From P to ATTI mode in a blink....why?

[hani7up]

Hi all. A question for the Phantom 4 experts
Today I had to shoot the interior of a Baroque style church. Of course there was no one there except for my self and my assistant.
Everything went as smooth as silk, and I flew "Vision Mode" as the drone couldn't get the GPS mode due to the structure of the church.
But when I started a different take near the choir and organ, my Phantom 4 went from P mode to ATTI mode without any prior notice, which almost ended up in a disaster.
Under what conditions would the drone automatically change the flight mode from P to ATTI? Did this happen because there was a lot of heavy metallic structure at the Choir (heavy iron cast gates, organ pipes, etc)?

 

[Fly Dawg]

Under what conditions would the drone automatically change the flight mode from P to ATTI? Did this happen because there was a lot of heavy metallic structure at the Choir (heavy iron cast gates, organ pipes, etc)?

That is quite possible. Did you have any compass error messages? If you are unsure you could share your flight log and we could tell you.

 

[hani7up]

That is quite possible. Did you have any compass error messages? If you are unsure you could share your flight log and we could tell you.

Thanks Fly Dawg. Sorry if the question appears to be silly but, where would I find the flight log?

 

[Fly Dawg]

where would I find the flight log?

They are in 3 different places on a P4, but the easiest to get in on your device that you fly with. See this link and follow the instructions. If you would like others to look, share a link back here to the uploaded file.

DJI Flight Log Viewer - Phantom Help

 

[hani7up]

They are in 3 different places on a P4, but the easiest to get in on your device that you fly with. See this link and follow the instructions. If you would like others to look, share a link back here to the uploaded file.

DJI Flight Log Viewer - Phantom Help

OK. Copped the folders Flight Records and Flight Log to my desktop. Shall I upload, here, the "many" text files included so that you guys can check them?

 

[hani7up]

They are in 3 different places on a P4, but the easiest to get in on your device that you fly with. See this link and follow the instructions. If you would like others to look, share a link back here to the uploaded file.

DJI Flight Log Viewer - Phantom Help

Here's a link to both folders:

Flight records - Google Drive

 

[Fly Dawg]

Shall I upload, here, the "many" text files included so that you guys can check them?

No. What you need to do is see the link I provided above. Upload the correct flight file to there. Then share a link to that back here.

 

[svjobeth]

Will be interesting to see what the logs show.

I had a similar issue with my P4P+ and it seems to have been caused by my take-off point being on a steel reinforced concrete pad. My mode switches happened in flight, well after take-off, but also well away from any metal objects/structures.

After several flights in an area well away from any steel/iron - and I mean well away, as in a 100yds/30m or more - I've had no further (similar) issues.

 

[Meta4]

I flew "Vision Mode" as the drone couldn't get the GPS mode due to the structure of the church.
But when I started a different take near the choir and organ, my Phantom 4 went from P mode to ATTI mode without any prior notice, which almost ended up in a disaster.
Under what conditions would the drone automatically change the flight mode from P to ATTI? Did this happen because there was a lot of heavy metallic structure at the Choir (heavy iron cast gates, organ pipes, etc)?

To get back to the original question, ..
With the flight mode switch in the P-GPS position:
If your Phantom has a good sky view it uses GPS
If it can't get enough satellites for P-GPS mode but is within 10 metres of the ground and the surface has a recognisable pattern or texture and lighting conditions are good enough ...
.. the Phantom will use P-Opti mode to maintain horizontal position.
But if the VPS system is unable to help because Phantom is out of VPS range (>10 metres high) or or the surface pattern is indistinguishable or the light level is too low, the Phantom has nothing left to maintain horizontal position and it will be in Atti mode.

 

[hani7up]

Thank you all.
I now understand what happened and am grateful for all your feedbacks: thanks to Fly Dawg, Meta4, Svjobeth....
Atti is an excellent support in such special conditions and if I know this before flying I would have taken it easy. Anyway, will practice in Atti mode too, just in case, in open spaces, to get used to it.
Thank you again guys, I really appreciate it.

Photoshop I haven't downloaded any aerial shots yet, but will soon do, hopefully. Meanwhile, my portfolio is at www.500px.com/hani7up, if you'd like to check it up