Searching for an Air today . . .

[MAvic_South_Oz]

Wish me luck !!
After a long absence from flying my MP (long story, away from it for another week), I went for a fly late yesterday with my Spark, along with my Brother in law and his Mavic Air.
He's had it for a couple of months after his first Spark, and with just 35km on the odometer put it into a cliff face on a rocky beach, doh !

We have a very good location on find my drone, which matches his flight log and video feed of it going sideways into a cliff face some 12m up, a bit of a tumble down.
I'm going there solo this morning in a couple of hours for a quick look from below, put the Spark up if needed to have a little search up high.

Although I have climbing / abseiling experience and basic harness, helmet etc, I have no ropes or climbing rock hardware so won't be doing anything stupid . . . yeah, that's what I ALWAYS say !!!
No seriously, not doing it, steepest part of the cliff he could have hit, suspect it will be at the base, but high tide is in half an hour so will have to see if I can access cliff base there.

I'll try and get his logs and upload later, would like to know why this happened and the way it went sideways into the cliff with only yaw input apparently.

Edit - postponed a couple of hours, after checking tides. It's just come off high tide, darn it. At least the lower of the 2 high tides today, and no wind last night / this morning, so should be ok to access mid morning South Oz time.

 

[MAvic_South_Oz]

The cached video . . .

 

[Thomas B]

Ouch!
Best of luck!

 

[MAvic_South_Oz]

Just home a while ago, I found it ok, had tumbled the 12m (40' or so) down the cliff face, maybe bounced off the rocks below and into the high tide zone, or it landed at the foot of the cliff and was taken out by several metres (10' or so) by waves.
The body got some wave action marks for sure ?, not all caused by the crash ?

One arm snapped near the motor.

I've taken the battery off (was secure), micro SD card out, props off, filter off, and washed all those with fresh water.
Also just gave the bird a dunk with fresh water and shake out (with BILs permission), can't hurt, this has been immersed in salt water, and was actually still sitting 3/4 in a rock pool of water from the high tide.
In the sun drying a bit after shaking all different ways to get bulk or water out (salt water shaken out similarly after picking it up so it got through it pretty well).

Brother in Law is aware of the situ, he'd going to try a stocking with a few cups of rice, into a sealed plastic container, and see it will live again.

I think it's toast, but didn't have the heart to tell him until he finishes work and comes up later.
If it were mine, I couldn't trust it again, I'm sure circuits / wiring etc would be affected by corrosion in short term, if it were to run again.
It needs parts anyway.

The battery too would likely be fried ?
Pretty sure not waterproof enough to survive that without possible corrosion in short term (or it's just fried from water contact).

Will post up some pics from the phone in a minute.

I'd also like to post the flight files for someone to look over.

It definitely went sideways into the cliff, BIL says he was only yawing, but maybe he was operating the roll stick . . .
If he is right about him only yawing, it could be that weird compass 180 degree thing, although I did tell him to always check that before taking off.

 

[MAvic_South_Oz]

Pics . . .

The crash site way up high . . .


Fell down . . .


and down . . .


Somehow got out here (see it ? It's a red MA, just right of centre) . . .


And here it is in it's little swimming spot . . .


So toast ? (finished, kaput, DOA, RIP ?)

Will try and get flight info form BILs logs tonight, or may be another 24 hours.

 

[Thomas B]

Best of luck.
I fear, as you surmise, it’s likely toast though.

 

[Grumpy D]

Likely that the salt water has already done to much damage. I suggest you skip the rice and submerge in 91% Isopropyl Alcohol swish it around and shake out excess and let it set and allow the alcohol evaporate. I’ve had good luck with this method, but it was fresh water.

 

[MAvic_South_Oz]

Likely that the salt water has already done to much damage. I suggest you skip the rice and submerge in 91% Isopropyl Alcohol swish it around and shake out excess and let it set and allow the alcohol evaporate. I’ve had good luck with this method, but it was fresh water.

Yeah I think last night when he saw it he knew it was all over.
Really about all salvageable is the filter !!

He was still going to soak long in distilled water, didn't know about the isopropyl method, will have to have a google and read up.
I use quite a bit of iso in one of my work fields, buy it by the 5lt (a bit over a gallon) so have it on hand.

He's dropped his ipad off tonight and I'll have a crack at getting the flight files off to post up.

 

[MAvic_South_Oz]

Ok, here are the text and dat files from that flight.

DJI Flight Log Viewer - PhantomHelp.com

Seems to slow to almost nil about 5m 40s, rear obstacle avoidance ?
About 5m 54s he starts roll left, rather than yaw.
Then introduces left yaw, continues to 6m 4s when he let go of the sticks.
I think it may have hit at 6m 4.3s VPS cuts in, seems to go all over the place ???

Dat attached too.

I will have a look at the DJI log viewer too, very interesting . . . but would REALLY appreciate some expert advice as to what may have happened here.
My Brother in Law is working out the best way to get another Air, but I said hang off a bit to see what comes back from some analysis.

Edit - I looked over the flight log and map, would I be right he basically flew it into the cliff ??
That's what it looks like to me, but I don't know how to do the magic with the dat file, if that sheds any more light on it.

Thanks in advance.

 

[sar104]

The aircraft responded normally to all inputs - he flew it backwards and sideways into a cliff. There's not much more to say.

 

[MAvic_South_Oz]

Pretty much, thanks.

 

[adam3112]

I thought the air had obstacle avoidance on the sides and rear?

 

[MAvic_South_Oz]

I thought the air had obstacle avoidance on the sides and rear?

That's the sort of thing I was interested in in analysis.
But the Air doesn't have the side sensors, only the front, bottom and rear sensors.

(The M2P has side sensors, but they only work in tripod and active track modes !!)

I was keen to see if any data showed the rear sensor stopping Peter backing into the cliff, it looks like it does on the DJI log viewer, seems to be still stick back, but speed redused to very minor drifting I think, 1 to 2mph etc.

Suppose more detailed interesting points about that part of the flight aren't worth going past the simple fact of pilot error 100%, even I saw his sticks taking him curving into the crash.

I don't think he realised he was using roll and / or yaw when he did, seems to have a lot of stick movement to gain altitude when it seems he first backed up to the cliff with right stick full back, and stopped with to almost no speed.
For some reason full up wasn't responded to, it just sat at 354'.
Then the slow drift to the south with left roll, then later introduced a slight left yaw, which sealed its fate as the rear sensors lost effectiveness in the turn.
The horizon display on he viewer shows impact I think at 6m 4.4s.

Anyway, I learned that part of the logs is reasonably easy to check lots of factors, not sure but dat files might be the ones with much more detailed info to correlate to that to make the graphs these blokes use for their sometimes incredible analysis.

 

[irpnetgb]

FWIW - whatever action you do with the MA, do not power it on for a week or more. Give it plenty of time to dry out. The longer the better. You may get corrosion on the board(s) but you could possibly mitigate that by taking it apart and using something like WD40 to inhibit any water penetration and then leave it to dry.

 

[MAvic_South_Oz]

FWIW - whatever action you do with the MA, do not power it on for a week or more. Give it plenty of time to dry out. The longer the better. You may get corrosion on the board(s) but you could possibly mitigate that by taking it apart and using something like WD40 to inhibit any water penetration and then leave it to dry.

Thanks mate, the brother in law has the Air in a sealed bucket now, in a stocking wrap, with about a kg of rice to help dry it out.
He's not going to fly it again though.
May get it fixed but really it's only the mainframe that is usable, everything else is needed new . . . he will likely be better to just get a new Air and battery if possible and be done with it I think.
About a grand either way, so I think the new bird is best.