Need Crash Analysis

[John Locke]

I lost my first drone in 6yrs last week, fortunately is was my Mini2, my least cost toy. The craft was lost in a river as I was flying about 6' above it, capturing ducks floating in the river. I was hoping someone in this forum could do an analysis on the flight record to disclose the details of what happened at the very end. I was flying about 400' away with clear VLOS. There were no obstacles in the middle of the river where I was flying. I have flown this area of the river many times so I know it well. However when I was flying, all of a sudden the screen picture jerked erratically then went black. I looked up VLOS and didn't see the craft anymore. It vanished. I looked back at the iPad an I saw "IMU error" message on the screen. I pushed RTH in desperation, but as expected, no joy. When I reviewed the iPad video cache it looks like it went into the green water. The color shown in the last frame on the video was green, showing streaks like a splash. Even though I had a refresh policy, I was denied refresh replacement because I couldn't retrieve return the craft. DJI denied and IMU failure warranty, saying there was no indication of IMU failure in the flight record. I'm unsure how that can be true if I saw the message on the screen. I would think a record of that message would be in the flight record. If someone could analyze this flight record I would appreciate it. Thanks much.

 

[Phantomrain.org]

Sorry to hear this John , not for the loss but the World record I think you held, and now its set in stone .

I am thinking the IMU error was to late in the Process of it going in the water , as I have been flying the Mini 2 a lot this month . The only thing I have noticed is how quick it is to land on the water compared to all the other drones that put up a little bit of a fight with the sticks.

Will keep this on watch, but thinking loss of signal .
sorry about your loss,

Phantomrain.org
Gear to fly your Mini 2 in the Rain.

 

[slup]

...The craft was lost in a river as I was flying about 6' above it
...I saw "IMU error" message on the screen.
...I was denied refresh replacement because I couldn't retrieve return the craft.

If someone could analyze this flight record I would appreciate it. Thanks much.

When the event that made your AC dive into the water started the sonar sensor reported 2,6ft.

No signs is found in the log regarding a IMU error before or after the AC becomes disturbed & dives ... if you recall this correctly, that message most probably was a result of that the AC goes into the water, nothing is in the log though.

You skimmed close over the water at approx. 1.6mph in Tripod mode sideways slowly yawing ... at 481,3sec into the flight the AC suddenly roll into the flying direction & pitching down & rotate CW a quarter turn ... nothing in the log indicate any reasons for the rapid movement just before it went under ... the throttle stick wasn't touched (value 1024 in the chart is neutral) my guess is that you either flew into something that hit the front left arm (a thin branch sticking up from the water) or a bird attacked it. This thru the AC out of balance & it hit the water surface ...

As this is a Mini 2 we don't have access to anything more than this ... the mobile device DAT log including raw sensor & motor data is encrypted & can only be read by DJI, that one could have given us more to go on.

 

[hiflyer201]

Do you think you could have hit a duck? I have many videos where birds have swooped past close from behind the drone.

 

[timinator]

Do you think you could have hit a duck? I have many videos where birds have swooped past close from behind the drone.

That's what I'm thinking. Maybe have a word or two with those ducks

Sorry to hear you lost the bird, John. I don't think they would have feathered up to your P4.

 

[cgmaxed]

I lost my first drone in 6yrs last week, fortunately is was my Mini2, my least cost toy. The craft was lost in a river as I was flying about 6' above it, capturing ducks floating in the river. I was hoping someone in this forum could do an analysis on the flight record to disclose the details of what happened at the very end. I was flying about 400' away with clear VLOS. There were no obstacles in the middle of the river where I was flying. I have flown this area of the river many times so I know it well. However when I was flying, all of a sudden the screen picture jerked erratically then went black. I looked up VLOS and didn't see the craft anymore. It vanished. I looked back at the iPad an I saw "IMU error" message on the screen. I pushed RTH in desperation, but as expected, no joy. When I reviewed the iPad video cache it looks like it went into the green water. The color shown in the last frame on the video was green, showing streaks like a splash. Even though I had a refresh policy, I was denied refresh replacement because I couldn't retrieve return the craft. DJI denied and IMU failure warranty, saying there was no indication of IMU failure in the flight record. I'm unsure how that can be true if I saw the message on the screen. I would think a record of that message would be in the flight record. If someone could analyze this flight record I would appreciate it. Thanks much.

I have gotten an IMU error before. Why? Because my drone crashed into the water. The water can cause an IMU error almost immediately.

 

[Capt KO]

Looks like an easy swim to recover. I always use a rescue float over water to be able to use refresh. Now switched to a Rescue Jacket on my A2. Minis from my experience do not do well when low over water, more so than my others. Bottom sensor gets confused (uncommanded decent) so I rarely fly it less than 20’ over water. Hovering or slow flight makes it worse. Hope you find it. GL

 

[John Locke]

I have gotten an IMU error before. Why? Because my drone crashed into the water. The water can cause an IMU error almost immediately.

That's good to know about your IMU error, thanks for the confirmation of my suspicion. Since there were no objects to run into over the water, I'm 100% sure it was a duck. Right before the loss I saw ducks coming into view as if they swam right under the craft. I think one got spooked and flew straight up 5' and collided with me. I've seen ducks fly straight up like that before. I was really surprised to see the duck coming into view when I least expected it, but it happens. I immediately looked up, the craft was only about 500' from me, but I saw nothing, but duck are fast.
DJI wants $341 for a replacement craft with battery. That includes a 15% discount, because I can't return the craft with for my refresh policy benefit. Unfortunately is would impossible to find the craft in a river moving that fast, considering the craft weights 245grams. It could be anywhere.

 

[John Locke]

Looks like an easy swim to recover. I always use a rescue float over water to be able to use refresh. Now switched to a Rescue Jacket on my A2. Minis from my experience do not do well when low over water, more so than my others. Bottom sensor gets confused (uncommanded decent) so I rarely fly it less than 20’ over water. Hovering or slow flight makes it worse. Hope you find it. GL

Well, I wish it was an easy recovery. That water runs pretty good, it could have carried that craft hundreds of feet down river. I've been flying this river for several years, I know it well. The mini has worked fantastic, until last week. I stay at about 4 to 5' above the water. I haven't had any issues with the craft sensing water. I do push the limits a little, because the birds can't hear the Mini2 as much as my M2Z, it's very quite, so I can get much closer than with the M2Z. The nearby freeway creates so much background noise that birds don't notice me flying nearby as easy, versus a silent environment.

 

[John Locke]

my guess is that you either flew into something that hit the front left arm (a thin branch sticking up from the water) or a bird attacked it.

Thanks for the analysis. I appreciate the effort, and confirmation of the lack of IMU error. DJI said there was no IMU error also, but I know it appeared in the screen, I saw it. I guess it just wasn't recorded. There was nothing to hit in the middle of the river, it was clearly a bird hit, and I think it was a duck. Ducks can fly straight up for 5 to 8 feet, and that explains it. The duck got spooked and took off. Although I didn't see a duck flying when I looked up VLOS 500' away, I did see ducks come into camera view, as if they paddled right under me. It surprised me to see them because I didn't see them VLOS in the water just seconds before. But I didn't have VLOS of the river's edge nearest me, due to the steep embankment. That's where they came from, so that's the mistake. Although I could have went over to the edge of the river to see the ducks, I just assumed there were no ducks on the edge of the river, where I couldn't see. Bad assumption! Usually ducks paddle away from me when they hear the drone, but in this case I think the duck didn't see me, and sensed eminent danger when it suddenly heard me, then took off out of fear, right under me. I think I "ducked up", then down.

 

[John Locke]

Do you think you could have hit a duck? I have many videos where birds have swooped past close from behind the drone.

Yes. There was evidence of a possible duck collision in the video, but didn't see anything VLOS when it happened. I was puzzled by the "IMU error" I got in the screen when it happened.

 

[Repaid1]

Sucks that she went "ker-plunk"! That was one of the reasons I bought my M2Z, at 4X zoom I (You) would have been well clear of the ducks capturing the same shot. Giving perhaps you (and the ducks) time to react and avoid? I wonder why if you have care refresh your not paying the $225 refresh for loss on the Mini 2 given the new policy?

 

[John Locke]

I th

Sucks that she went "ker-plunk"! That was one of the reasons I bought my M2Z, at 4X zoom I (You) would have been well clear of the ducks capturing the same shot. Giving perhaps you (and the ducks) time to react and avoid? I wonder why if you have care refresh your not paying the $225 refresh for loss on the Mini 2 given the new policy?

Yeah, I thought that was the policy too, $225. But DJI quoted me much more, $341 with a battery. I'll ask them again. Do you know if that policy is written somewhere in their website?

 

[Repaid1]

I th

Yeah, I thought that was the policy too, $225. But DJI quoted me much more, $341 with a battery. I'll ask them again. Do you know if that policy is written somewhere in their website?

I found this with a simple google: DJI Care Refresh Launches Flyaway Coverage: Enjoy Worry-Free Flights - DJI Guides
But you would have had to follow policy and already bound the remote as has been reported since they released new policy 5 months ago.

There is this as well. Buy DJI Care Refresh 1-Year Plan (DJI Mini 2) - DJI Store

 

[spudster]

Sucks that she went "ker-plunk"! That was one of the reasons I bought my M2Z, at 4X zoom/

The Mini 2 also has 4x zoom.

 

[Repaid1]

The Mini 2 also has 4x zoom.

That is all digital and have you seen what it looks like? Not very good from the videos I have seen. This is a M2Z 4X zoom on the fly.

Uploading now...so may take a bit to get to full res.

 

[GadgetGuy]

That is all digital and have you seen what it looks like? Not very good from the videos I have seen. This is a M2Z 4X zoom on the fly.

Uploading now...so may take a bit to get to full res.

M2Z at 4x in 1080p 30fps is phenomenal in good light! I used it almost daily on an Osprey nest with 3 chicks in it last year. I was able to fill the screen with the chicks and their parents, while staying far enough away that I was not disturbing their behavior like chick feeding, let alone risking an attack. The M2P needed to be 4x closer, and was actually was attacked, but fully recovered before reaching the ground, 100 feet below. M2Z is perfect for the task!

 

[GadgetGuy]

I found this with a simple google: DJI Care Refresh Launches Flyaway Coverage: Enjoy Worry-Free Flights - DJI Guides
But you would have had to follow policy and already bound the remote as has been reported since they released new policy 5 months ago.

There is this as well. Buy DJI Care Refresh 1-Year Plan (DJI Mini 2) - DJI Store

As I read it, Flyaway coverage would only apply to verified Flyaways, established through the tablet flight record. A bird strike isn't a FlyAway. The aircraft just took a dive into the water. It didn't actually "fly" away. Otherwise, they would just call the new Flyaway coverage any accident without drone recovery. However, the cost of the much higher FlyAway replacement price does clearly indicate that they are expecting fraud, so maybe they don't even check the tablet logs for any evidence of a flyaway, which almost never happens any more anyway. Anyone know whether proof of a flyaway is no longer required for the FlyAway coverage deductible?

 

[SkyeHigh]

When the event that made your AC dive into the water started the sonar sensor reported 2,6ft.

Sonar sensor?? Well at least he could measure the depth of the river as it sank. [emoji41]

 

[GadgetGuy]

I th

Yeah, I thought that was the policy too, $225. But DJI quoted me much more, $341 with a battery. I'll ask them again. Do you know if that policy is written somewhere in their website?

CostCo offers a retail Mini 2 with an extra battery, a case, a microSD card, and a 90 day no questions asked refund policy for only $439. Even if the Mini 2 is drowned during those 90 days, and the aircraft was unrecoverable, CostCo would still refund your money! So, for only $98 more than DJI is offering, you get an extra battery, another RC, spare props, a combo bag, and a 32GB microSD card, plus a 90 day refund. Sounds like a much better dealt to me!