Will an Unusual Pitch Attitude (>70deg) Cause the Motors to Shutdown

JAW · Apr 3, 2019

Trying to get the definitive answer for the Mavic 2-----Will a high speed quick-stop which causes the pitch attitude to be very high cause the motors to automatically shut down?

Thanks

sar104 · Apr 3, 2019

JAW said:
Trying to get the definitive answer for the Mavic 2-----Will a high speed quick-stop which causes the pitch attitude to be very high cause the motors to automatically shut down?

Thanks

No. Attitude excursions in flight will not shut down the motors. Why does this keep coming up?

JAW · Apr 3, 2019

sar104 said:
No. Attitude excursions in flight will not shut down the motors. Why does this keep coming up?

Actually, about a year ago in another thread* re: the cause of a crash, you stated:
The motors were shut down by the FC at 99.283 s when the roll exceeded 70°

So is it just roll attitude that can cause a shutdown? Just trying to get some clarification.

*Post #2 Mavic drops out of sky - crashes - why?

sar104 · Apr 3, 2019

JAW said:
Actually, about a year ago in another thread* re: the cause of a crash, you stated:
The motors were shut down by the FC at 99.283 s when the roll exceeded 70°

So is it just roll attitude that can cause a shutdown? Just trying to get some clarification.

*Post #2 Mavic drops out of sky - crashes - why?

Nice detective work - I had completely forgotten that one, or that I had stated that conclusion. Let me take another look at the data from that flight.

BD0G · Apr 3, 2019

We have seen videos of people turning the Mavic Upside Down to shut off the propellers. I personally would not do that , but to each thier own. This must mean that this "feature" is also used upon the Mavic 2 as well.
Once the drone is rolled over past a certain point then the craft does an auto shutoff of the motors.

A little update from DJI about the emergency shut off. It is intended to shut off the motors in a wreck situation.

BD0G · Apr 3, 2019

Whats interesting is that I have done full throttle Sport Mode flyby's and then pressed the Pause button on the Remote Controller to do "tail stands" and have not had the Mavic Pro shut off propellers in mid flight due to roll angle.

I may have just been lucky the 10 + times that I have done that. <shrug>

sar104 · Apr 3, 2019

BD0G said:
Whats interesting is that I have done full throttle Sport Mode flyby's and then pressed the Pause button on the Remote Controller to do "tail stands" and have not had the Mavic Pro shut off propellers in mid flight due to roll angle.

I may have just been lucky the 10 + times that I have done that. <shrug>

No - the incident mentioned above is definitely an outlier. I'd really like to be able to explain it though.

JAW · Apr 3, 2019

I spent some time Googling the auto-shutdown features of Mavic drones and the opinions were all over the place. One person reportedly suffered a finger slice when he picked up his crashed and upside down Mavic 1 whose motors were still running. Then there's a video of a tri-bladed Mavic that the poster was afraid would shutdown after abrupt stops in sport mode. On the DJI forum. a tech said that in-flight maneuvering would not cause motor shutdown while several posters disagreed with him. A posted you tube vid apparently shows a camera view of a Mavic Pro performing a loop that obviously did not cause a shutdown.
The only other drone I have experience with is a Blade product which would definitely shutdown after a crash. But no amount of inflight gymnastics would cause a shutdown.

sar104 · Apr 3, 2019

JAW said:
I spent some time Googling the auto-shutdown features of Mavic drones and the opinions were all over the place. One person reportedly suffered a finger slice when he picked up his crashed and upside down Mavic 1 whose motors were still running. Then there's a video of a tri-bladed Mavic that the poster was afraid would shutdown after abrupt stops in sport mode.

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On the DJI forum. a tech said that in-flight maneuvering would not cause motor shutdown while several posters disagreed with him. A posted you tube vid apparently shows a camera view of a Mavic Pro performing a loop that obviously did not cause a shutdown.

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The only other drone I have experience with is a Blade product which would definitely shutdown after a crash. But no amount of inflight gymnastics would cause a shutdown.

The firmware for the Mavics does shut down the motors (or prevent them from starting) if the aircraft is tilted past 70° or so when not in flight (before takeoff or after landing/crashing). We have many sets of data showing that shutdown doesn't occur even with inverted attitude, as you would expect - that would not be a clever strategy since these flight control systems are designed to recover from such excursions, not give up and plummet to the ground. You can disregard anyone posting that they are worried about it - people worry about all kinds of non-existent problems, but if there are any other documented cases where shutdown did occur due to flight attitude then I'd definitely be interested to see them.

A quick look back at the DAT files from the flight that you mentioned above confirms that the FC reported tilt control failure and motor shutdown due to rollover:

99.464 : 6934 [L-FMU/FSM]not near ground

99.523 : 6937 [L-FDI][CTRL]: fault on , tilt_ctrl_fail

99.540 : 6938 [L-FMU/MOTOR] Stop. reason:roll over or atti fail

Looking at the txt log, which includes the OSD_groundOrSky flag record shows that it (incorrectly) switched from Sky to Ground which, in conjunction with the pitch at that point (~ 85°), is what caused the motor stop command to be issued. In other words the FC, at least briefly, erroneously thought it had landed or crashed. That does not usually happen in flight.