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Mavic Air 2, crashed in water. Flight records here

Trying to get DJI to look at it. I know what happened with the battery, but don't know why it went to active track. Tried online chat but aftersales service never available. Thanks all for taking a look.
 
You made several mistakes during this flight & the lack of knowledge over how your craft works made you panic ... you could easily have saved your MA2 but you let it descend into the water unfortunately. All this should be classified as a pilot error nothing else.

-You drained your battery way to far, deliberately canceled the Low battery RTH prompt

-You didn't know anything about the Low battery forced auto landing, when it should kick in or how to stay airborne once activated.

-You was in a semi automated flight mode (Active track) which here & there had some influence over the horizontal speed of your craft, and this would have been clearly indicated on your screen ... you could have easily got out of that by just flipping the mode switch back & forth.

-Once the Low battery forced auto landing was active you panicked ... applied all sorts of stick inputs besides the correct ones. You should have aimed your craft towards closest solid ground, applied forward speed in that direction ... & during this applied throttle for ascent to stop the auto descent.

This shows the erratic & panicked flight path you commanded your MA2 to take ... red X indicate start of Low battery forced auto landing & crash into the water ...

View attachment 142544

You had 3 shorter moment of Active track in the beginning of the flight ... & one long instance starting at 1078sec into the flight which was auto cancelled when the auto landing started.

Checking off how well your stick commands actually worked in the charts below ...

Starting with the Elevator stick (right stick, forward/backward):

The slightly grayer light blue background color to the left = GPS mode with APAS active
The lighter blue background = Low battery forced auto landing active
The red graph = Height above your HP
The green graph = Heading speed
The dashed blue graph = your elevator stick command (right stick, forward/backward, value 1024 is stick neutral)

It's seen in several places before the Low battery auto landing kick in that this movement is somewhat restrained ... this due to you being in Active track mode.

In the logs message stream we find this that could have been the reason ...

View attachment 142546
(Elevator stick vs. heading speed ... click on the chart to make it larger)
View attachment 142545

In the rudder commands we see nothing odd ... the craft responds well & accurate.

Red graph = Height again
Green graph = Adding & subtracting yaw angle
Dashed Blue graph = Rudder stick command (left stick, left/right, value 1024 is stick neutral)

(Rudder stick vs. yaw angle change ... click on the chart to make it larger)
View attachment 142547

When it comes to the throttle inputs they respond as usual before the Low battery auto landing ... when the landing is active the craft will descend with neutral stick ... but slowly ascend with stick at max for ascend. It's easy to see that this you didn't know, when you do the right thing your craft gains altitude ... but you mostly didn't apply enough throttle for ascend so your craft mostly drop it's height & eventually hit the water.

Red graph = Height
Green graph = vertical speed where negative values is ascend & positive is descend
Dashed blue graph = Throttle stick command (left stick, forward/backwards, value 1024 is stick neutral)

(Throttle stick vs. vertical speed ... click on the chart to make it larger)
View attachment 142548

Here below the sad facts about your battery management ...

Red graph = height
Green graph = Battery percentage
Blue graph = Low battery RTH threshold in percent which is distance from HP dependent
Purple graph = Low battery RTH countdown seen on your app screen
Black graph = Low battery forced auto landing threshold in percent which is height dependent

(Click on the chart to make it larger)
View attachment 142549
Thanks so much for taking the time to evaluate. In the horizontal distance stream, (highlighted in yellow above), I don't understand the. "horizontal distance to subject too short". I never manually put it into Active Track.
 
... "horizontal distance to subject too short". I never manually put it into Active Track.
The log doesn't reveal why or how a flight mode was initiated ... but it's no doubt that it was in active track mode, the log is clear about that. You had 3 very short instances of active track mode in the beginning of the flight & one longer which lasted until the low battery forced auto landing started.

The active track mode might have confused you ... but it wasn't the reason that you lost your drone, you had it flying to long & didn't handle the auto landing in a correct way.

When the MA2 autolands, is the downward sensor still on, to avoid hitting anything below it? Looking to learn as much as I can from this incident, and safety is priority.
If your battery is empty no sensor in the world will keep it flying ... this security feature with low battery forced auto landing is height dependent, it will start at a charge percentage that see to that the drone can reach solid ground before the battery is totally dead ... all this to prevent a "dead in the air free fall" situation.

Never mind.... guess its not a "real picture" with the red X. Never had one go down before, so all new to me.
That's correct ... it's a screenshot from a 3D view from Google Earth with your flight path overlayed
 
Happens to the best of us . Use this as a learning tool and get back flying with your care refresh replacement. Don't leave this dampen your ambition
 
When the MA2 autolands, is the downward sensor still on, to avoid hitting anything below it? Looking to learn as much as I can from this incident, and safety is priority.
I think it would be on but it is not an anti collision sensor. It's more a height sensor and suitability or the landing site sensor. Presumably the suitability bit is ultimately over ridden at some point as the battery is drained.
But...... water can confuse the sensor, for future reference low flights over water can be risky and you need to be ready to throttle up if you see it start to descend.
 
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I have read many post with drones ending up in the water. There are also many reason why it happens. Some on this forum will tell you they never had any problems but for me I will not take a chance and will install the float. I would rather have the security plus the option to land on if I want or have to.
IMG_0030.JPG
 
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Sorry to hear about this. Hope you are able to retrieve it and get the DJI Refresh to kick in. Admirable what you were doing, and indeed watch out for the gators.
 
Post #28 is the answer to “panic” over water. Works great with Care Refresh too 😁
My Rescue Jacket is my over water friend.
 
beeflyin said:

When the MA2 autolands, is the downward sensor still on, to avoid hitting anything below it? Looking to learn as much as I can from this incident, and safety is priority.
I think it would be on but it is not an anti collision sensor. It's more a height sensor and suitability or the landing site sensor. Presumably the suitability bit is ultimately over ridden at some point as the battery is drained.
But...... water can confuse the sensor, for future reference low flights over water can be risky and you need to be ready to throttle up if you see it start to descend.
The MA2 downward sensors ARE anti-collision. The MA2 will move around to avoid things it thinks are obstacles. It makes landing on my table top landing zone pretty interesting when the winds are not reasonably still. If not perfectly centered as the drone descends the drone will see the table edge and dart off to avoid it.
 
Interesting do you see the same behaviour with obstacle avoidance switched off? I ask because the downward looking sensors should still be active. What avoidance mode is the drone in? I believe there are 2, brake or bypass, if bypass what happens if the mode is switched to brake?
The 1.6 manual does say, which is the only reference I can find to downward looking obstacle avoidance
"
Obstacle Avoidance During RTH
.................
When aircraft is flying forward:
..............
3. The aircraft brakes when an obstacle is sensed from below and ascends until no obstacle is sensed before flying forward. "
 
I have read many post with drones ending up in the water. There are also many reason why it happens. Some on this forum will tell you they never had any problems but for me I will not take a chance and will install the float. I would rather have the security plus the option to land on if I want or have to.
View attachment 142689
I've considered floats , but what happens if the wind, tide or current take it away from the shore your standing on and out to sea or beyond sight into the middle of a lake ?
 
How many days have you seen a flat-calm. open-sea around the Irish coast, i.e. calm enough that a drone wouldn't be flipped by wave action.
With regards to fighting wind, I have seen a video of a drone being driven across the surface of water but, thinking on it, I am not sure how because they need to tilt to have horizontal thrust. Maybe, on the floats, it didn't sit level but if that was the case you would only be able to drive it in one direction i.e. forwards or backward or sideways, and to change direction you would have to spin it (perfectly feasible).
 
I wonder how fast a drone with floats can fly?
 
I’ve heard the sensors have trouble with water, or most likely all transparent surfaces. I have a similar issue with the lidar sensor on my ipad pro, when I scan over a window it messes up. It needs a solid constant surface Speed Test to measure accurately
 
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