Mavic Pro 2 lost in ocean

[Swamidoc]

I had a recent issue with my Mavic Pro2. It was my 2nd flight of the day, no issues 1st time. I took off again and flew a short distance over ocean, <200 ft from takeoff, 44ft AGA, looked at my phone to line up the shot. The video feed went black, it said disconnected in DJI GO4, and when I looked up, no drone to be seen. Though it was only a couple of feet deep, I could not locate it. DJI was not very helpful, said:

1. The aircraft worked under GPS mode and it responded to the pilot’s commands well;
2. Flight Time T=00:20, Relative Height H=13.5 m, Distance to Home Point D=56.9 m, the pilot pulled back the pitch stick, the flight record ended when the aircraft was flying backward at the speed of 11.3 m/s;
3. The take-off point: 33.0173452 -117.2830520; The last recorded point: 33.0170925 -117.2835829.

The record ended without any sign of abnormality, so we could not verify what happened afterward."

I had a prior drop out of the sky issue with a previous Mavic Pro2. Flying across a 70 degree cliff, back to my takeoff. The drone tilted and fell out of the air. Same basic response from DJI "Based on the currently available data, the root cause of the incident could not be verified". It was thick jungle on Kauai, no way to spot or retrieve the drone!

I have uploaded the flight record and DAT file from the recent crash.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

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Any further insights? This is making me very nervous about flying where I may not be able to retrieve the drone. Bummer, I like to image my friends surfing!

 

[Rchawks]

Sorry for your loss. Welcome to the forum. Lots of experts here.

 

[itsneedtokno]

You should use a Rescue Jacket from @Phantomrain.org

Drone retrieval made simple. Maybe not in a thick jungle, but it would float if the battery popped out over water. Also, added benefit, prop stop on the water, waiting for the right shot. Another added benefit, it's bigger footprint might be visible in the trees.

You could grab it, pour purified water over it, and leave it for days... It would probably be salvageable.

 

[BadWolf1]

I had a recent issue with my Mavic Pro2. It was my 2nd flight of the day, no issues 1st time. I took off again and flew a short distance over ocean, <200 ft from takeoff, 44ft AGA, looked at my phone to line up the shot. The video feed went black, it said disconnected in DJI GO4, and when I looked up, no drone to be seen. Though it was only a couple of feet deep, I could not locate it. DJI was not very helpful, said:

1. The aircraft worked under GPS mode and it responded to the pilot’s commands well;
2. Flight Time T=00:20, Relative Height H=13.5 m, Distance to Home Point D=56.9 m, the pilot pulled back the pitch stick, the flight record ended when the aircraft was flying backward at the speed of 11.3 m/s;
3. The take-off point: 33.0173452 -117.2830520; The last recorded point: 33.0170925 -117.2835829.

The record ended without any sign of abnormality, so we could not verify what happened afterward."

The log and the what DJI say tally (apart from the time of the stick input). Everything was going fine, the aircraft had a little roll one way, flew backwards and adopted a little roll the other way, there's no loss of height no sign of impact, everything just stops. "We count not verify what happened [after the log stopped]" that's no surprise. No descent, no impact, no idea what happened next.

I think the battery came out. 2 reasons for thinking this.
1 The very last data to come back says the speed of all four motors had dropped by ~200-300 RPM in the preceding 0.1 sec. And 2.
15.973 : 1980 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
17.009 : 2032 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.048 : 2084 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.055 : 2084 [L-VISION][VIO]receive vio data befor current ts||
18.184 : 2091 [L-FMU/LED]action changed. sys error:bat_absent(27)
19.320 : 2148 [L-VISION][VIO]receive vio data befor current ts||
19.326 : 2148 [L-NS][AHRS] Bad sample tick measure or recapture signal: 0.010000
20.077 : {task_e}INFO:i2c3 core recovery||
<snip>
20.303 : 2197 [L-BATTERY][ERROR] smbus_read CMD_PRESENT_STATE error||
20.379 : 2201 [L-FMU/LED]action changed. Normal Flash:bat_absent(27)
20.379 : 2201 [L-FMU/LED]type:0, normal flash action:

I think it lost monitoring of the battery and then lost power. I can't prove that. But it reads like it's not seeing a battery.

 

[itsneedtokno]

The log and the what DJI say tally (apart from the time of the stick input). Everything was going fine, the aircraft had a little roll one way, flew backwards and adopted a little roll the other way, there's no loss of height no sign of impact, everything just stops. "We count not verify what happened [after the log stopped]" that's no surprise. No descent, no impact, no idea what happened next.

I think the battery came out. 2 reasons for thinking this.
1 The very last data to come back says the speed of all four motors had dropped by ~200-300 RPM in the preceding 0.1 sec. And 2.
15.973 : 1980 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
17.009 : 2032 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.048 : 2084 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.055 : 2084 [L-VISION][VIO]receive vio data befor current ts||
18.184 : 2091 [L-FMU/LED]action changed. sys error:bat_absent(27)
19.320 : 2148 [L-VISION][VIO]receive vio data befor current ts||
19.326 : 2148 [L-NS][AHRS] Bad sample tick measure or recapture signal: 0.010000
20.077 : {task_e}INFO:i2c3 core recovery||
<snip>
20.303 : 2197 [L-BATTERY][ERROR] smbus_read CMD_PRESENT_STATE error||
20.379 : 2201 [L-FMU/LED]action changed. Normal Flash:bat_absent(27)
20.379 : 2201 [L-FMU/LED]type:0, normal flash action:

I think it lost monitoring of the battery and then lost power. I can't prove that. But it reads like it's not seeing a battery.

That's why I suggested the Rescue Jacket, because M2 bats are known to pop out. ?



And I agree, that's what appears to have occurred

 

[Swamidoc]

The log and the what DJI say tally (apart from the time of the stick input). Everything was going fine, the aircraft had a little roll one way, flew backwards and adopted a little roll the other way, there's no loss of height no sign of impact, everything just stops. "We count not verify what happened [after the log stopped]" that's no surprise. No descent, no impact, no idea what happened next.

I think the battery came out. 2 reasons for thinking this.
1 The very last data to come back says the speed of all four motors had dropped by ~200-300 RPM in the preceding 0.1 sec. And 2.
15.973 : 1980 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
17.009 : 2032 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.048 : 2084 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.055 : 2084 [L-VISION][VIO]receive vio data befor current ts||
18.184 : 2091 [L-FMU/LED]action changed. sys error:bat_absent(27)
19.320 : 2148 [L-VISION][VIO]receive vio data befor current ts||
19.326 : 2148 [L-NS][AHRS] Bad sample tick measure or recapture signal: 0.010000
20.077 : {task_e}INFO:i2c3 core recovery||
<snip>
20.303 : 2197 [L-BATTERY][ERROR] smbus_read CMD_PRESENT_STATE error||
20.379 : 2201 [L-FMU/LED]action changed. Normal Flash:bat_absent(27)
20.379 : 2201 [L-FMU/LED]type:0, normal flash action:

I think it lost monitoring of the battery and then lost power. I can't prove that. But it reads like it's not seeing a battery.

that seems reasonable. I have a new one on order from DJI, 50% discount. an expensive lesson. Battery secure is already part of my pre-flight check. perhaps a velcro strap (belt and suspenders).

 

[Radpuppy]

that seems reasonable. I have a new one on order from DJI, 50% discount. an expensive lesson. Battery secure is already part of my pre-flight check. perhaps a velcro strap (belt and suspenders).

I’m thinking on a Velcro safety strap to put on my M2p after reading this

 

[itsneedtokno]

I’m thinking on a Velcro safety strap to put on my M2p after reading this

Not a bad idea.

Maybe a getterback or two, or the set up I mentioned.

It's called the "Sea Lander" for the Mavic 2, not a Rescue Jacket, that is the MA2 version.

 

[sar104]

The log and the what DJI say tally (apart from the time of the stick input). Everything was going fine, the aircraft had a little roll one way, flew backwards and adopted a little roll the other way, there's no loss of height no sign of impact, everything just stops. "We count not verify what happened [after the log stopped]" that's no surprise. No descent, no impact, no idea what happened next.

I think the battery came out. 2 reasons for thinking this.
1 The very last data to come back says the speed of all four motors had dropped by ~200-300 RPM in the preceding 0.1 sec. And 2.
15.973 : 1980 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
17.009 : 2032 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.048 : 2084 [L-BATTERY][ERROR] BATTERY_STATE_ABSENT||
18.055 : 2084 [L-VISION][VIO]receive vio data befor current ts||
18.184 : 2091 [L-FMU/LED]action changed. sys error:bat_absent(27)
19.320 : 2148 [L-VISION][VIO]receive vio data befor current ts||
19.326 : 2148 [L-NS][AHRS] Bad sample tick measure or recapture signal: 0.010000
20.077 : {task_e}INFO:i2c3 core recovery||
<snip>
20.303 : 2197 [L-BATTERY][ERROR] smbus_read CMD_PRESENT_STATE error||
20.379 : 2201 [L-FMU/LED]action changed. Normal Flash:bat_absent(27)
20.379 : 2201 [L-FMU/LED]type:0, normal flash action:

I think it lost monitoring of the battery and then lost power. I can't prove that. But it reads like it's not seeing a battery.

That's a very likely explanation. The BATTERY_STATE_ABSENT flag means that the battery clip switches are reading open.

 

[Ralph thompson]

I believe (simply my opinion) that the battery will securely lock in place if you install it carefully. I have had almost 2 years & a lot of use out of my M2P. My checklist states “instal battery, 2 hands, check secure” I glance at the buttons to see if they look normally extended. I had a battery disconnect on my Inspire, fortunately it was only an inch off the ground, the problem was dirty connectors. They were easy to clean but not sure how to clean M2P terminals.

 

[sar104]

I believe (simply my opinion) that the battery will securely lock in place if you install it carefully. I have had almost 2 years & a lot of use out of my M2P. My checklist states “instal battery, 2 hands, check secure” I glance at the buttons to see if they look normally extended. I had a battery disconnect on my Inspire, fortunately it was only an inch off the ground, the problem was dirty connectors. They were easy to clean but not sure how to clean M2P terminals.

It will lock properly with your procedure provided that the battery is not swollen, but it's clear that not everyone does those checks. Additionally, if the battery swells during flight, it appears that it can pop the clips open even if they were closed properly at the start of the flight.

 

[Reelman67]

Okay, now I am aware that my M2P could fail at any time. Glad I have State Farm insurance. Thank you Sar104 for your insightful comment.

 

[peterc4]

Had the exactly the same in April and the same responce mate, 2 pros are very good at disconnecting and falling out of the skyDJI need to step up and admit there is a problem..

 

[johnmoxl]

Okay, now I am aware that my M2P could fail at any time. Glad I have State Farm insurance. Thank you Sar104 for your insightful comment.

Yes I bought similar insurance with Progressive. Not needed it yet.

 

[Swamidoc]

It will lock properly with your procedure provided that the battery is not swollen, but it's clear that not everyone does those checks. Additionally, if the battery swells during flight, it appears that it can pop the clips open even if they were closed properly at the start of the flight.

My batteries look OK. How can I check that?

what would make the battery swell during flight?

 

[Swamidoc]

Yes I bought similar insurance with Progressive. Not needed it yet.

Is this with your homeowners insurance?

 

[sar104]

My batteries look OK. How can I check that?

Check what?

what would make the battery swell during flight?

High discharge rates and overheating causing the formation of metallic lithium and free oxygen. It shouldn't happen to new batteries running within spec, but older and/or thermally damaged batteries may succumb at lower discharge rates.

 

[johnmoxl]

Is this with your homeowners insurance?

That’s right, I think it was add’l $28/6 mos

 

[Swamidoc]

That’s right, I think it was add’l $28/6 mos

With what deductible? Mine is so high it wouldn’t pay to file a claim!

 

[Reelman67]

Is this with your homeowners insurance?

My State Farm policy (personal articles policy) is strictly for the drone coverage (loss only). I have no other coverage for either home or car with them. No deductible. $75 per year at the moment. That's their minimum rate for a PAP policy.