Scary Waterfall Movie in Brazil - MA almost crashed

[willswing77]

Hi everybody
I am a new MA pilot since May this year and made my experiences in the last couple of months with my Mavic Air. I live in Switzerland and brought my MA to Brazil last summer, where I flew it in many locations. Brought back some nice footage. But my fingers are still trembling when I think back to that waterfall >350 meters tall called "cachoeira do fumaça" in the Chapada Diamantina mountain range. Beautiful spot, but somehow scary to fly. Whatch the movie and you know what I mean. I flew into the wide open space from top of the fall and tried to film it from the front. My MA suddenly decided to keep flying right into the waterfall without any chances for me to control it. The drone was less than 150 meters (50 ft.) away but flew below the starting spot.
I tried to stop it and fly backwards and up, but no reaction from the MA. Fortunately, before drowning and crashing, the forward vision system prevented the loss of my drone.
To learn: can somebody tell me what happened and what could have been the problem? Thanks for investigating on this.

 

[Danr-62]

To my untrained eye looking over the flight record it appears it was doing exactly what you wanted it to do and when you wanted it to do it.

Rocked around by the air little bit there in front of the fall yea but you had full control of it start to finish during that episode. It was reacting to your stick inputs doing as directed.

Looks like it was perhaps a little BVLOS while directly in front of the water fall? come up fast on ya?

That said wait until couple of the others has had a look!

 

[AMann]

Fun video, it would be awesome and nerve wrecking to watch with goggles!

Without looking at the answer on the file, my guess is you lost GPS and it continued drifting forward in ATTI mode even though you tried to stop.

 

[willswing77]

It was reacting to your stick inputs doing as directed.

When I look at my flightlog with PhantomHelp Logviewer I can see that from 1m49s I tried to stop it and move up. But no reaction from the aircraft. That's why it flew right into the fall.
Yes, I couldn't see the aircraft anymore, but that was due to the green surroundings and low contrast.
Loss of GPS was not the case: Log says that there were 18+ satellites all the time.

 

[Danr-62]

When I look at my flightlog with PhantomHelp Logviewer I can see that from 1m49s I tried to stop it and move up. But no reaction from the aircraft. That's why it flew right into the fall.
Yes, I couldn't see the aircraft anymore, but that was due to the green surroundings and low contrast.
Loss of GPS was not the case: Log says that there were 18+ satellites all the time.

You started to climb at 1m 41.8s from -130 feet ending at 1m 49.3s at -92.5 rising 37.5 feet, each command given it reacted to. I didn't see one event it ignored, drifted around a little bit yea but did as you directed it to do.

Not sure what you have braking sensitivity set to in DJI go but the event in front of the falls equals other similar characteristics during that same flight. Speed = distance/time required to a full stop.

Example, (flying backwards) right stick "all the way back" ending at 1m 9.5s moving @ 19mph, = 5.5 seconds to come to a full stop at 1m 15s, traveling several odd feet (I didn't do the math).

Mirroring that aspect of the flight over in front of the falls.
(flying forward) right stick "forward" ending at 1m 48.3s moving @ 17.7mph, = 5.6 seconds to come to a full stop at 1m 53.9s, again traveling several odd feet in those short few seconds.

Wind speed and direction would easily account for the small differences speed = distance to stop those two instances, I didn't check.

 

[Danr-62]

Another observation I wanted to include in my previous post. I did find it odd that you didn't immediately attempt to back away when, reverse course, backing away as it ran up on the water fall much closer than you wanted/expected.

But looking at the flight record perhaps you did try but in that moment of what was surely some level of panic stricken reaction? you hit "left stick" back (throttle), instead of "right stick" full back (elevator) resulting in loss of altitude instead of distance it needed from the water instead?

 

[willswing77]

Thanks for having this close look at my flight log. Yes, it is possible that I mixed the sticks in a sort of panic reaction. I also might have miscalculated the time the drone needed to stop when releasing the forward stick.
Flying near or over water needs special attention and more experience. This is what I learn from this.