I was ready to classify my P3P a "Fly Away" and jump into the car to keep it in range. Then I saw it was in P-ATTI mode which is not good.  I flipped the mode switch from P to F thinking I would regain control but my iPhone continued to display P-ATTI.  Once I realized I was in ATTI I regained my composure and managed to fly it back.  HealthyDrones does not show any discrepencies with the GPS or Compass.  Can anyone tell me how to troubleshoot this?

Even though you were in GPS mode, it is possible to lose GPS lock for any number of reasons.  When this happens the aircraft goes to ATTI mode, or manual positioning flight.  Fortunately you recognised this and didn't panic, and was able to fly it back manually.  That is a skill that should be practiced by everyone for exactly this reason.   Fortunately this wasn't complicated by combining it with high altitude or strong winds.  

How many satellites were being reported when it reported P-ATTI?  If you share the Healthy Drones link for the flight we can have a look at the whole situation for you.   It is hard to say why you lost GPS lock.  Were you standing in an open field, were there trees nearby blocking the view of the sky, were there tall buildings on the horizon, etc.?  If the GPS situated in the middle/top of the aircraft body is obstructed or if its view of the sky is blocked (storm clouds, tree branches etc), it can declare a satellite unreliable and not use it for calculating its position.  If you get enough of these, your reliable satellite count can fall below the minimum, say 8, and the aircraft decides it would be bad to rely on so few satellites and switches to ATTI (P-ATTI means your mode switch is still in (P)GPS mode and will resume P mode if sufficient satellite connections return).  Generally this shouldn't be a big problem, just move somewhere with a better view of the sky, gaining altitude generally works well.  Unfortunately that seems counter-intuitive when you are worrying that it is out of control and you want to put it on the ground as fast as possible .

Healthydrones is next to useless for looking into an incident to see what really happened.
If you want to see what happened, go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.

I'm wondering what you saw on your app.
It may have said Atti Mode but I don't think it it would ever show P-Atti mode.
P-Atti mode is the way Healthydrones labels P-GPS mode.

endotherm Posted at 2017-2-19 05:04
Even though you were in GPS mode, it is possible to lose GPS lock for any number of reasons.  When this happens the aircraft goes to ATTI mode, or manual positioning flight.  Fortunately you recognised this and didn't panic, and was able to fly it back manually.  That is a skill that should be practiced by everyone for exactly this reason.   Fortunately this wasn't complicated by combining it with high altitude or strong winds.  

How many satellites were being reported when it reported P-ATTI?  If you share the Healthy Drones link for the flight we can have a look at the whole situation for you.   It is hard to say why you lost GPS lock.  Were you standing in an open field, were there trees nearby blocking the view of the sky, were there tall buildings on the horizon, etc.?  If the GPS situated in the middle/top of the aircraft body is obstructed or if its view of the sky is blocked (storm clouds, tree branches etc), it can declare a satellite unreliable and not use it for calculating its position.  If you get enough of these, your reliable satellite count can fall below the minimum, say 8, and the aircraft decides it would be bad to rely on so few satellites and switches to ATTI (P-ATTI means your mode switch is still in (P)GPS mode and will resume P mode if sufficient satellite connections return).  Generally this shouldn't be a big problem, just move somewhere with a better view of the sky, gaining altitude generally works well.  Unfortunately that seems counter-intuitive when you are worrying that it is out of control and you want to put it on the ground as fast as possible  .

Litchi Flight Log => http://www.phantomhelp.com/LogViewer/NWV8KP3TI7PXIFNK44CC/

I constantly had 16-17 satellites while flying in an open field with nothing between me and the P3P.  Lately performing a compass calibration would resolve erratic flight but not this time.  I felt totally out of control while it would speed up and turn even when I was not touching the sticks.  I have an unopened set of landing gear with compass that I can try.  Should I also replace the GPS unit?

J Finch Photogr Posted at 2017-2-26 10:19
Litchi Flight Log => http://www.phantomhelp.com/LogViewer/NWV8KP3TI7PXIFNK44CC/

I constantly had 16-17 satellites while flying in an open field with nothing between me and the P3P.  Lately performing a compass calibration would resolve erratic flight but not this time.  I felt totally out of control while it would speed up and turn even when I was not touching the sticks.  I have an unopened set of landing gear with compass that I can try.  Should I also replace the GPS unit?

The flight mode was changing between P-OPTI and P-ATTI many times throughout the flight.  I'm not sure what P-OPTI mode is, I would think there should be a P-GPS mode showing in there somewhere.  (It did show F-GPS for 100ms at 3:25 and 4:39, and a couple of seconds at 5:04).  I'm not sure why it was switching back and forth during the flight.  It reported receiving a steady stream of satellites, but perhaps the GPS module is somehow defective. The rest of the data looks normal.  It was holding altitude pretty well at 164ft for a lot of the flight, but seemed to have trouble holding horizontal location, consistent with no GPS.  In ATTI mode it will feel like it is out of control and be at the mercy of the wind, which you experienced, so that is actually normal.  The area was fairly open, but I wonder if it has something to do with being in the middle of a wind farm?  There may be buried cables in the ground that may upset your equipment.  Do you have your aircraft body plastered with stickers or vinyl wrap?  Have you ever calibrated the aircraft IMU?  Do you have the same thing happen at other locations?  It sounds like you may have a bad compass calibration if you are constantly having to calibrate it to resolve erratic flight, normally it will also warn of compass errors though.  Replacing hardware is a bit drastic at this point, just make sure you do a full calibration in an interference free area first and reset all the sensors.

Labroides Posted at 2017-2-19 05:54
Healthydrones is next to useless for looking into an incident to see what really happened.
If you want to see what happened, go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.

Good app. Any way to save the upload to show everyone for an opinion on a flight gone wrong?

Johnnyv Posted at 2017-3-2 11:00
Good app. Any way to save the upload to show everyone for an opinion on a flight gone wrong?

After you have loaded the flight in question you can share a link to the flight data by clicking on the green icon at the upper right of the main box. You can select what data to share, but the defaults are probably the bare minimum.  I advise people to also select kml (to visualise the flight path in 3D on Google Earth) and csv (so the entire flight data is available to view in a spreadsheet like Excel, it contains important stuff like stick input values and headings that aren't shown on a pretty coloured line on a map).

endotherm Posted at 2017-3-2 11:42
After you have loaded the flight in question you can share a link to the flight data by clicking on the green icon at the upper right of the main box. You can select what data to share, but the defaults are probably the bare minimum.  I advise people to also select kml (to visualise the flight path in 3D on Google Earth) and csv (so the entire flight data is available to view in a spreadsheet like Excel, it contains important stuff like stick input values and headings that aren't shown on a pretty coloured line on a map).
[view_image]

That is healthydrones.com. The one I' talking about is the link below.

http://www.phantomhelp.com/LogViewer/Upload/

Phantom help gives some different info than my healthy drones uploads.

I've had problems with Litchi and the P3, constant switching between GPS and ATTI , getting stuck in ATTI with many satellites, completely reversed controls after aborting a way point mission. It's a great app but sometimes goes a bit mad. I have found when switching between P and F pause for 10 seconds in ATTI stops most of the GPS problems. Doesn't help your issue but something to keep in mind.

Johnnyv Posted at 2017-3-2 11:00
Good app. Any way to save the upload to show everyone for an opinion on a flight gone wrong?

You simply copy the URL of the Phantomhelp report, which you can share and it will show the details anytime for anyone.

Labroides Posted at 2017-3-2 13:34
You simply copy the URL of the Phantomhelp report, which you can share and it will show the details anytime for anyone.

http://www.phantomhelp.com/LogViewer/Y907V28STKUWTRTJFHHB/

Please feel free to comment. The flight was video recorded as well.

Johnnyv Posted at 2017-3-2 15:29
http://www.phantomhelp.com/LogViewer/Y907V28STKUWTRTJFHHB/

Please feel free to comment. The flight was video recorded as well.

Lots of YAW, speed, and compass errors.  Then switched to atti mode.

Johnnyv Posted at 2017-3-2 15:29
http://www.phantomhelp.com/LogViewer/Y907V28STKUWTRTJFHHB/

Please feel free to comment. The flight was video recorded as well.

All those compass errors are a concern, do you calibrate your compass often?

Johnnyv Posted at 2017-3-2 15:29
http://www.phantomhelp.com/LogViewer/Y907V28STKUWTRTJFHHB/

Please feel free to comment. The flight was video recorded as well.

The satellites diminishing down to three, then zero, is concerning too.

Johnnyv Posted at 2017-3-2 11:56
That is healthydrones.com. The one I' talking about is the link below.

http://www.phantomhelp.com/LogViewer/Upload/

Sorry, I was confused which one you thought was a "good app".  I've also noticed there can be discrepancies between them sometimes and I like to have both available.  They are both pretty good for telling you what went wrong, not necessarily why.  That takes a bit of experience and detective work.

Geebax Posted at 2017-3-2 21:24
All those compass errors are a concern, do you calibrate your compass often?

Each flight. No Problems with my P3 pRo doing the same thing. I have learned on this site just to check the calibration however.

blackcrusader Posted at 2017-3-2 20:16
Lots of YAW, speed, and compass errors.  Then switched to atti mode.

It didn't happen. I think it malfunctioned.

Johnnyv Posted at 2017-3-3 03:55
It didn't happen. I think it malfunctioned.

You may not have switched to ATTI mode, but the aircraft will do so itself if it encounters compass errors.

Geebax Posted at 2017-3-3 13:40
You may not have switched to ATTI mode, but the aircraft will do so itself if it encounters compass errors.

I switched to ATTI mode mid flight from the first flight with only a couple of exceptions. Each time I was able to land it in ATTI mode safely. The last flight was not controllable. Conditions were great with light winds.