Why did it fly away?

[JTS]

Agreed, that's the same issue: GPS suddenly turned off even though there are plenty of sats available. It's as if the sensor data isn't reliably making it through to the FC, although it's being logged (presumably by a different processor). Maybe an I2C problem. Anyway, IMHO I'm afraid it's a hardware fault.

I'll be adding a routine to my analysis software to check for this condition.

 

[JTS]

Just noticed the town next to this flight is called "Launching Place". Perhaps the Mavic just got confused

 

[Drekker]

Just noticed the town next to this flight is called "Launching Place". Perhaps the Mavic just got confused

Very funny

 

[Drekker]

Agreed, that's the same issue: GPS suddenly turned off even though there are plenty of sats available. It's as if the sensor data isn't reliably making it through to the FC, although it's being logged (presumably by a different processor). Maybe an I2C problem. Anyway, IMHO I'm afraid it's a hardware fault.

I'll be adding a routine to my analysis software to check for this condition.

Thanks for the help everyone. Glad there was some consensus on what happened. Still not sure why the controller dropped out, but there looks to be no good reason the Mavic didn't know where it was.

 

[msinger]

Still not sure why the controller dropped out

It looks like there were a lot of trees between the remote controller and Mavic. If that was the case, it would have blocked the signal.

 

[Drekker]

It looks like there were a lot of trees between the remote controller and Mavic. If that was the case, it would have blocked the signal.

After fly off there were trees between. When the control dropped out, my estimate is it was in clear air, straight up.

 

[Drekker]

After fly off there were trees between. When the control dropped out, my estimate is it was in clear air, straight up.

Maybe it drifted a long way and found some obstruction that I didn't notice.

 

[msinger]

After fly off there were trees between. When the control dropped out, my estimate is it was in clear air, straight up.

Your Mavic was about 150 feet in the air when the downlink disconnected. Considering how far away it was at that time, I don't think the line of sight was as clear as you're recalling.

 

[Drekker]

Your Mavic was about 150 feet in the air when the downlink disconnected. Considering how far away it was at that time, I don't think the line of sight was as clear as you're recalling.

Could be. I think this drone wanders. Once it couldn't understand its satellite data any more, It just drifted away and lost contact.

It does have a problem flying straight as well. I will work on that as a separate issue (everything recalibrated except the controller due to the software not working).

For now, it is going back to DJI.

 

[msinger]

Once it couldn't understand its satellite data any more, It just drifted away and lost contact.

Yes -- that's how the Mavic is supposed to fly when in ATTI mode.

 

[BudWalker]

@Drekker I looked at this flight. In summary, the root cause is the gpsHealth dropping to 1 which caused a switch to ATTI mode. After that the behavior was pretty much predictable and as it should be. In particular, it responded normally to control inputs while it had a connection with the RC. If this were my Mavic I wouldn't fly it again until DJI repair had fixed the GPS problem.

There have been several incidents lately (seems like I analyze one every day) caused by the gpsHealth dropping from 5 to 1. gpsHealth needs to be 4 or greater for GPS navigation. gpsHealth probably is a measure of signal strength and is not the same as numSats. In this incident gpsHealth dropped to 1 at about 62 seconds and the Mavic switched to ATTI mode. Until about 1187 the Mavic was drifting with the wind since the only control inputs where throttle and rudder.



Throttle input caused the Mavic to rise at first but then was used to lower the Mavic until it got low enough to loose the RC connection. at about 207 secs. Apparently the Mavic didn't drift much at this lower altitude. RC connection was re-established at about 660 secs.


At 1180 secs control inputs flew it over and landed it where the pilot was.

 

[DirkGently]

Oh great - another return of my Mavic.

What is weird is it did re-gain GPS after 2 minutes 30 in my case and was fine after that - though obviously I kept the Mavic close.

If its a firmware issue then this is something DJI can fix with an update.

But if the GPS itself is faulty then only a return will fix it. But generally with hardware issue they either work or they don't.

I can't fly as weather terrible here for the next 5 days but might do some more tests once it improves. So far its happened just once to me.

 

[zorr0]

I can see the flight logs on the app, but how do I share or find the txt file? Sorry for newbie questions.

Do a screen copy. Hold down home and pwr button simultaneously. Then add jpeg to posting. I’m sure there are easier ways to save log, I’ve just never tried. Screen cap is good for lotta stuff

 

[kakao]

Once it couldn't understand its satellite data any more, It just drifted away and lost contact.

Yes -- that's how the Mavic is supposed to fly when in ATTI mode.

In order to fly in ATTI mode AC needs to have a contact with RC ..

 

[msinger]

In order to fly in ATTI mode AC needs to have a contact with RC ..

That's certainly not accurate. Mavics can fly in P-mode or ATTI-mode while disconnected from the remote controller. They don't just drop from the sky when the remote controller disconnects

 

[kakao]

That's certainly not accurate. Mavics can fly in P-mode or ATTI-mode while disconnected from the remote controller. They don't just drop from the sky when the remote controller disconnects

Sure, a Mavic can fly, but on its own .. which doesn't help a pilot at all.

 

[msinger]

Sure, a Mavic can fly, but on its own .. which doesn't help a pilot at all.

You lost me. Why are you quoting me and then providing incorrect information? Am I missing something important here?

 

[joejaxvic123]

No RTH?

 

[kakao]

You lost me. Why are you quoting me and then providing incorrect information? Am I missing something important here?

You said:
Mavics can fly in P-mode or ATTI-mode while disconnected from the remote controller.

I'm saying:
I thought that in ATTI mode, for one to control the AC, the connection between the RC and AC is the must ..?! How an AC can fly in ATTi mode if disconnected from the RC? Probably on its own, but it can not be controlled by the pilot if there is no connection between the AC and RC ..

Apologies if I was not clear, no offence intended.

 

[ac0j]

It had control, OP didnt use it. Waited till the AC was blown out of range.