Help: Drowned Mavic Pro

[tony_hetherington]

I read recently that, when flying over water, it's best to disable the lower sensors; is that correct? (I have a Mavic Air, if that matters)?
Thanks!

 

[BudWalker]

That's exactly correct, with one additional factor that in my opinion may be a firmware problem:

View attachment 69878

The aircraft did not actually backflip as described by the OP, but it reached 76° pitch in braking, followed by motor shutdown:

View attachment 69879

That's confirmed in the event stream:

1156.864 : 62593 [L-FDI][CTRL]: fault on , tilt_ctrl_fail​

1156.880 : 62594 [L-FMU/MOTOR] Stop. reason:roll over or atti fail​

1156.882 : 62594 [L-FMU/MOTOR]Total start times: 1, time:1156.88​

1156.882 : 62594 [L-PWM]set actuator mode:IDLE​

1156.882 : 62594 [L-FLYMODE]CTRL reset all by motor stopped​

1156.882 : 62594 [L-RC]craft ctrl failed!!!​

1156.883 : 62594 [L-FMU/FSM]state changed. cur: motor off​

1156.884 : 62594 [L-FDI][CTRL]: fault off, tilt_ctrl_fail​

1156.899 : 62595 [L-IMU]set imu switch level = 1​

1157.062 : 62603 [L-RC]Emergency break. rc vib!​

1157.199 : 62610 [L-FDI]NS(0) GPS(0): fault on , abrupt​

Unless the parameters on this aircraft have been modified, allowing 76° of pitch during braking, the firmware should not shut down the motors in flight as a result.

On the plus side is that the motor stop on detecting excessive tilt worked correctly.

 

[sar104]

I read recently that, when flying over water, it's best to disable the lower sensors; is that correct? (I have a Mavic Air, if that matters)?
Thanks!

Height sensing can be a problem close to the surface. This is the first case I've seen that led to emergency braking. But that, itself, was not an issue - the aircraft would probably have been fine if the FC hadn't kill the motors due to the pitch excursion.

 

[BudWalker]

I read recently that, when flying over water, it's best to disable the lower sensors; is that correct? (I have a Mavic Air, if that matters)?
Thanks!

That's probably a good idea. But, in this case if the obstacle avoidance system were turned off the incident would have been avoided.

 

[sar104]

On the plus side is that the motor stop on detecting excessive tilt worked correctly.

Except it shouldn't do that at all. This was a clear example where the aircraft would have recovered - in fact it had before the motors stopped. This frame is just before it hit the water, after the pitch excursion had been corrected:

 

[tony_hetherington]

That's probably a good idea. But, in this case if the obstacle avoidance system were turned off the incident would have been avoided.

Ah I see - obstacle avoidance as in APAS? Ok cool thanks I'll do that too.

 

[glanrock]

Extremely impressive the way folks here dig through the logs.

I'd read early that flying near the water was "iffy" because the drone may get confused about the surface. I fly above the water a lot, but I am too nervous to fly close to it.

Feel bad for the OP to lose the drone in that manner, that's a huge bummer.

 

[Joe4flight]

Logs are easy to read. A monkey can do it, just sit down and learn to read it once and it becomes second nature. Good skill to have to analyze crashes. I wish it would have more info like exact coordinates on the hardest impact. Or maybe even a selfie shot of the operator when it crashed. Hehe. Last one is a joke.

Hello Trollistika, Monkeys are pretty intelligent creatures. I look at a flight log and it all looks like a foreign language to me. What is the best way to learn how to interpret flight logs? I’m all ears!! Yes, seeing a selfie of the pilot when their drone crashes would be amazing. Thx!!

 

[BudWalker]

Except it shouldn't do that at all. This was a clear example where the aircraft would have recovered - in fact it had before the motors stopped. This frame is just before it hit the water, after the pitch excursion had been corrected:

View attachment 69887

Just kidding.

 

[Deleted member 94047]

These crash autopsies you guys do never cease to amaze me.

 

[sar104]

Just kidding.

Yes - I realized that after I replied. But it is an interesting case in the light of all the discussions about motor shutdown. We've seen numerous cases of tumbling due to prop loss without this happening, and this is the first case I've seen where the FC definitively shut down the motors even as the aircraft was recovering from the excursion. So clearly I was wrong in saying that it won't happen, but it hasn't generally happened, so I'm wondering what is going on.

I'd also add that the OP would have a very good case for a replacement if this were in warranty, but unfortunately it's 2½ years old.

 

[ehougaard]

Thanks for sharing. Did you have the sensors turned off when flying over water? I always turn Them off when flying over water but have not flown so close as you did, cojobt. But turned off Are there still a risk loosing control close to water or should it be eliminated then?
Thanks

 

[MavicMikeK]

And just found out my household insurance doesn't cover drones, even though I have Miscellaneous Personal Items cover, so my phone, cameras, laptop, and even music production gear are covered, but not drones, even though my drone lives beside my camera in the boot of the car most of the time, and is considered equally valid as 'personal effects' to my mind. Drones are obviously too high-risk and aren't covered at all.

I recently purchased drone insurance from State Farm for $60/yr and it covers any loss whatsoever with zero deductible. They took pics of my new Mavic Pro Platinum, copies of my receipt and I'm fully covered. You might want to look into it. I've also had State Farm as my home & car insurance for over 20 years, they're a great company.

 

[WAXMAN]

Never doubt yourself my dude!

I doubt myself all the time! It happens as you get older.lol

 

[Sowsalbitters]

Someone had mentioned something about State Farm earlier. Is Drone insurance part of your home owners policy or do they offer Drone insurance

 

[brett8883]

I have to ask, and you can be honest with me, is this my destiny? As a new drone owner, am I going to crash my drone into a lake or ocean? Do they always flip or spiral out of control? I bought a Mavic Air. It’s my very first drone. How often do these things fly away even with GPS and RTH properly set?

Not to beat up the OP while they are already down but flying 2 feet over water was il advised and they had to know it was a real risky

Someone had mentioned something about State Farm earlier. Is Drone insurance part of your home owners policy or do they offer Drone insurance

This happened in the U.K. I believe.

 

[dawgpilot]

Someone had mentioned something about State Farm earlier. Is Drone insurance part of your home owners policy or do they offer Drone insurance

It's considered a separate Personal Articles policy that State Farm offers.

 

[Bigbird48]

I've been in sports mode full out and hit the pause button. The drone goes almost vertical when I do this and the motors have never stopped. Just did this a couple times cause guys here said it was cool effect and it is but a couple time is enough LOL ?

 

[Sowsalbitters]

thank you for the info. I will look into this.

 

[sar104]

I've been in sports mode full out and hit the pause button. The drone goes almost vertical when I do this and the motors have never stopped. Just did this a couple times cause guys here said it was cool effect and it is but a couple time is enough LOL ?

That's how I would expect it to behave - it makes no sense at all for the FC to stop the motors in this situation.