does not stop mine from Auto Landing.
However toggling the mode switch either way from Sport to P or P to Sport does.

 

[HFMan]

That doesn't sound normal at all- so abnormal I would not even fly it until you find what is causing it. Is your battery way low when this happens?

 

[Andrew F]

Thats odd. Mine must be misbehaving too then.
Mine will go into Autoland/Forced Landing below 0.5m as expected, with slight down throttle. The problem is it will do so whilst travelling at high speed which I find undesirable. When I see visually it is has transferred to Auto landing whilst in forward motion, going to full throttle does not catch it in time and it often lands. I have been playing with this on flat sports field so it is reasonably safe to skid land while in motion.

Does toggling to Sport mode change the flight state and stop Forced Landing?

EDIT.
Just checked full up throttle does not stop mine from Auto Landing.
However toggling the mode switch either way from Sport to P or P to Sport does.

Very interesting. There must be other variables / settings interacting then. There are so many settings, we really need someone from DJI I think to explain why the behavior is not consistent. I uploaded a flight to BudWalker and he verified my behavior. Maybe you could do the same with yours.

 

[Logger]

Here is a quick video I just made. 3 landing attempts. First two interrupted by toggling mode switch. First P to S, Second S to P. Third attempt, as soon as autoland starts, full up stick and it does not stop landing.

VPS in feet so 1.5' is the 0.5m trigger. Flight mode displayed at centre top border. You can see the three instances of LANDING getting annunciated in the FMA. first two immediately get cancelled while third with full throttle does not. Wil pull the log.

 

[Logger]

Here you go. Teal is Forced Landing (Autoland), blue is sport.



You can clearly see how toggling between sport and P either way takes it out of Forced landing and in the last instance how Full throttle does not.

 

[Logger]

That doesn't sound normal at all- so abnormal I would not even fly it until you find what is causing it. Is your battery way low when this happens?

No it is on a Full battery and not critical battery autoland.