Second Time Out - Complete Loss Of Control

SteveAikens · Aug 1, 2015

Just back in from trying the second flight with this P3P. I took a friend out to the football field at a school just outside town, to show him how simple it was to handle basic flight.

After going down my checklist, doing calibration and making sure everything checked out. I decided to show him how simple it was to just use Auto-Takeoff to get to a hover.

I slide the button on the iPad, "the home point has been updated, take-off", the P3P immediately goes to full power and promptly flips over on the ground. Absolutely zero control from the App. I hand off the TX to my buddy, grab the P3P by the landing gear and finally get to the battery to pull it out. Press/quick release/press and hold does not shut the bird down. Fortunately, the only apparent damage is to props.

This system was updated to 1.26 on 6/16/2015. It flew on 6/18/2015 with no problems. It's been in its case since then, until I took it out this morning to charge the TX and one of the batteries. Nothing else was changed.

Now the App says NO MC DATA ACCELEROMETER FAILED. Told me to shut the drone off and restart. Did that several times. Told me to check connections on the gimbal. Checked them. Removed the gimbal to unplug and plug it back in - all to no avail.

Tried to do the update on the bird again and it failed, saving it already had that version of the firmware.

Unfortunately, it looks like I'm one of those with firmware issues. There's simply no other explanation at this point.

Very disappointed at this point. Knowing what DJI "Support" is like makes it no better.

III% Streve · Aug 1, 2015

That sounds more like you took off from grass and it drifted slightly as it lifted. Always take off from a solid surface! Grass on take-off and landing can cause all sorts of issues. Try an IMU calibration to fix the strange errors.

dedstik · Aug 1, 2015

Steve...

This might sound weird, but try this:

You need to do a full calibration. When I was flying my Blade QX350 Horizon Hobbies put out a video recommending that you place your 350 in a refrigerator freezer for about 15 minuted prior to preforming a complete re-calibration.

Other P3 flyers have reported good success with this technique. Some have used their refrigerator which usually has more room. Some have placed their P3 over an air conditioning duct for 30 min.

Try to cool the P3 for 10 - 30 min. depending on the environment and then place the quad an a completely level surface and perform an IMU calibration, and then compass and gimbal calibration, etc.

DO NOT cool the battery !! Props off always.

This might work for you.

Good luck.

:harry

SteveAikens · Aug 1, 2015

III% Streve said:
That sounds more like you took off from grass and it drifted slightly as it lifted. Always take off from a solid surface! Grass on take-off and landing can cause all sorts of issues. Try an IMU calibration to fix the strange errors.

Took off from the top of the Microcopter hard case - just like last time I flew it, taking off and landing several times to get the feel of it.

SteveAikens · Aug 1, 2015

dedstik said:
Steve...

This might sound weird, but try this:

You need to do a full calibration. When I was flying my Blade QX350 Horizon Hobbies put out a video recommending that you place your 350 in a refrigerator freezer for about 15 minuted prior to preforming a complete re-calibration.

Other P3 flyers have reported good success with this technique. Some have used their refrigerator which usually has more room. Some have placed their P3 over an air conditioning duct for 30 min.

Try to cool the P3 for 10 - 30 min. depending on the environment and then place the quad an a completely level surface and perform an IMU calibration, and then compass and gimbal calibration, etc.

DO NOT cool the battery !! Props off always.

This might work for you.

Good luck.

:harry

Nothing to lose at this point. I'll give that a try tomorrow. I'll post back. Thanks.

RoyVa · Aug 1, 2015

Good luck, connect to the assistant and see if it show any errors. Then do the full calibrations. When your back up and running check those motors shafts to be sure they turn free and none wher damage or bent in the crash.

Garrie · Aug 1, 2015

SteveAikens said:
Just back in from trying the second flight with this P3P. I took a friend out to the football field at a school just outside town, to show him how simple it was to handle basic flight.

After going down my checklist, doing calibration and making sure everything checked out. I decided to show him how simple it was to just use Auto-Takeoff to get to a hover.

I slide the button on the iPad, "the home point has been updated, take-off", the P3P immediately goes to full power and promptly flips over on the ground. Absolutely zero control from the App. I hand off the TX to my buddy, grab the P3P by the landing gear and finally get to the battery to pull it out. Press/quick release/press and hold does not shut the bird down. Fortunately, the only apparent damage is to props.

This system was updated to 1.26 on 6/16/2015. It flew on 6/18/2015 with no problems. It's been in its case since then, until I took it out this morning to charge the TX and one of the batteries. Nothing else was changed.

Now the App says NO MC DATA ACCELEROMETER FAILED. Told me to shut the drone off and restart. Did that several times. Told me to check connections on the gimbal. Checked them. Removed the gimbal to unplug and plug it back in - all to no avail.

Tried to do the update on the bird again and it failed, saving it already had that version of the firmware.

Unfortunately, it looks like I'm one of those with firmware issues. There's simply no other explanation at this point.

Very disappointed at this point. Knowing what DJI "Support" is like makes it no better.

You're lucky. I crashed my P3P on the 2nd day of ownership and broke the gimbal.
I had to fork out another usd539 for the replacement gimbal

dedstik · Aug 1, 2015

Video of "quad in the freezer" technique for calibrating. The HH guy references the pressure sensor (baro) but many swear by this technique for IMU calibration.

As always, WMMV.

:harry

envisionabove · Aug 1, 2015

P

dedstik said:
Video of "quad in the freezer" technique for calibrating. The HH guy references the pressure sensor (baro) but many swear by this technique for IMU calibration.

As always, WMMV.

:harry

Putting it in the refrigerator only achieves a faster startup nothing other wise. It helps cool the bird from having long warm ups when doing MUI calibrations.

ScottyT · Aug 1, 2015

How unusual. Some crazy things happen with these birds; there will always be a reason and it's likely in the logs but you'd have to get DJI to analyse them for you.

I'd start with a cold IMU as per this video

Do a compass calibration after that, in a different location free from any metal.

SteveAikens · Aug 2, 2015

ScottyT said:
How unusual. Some crazy things happen with these birds; there will always be a reason and it's likely in the logs but you'd have to get DJI to analyse them for you.

I'd start with a cold IMU as per this video

Do a compass calibration after that, in a different location free from any metal.

There isn't even a reference in anything on the card to the bird even being started yesterday. No hidden files on the card either. That's actually another symptom of the failure.

I plan to try to work it out again later today. Frankly, I don't hold a lot of hope.

EDIT: Just tried again. Same thing.

Acceleration (g): x: -16.02 y:0.33 z:-1.02 Mod: 16.06

Can't clear it no matter what I try.

4wd · Aug 2, 2015

If the accelerometer error persists, it can sometimes be fixed by a hard tap on the shell.
It's a mechanical sensor which can stick in a minor crash

timmer · Aug 2, 2015

4wd said:
If the accelerometer error persists, it can sometimes be fixed by a hard tap on the shell.
It's a mechanical sensor which can stick in a minor crash

Many people have been able to recover from a stuck accelerometer. Please see this thread.

SteveAikens · Aug 2, 2015

I am completely stunned! I'm up and running again.

suqsid.bobmail [on the DJI forum]

After following your suggestion of a good "smack" in the appropriate location on the bird with my hand several times to no avail, I recalled reading on one of the forums, of a user that like me, had no success. He then tried "a good smack" with a rubber mallet.

Having nothing to lose in my eyes, I decided to grab a rubber mallet and give it a couple thumps and try the IMU calibration again.

SUCCESS!

Thanks to all for your suggestions. Special thanks to suqsid.bobmail. You're dead on the money with your suggestions and locations.

Duke007down · Aug 2, 2015

Wow, glad to see you're up and running again but I can't help but notice this was only your second flight on your quad. The only time I have ever seen a quad do a total flip is when the propellers are installed incorrectly (black on silver, silver on black) . Not saying this was the case in your situation, just a thought.

Sent from my HTC One_M8 using Tapatalk

SteveAikens · Aug 2, 2015

?? How can you install them backwards? They're right/left threaded and color coded to the spindles. I did verify they were on correctly when I took them off. They were unusually tight. First time I flew, when I packed up, I was able to remove the props by hand, though they were quite tight. This time, they were very tight, requiring the wrench to remove three of them.

Part of my checklist:

Transmitter Firmware current
Drone Firmware current
Inspect for obvious defects
Batteries fully charged
Propellers Sil on Sil/Blk on Blk
Propellers tightened properly
Remove camera lock and foam
ND filter on/off?
SD card formatted/in camera
etc.

I do appreciate your suggestion and will continue to make certain they're on properly. Again, I don't understand how someone can actually get them on the wrong spindles. I guess maybe it's possible but how could you tighten them down properly without stripping the threads out of the plastic?
¯\_(?)_/¯

Fplvert · Aug 2, 2015

I just can't understand the attraction to this auto takeoff feature.

jcknows0 · Aug 2, 2015

Duke007down said:
Wow, glad to see you're up and running again but I can't help but notice this was only your second flight on your quad. The only time I have ever seen a quad do a total flip is when the propellers are installed incorrectly (black on silver, silver on black) . Not saying this was the case in your situation, just a thought.

Sent from my HTC One_M8 using Tapatalk

There was actually a guy on here last weekend that did an auto takeoff into a flip (posted the video). He was lucky because he was about 10 feet from a massive cliff. There clearly is a callibration error in these instances. I'm not sure about the freezer technique but I've been fairly lucky with only doing 2 IMU callibrations with my P3 (initial and after firmware update)

Slone Starkey · Aug 3, 2015

dedstik said:
Steve...

This might sound weird, but try this:

You need to do a full calibration. When I was flying my Blade QX350 Horizon Hobbies put out a video recommending that you place your 350 in a refrigerator freezer for about 15 minuted prior to preforming a complete re-calibration.

Other P3 flyers have reported good success with this technique. Some have used their refrigerator which usually has more room. Some have placed their P3 over an air conditioning duct for 30 min.

Try to cool the P3 for 10 - 30 min. depending on the environment and then place the quad an a completely level surface and perform an IMU calibration, and then compass and gimbal calibration, etc.

DO NOT cool the battery !! Props off always.

This might work for you.

Good luck.

:harry

Why do you say to not cool the battery?

I'm in a situation where I need to recharge the battery as fast as possible. I know there is supposed to be a cool down period after flying before charging. I've considered putting the battery in the fridge to speed up the cooling process.

But you say don't? Why?