Why did my Mavic Air 2 fall out of the sky after 1 minute of flight?

[Yorkshire_Pud]

Two facts:
1) the C2C link to your drone stop instantly,

Unless I misunderstand you, you might want to verify this, it might be dangerous to misunderstand how the CSS works .... so .......
I think that you will find that if the "Emergency Motor stop" option is set to "emergency only " and the drone is airborne and has NOT suffered what IT, the-drone, considers to be an 'emergency' then the CSC WILL NOT stop the motors at all.
All that will happen is that the drone will descend in a helix whose speeds correspond to the maximum descent rate, reverse speed, sideways speed and yaw rate for the flight mode. It will continue to do so until the CSC position is released. If the flight mode is cine/tripod the drone will probably slow its descent rate once the VPS starts registering the ground.
I am not sure if the horizontal speeds in N and sports mode will prevent the VPS working so the drone might descend into the ground in those flight modes. I have experiment with this with either a Mavic Mini or a Mini 2 in cine/tripod mode and it was a rather nice looking helix. Sports mode was a bit wild and I didn't bring the drone down low. I can't remember if I tried N mode.

If the "emergency motor stop" option is set to "anytime" then I expect you will find that the CSC will stop the motors once the CSC position has been held for a short delay period i.e. it will not produce an immediate motor stop. Depending on the flight mode the drone may reach significant speed during that delay.
At guess the delay period will be somewhere around 1.7 sec. I think DJI increased the delay period of the Air 3 to 2 seconds.

 

[shb]

The Mavic 3 has a way better design so that the batteries don't simply fall out.

I agree with this 100%. Why DJI stayed with the design that a swollen battery could compromise it's attachment to the drone for so long is beyond me. None of my mavic 3 batteries have swollen at all.

 

[samysys]

Unless I misunderstand you, you might want to verify this, it might be dangerous to misunderstand how the CSS works .... so .......
I think that you will find that if the "Emergency Motor stop" option is set to "emergency only " and the drone is airborne and has NOT suffered what IT/the-drone considers to be an 'emergency' then the CSC WILL NOT stop the motors at all.
All that will happen is that the drone will descend in a helix whose speeds correspond to the maximum descent rate, reverse speed, sideways speed and yaw rate for the flight mode. It will continue to do so until the CSC position is released. If the flight mode is cine/tripod the drone will probably slow its descent rate once the VPS starts registering the ground.
I am not sure if the horizontal speeds in N and sports mode will prevent the VPS working so the drone might descend into the ground in those flight modes. I have experiment with this with either a Mavic Mini or a Mini 2 in cine/tripod mode and it was a rather ice looking helix. Sports mode was a bit wild and I didn't bring the drone down low. I can't remember if I tried N mode.

If the "emergency motor stop" option is set to "anytime" then I expect you will find that the CSC will stop the motors once the CSC position has been held for a short delay period i.e. it will not produce an immediate motor stop. Depending on the flight mode the drone may reach significant speed during that delay.
At guess the delay period will be somewhere around 1.7 sec. I think DJI increased the delay period of the Air 3 to 2 seconds.

I believe you was referring to Combination Stick Command (CSC). I understand and agree with you but do not understand how two post are related.

and the "C2C link" as I have mentioned, it just means the radio link between the drone and the controller... in case that confuse you.

 

[Yorkshire_Pud]

and the "C2C link" as I have mentioned, it just means the radio link between the drone and the controller... in case that confuse you.

Ahhh, it did and it might confuse others, "control connection" or "control linkage" might be better wording than "CSC link".
Thanks for the explanation.

 

[rjwmorrell]

A LiPo doesn't swell (aka PUFF) quickly unless there is some type of catastrophic discharge event (short in the cells, short in the aircraft wiring, short in the charge) and it puffs quickly with a high probability of catching fire if conditions are just right.

Sorry BigAl07, I'm going to disagree with you on this point.

Numerous battery related sites and forums all mention how over time LiPo batteries can and will swell from repeated uses simply from the change in chemical composition of the electrolytes as gases build up in the battery. The DJI manual warns against using a swollen battery. I don't think any physical damage is necessary, though I have seen a video where the total conflagration of a LiPo was very rapid after puncture.

 

[shb]

Sorry BigAl07, I'm going to disagree with you on this point.

Numerous battery related sites and forums all mention how over time LiPo batteries can and will swell from repeated uses simply from the change in chemical composition of the electrolytes as gases build up in the battery. The DJI manual warns against using a swollen battery. I don't think any physical damage is necessary, though I have seen a video where the total conflagration of a LiPo was very rapid after puncture.

All my mavic pro batteries swelled without being damaged at all.

 

[BigAl07]

Sorry BigAl07, I'm going to disagree with you on this point.

Numerous battery related sites and forums all mention how over time LiPo batteries can and will swell from repeated uses simply from the change in chemical composition of the electrolytes as gases build up in the battery. The DJI manual warns against using a swollen battery. I don't think any physical damage is necessary, though I have seen a video where the total conflagration of a LiPo was very rapid after puncture.

Your talking about two totally different things. This was a SWELLING during a SINGLE FLIGHT (aka CRASH). You're talking about the degradation, over time, of a modern day Lipo battery. You're comparing apples to mudholes.

Under NORMAL use they swell "Gradually". Sometimes over the course of just a few weeks or months but gradually. When a battery "Puffs" suddenly it's not from "Normal Use". I've been "doing this" with rechargeable batteries for decades now. I have seen/caused just about every type of battery failure possible including the battery igniting into a smoke spewing blow torch inferno in the back floorboard of my car.

Normal Use battery swelling is slow and over time and ALSO a normal part of the degradation of the internals of the battery. Going from unnoticeable to this degree of PUFF in a single flight, immediately after a catastrophic impact is anything but NORMAL.

 

[Capt KO]

Sorry for your loss. Looks like an unexplained catastrophic failure. Nature of the beast apparently. I'm sure my A2 has an uncertain life expectancy as well. Time for an upgrade?

 

[wmead]

If I missed it, I apologize. However there is another way that batteries can fail that is instantaneous: the cells are wired together via welded metal straps. It is possible for a defective weld that has been in a vibrational environment to just "pop" at a seemingly random time. If the battery had not broken apart in the crash, checking the output with a voltmeter could tell you whether there was an internal disconnect. With a destructive inspection, you might be able to find a broken weld. You could check by ejecting a live battery, but I suspect that a sudden, catastrophic failure would not show up in a log file.

 

[AZDave]

Sorry BigAl07, I'm going to disagree with you on this point.

Numerous battery related sites and forums all mention how over time LiPo batteries can and will swell from repeated uses simply from the change in chemical composition of the electrolytes as gases build up in the battery. The DJI manual warns against using a swollen battery. I don't think any physical damage is necessary, though I have seen a video where the total conflagration of a LiPo was very rapid after puncture.

He said "quickly", and he's correct. A LiPo battery is highly unlikely to swell quickly (i.e., during a flight but not before) unless it was damaged.

 

[AZDave]

All my mavic pro batteries swelled without being damaged at all.

But not "quickly", right?

 

[caseSensitive]

The distortion is NOT swelling. That is from contact with the ground. Are you sure you had it locked in fully?

Yes, That left corner looks like an impact rather than swelling. Possibly fell out and hit something pretty hard to cause that.

 

[Phantomrain.org]

That is the exact same warning you get when your battery gets wet and disconnects from the controller and crashes, so the battery got twisted up before this flight and got unseated from heating up when flying makes for a good case.

Phantomrain.org
Gear to fly in the Rain . Land on the Water.

 

[shb]

But not "quickly", right?

Right.

 

[MNewman]

Well, at this point, I'm a little terrified to get another drone. I do a lot of real estate photography work, which means sometimes being asked to fly in a city or in a crowded residential neighborhood, and it's pretty disconcerting to know that at any moment, the drone battery can just fail out of the blue and fall out of the sky, potentially killing someone walking by underneath. Even with liability insurance... I don't want to potentially kill someone.

 

[rjwmorrell]

Get a Mini 3 or Mini 3 Pro. The weight is under 250g, less likely to cause serious injury, and just diligently rotate batteries.

 

[shb]

I have three batteries -- and I absolutely do not know if the battery that was in the drone when I crashed into the tree branch was the same as the battery I flew when the drone fell out of the sky

When I crashed my mavic 3 pro in Thailand in July, and recovered it, the first thing I did was taped white tape to the battery, and wrote a C on it, so I would know which one it was. I have four. I think it's pretty unlikely that a good battery and drone will have the battery fall out in flight. Specially because the mavic 3 gives a warning if the battery isn't inserted properly.

 

[BigAl07]

Well, at this point, I'm a little terrified to get another drone. I do a lot of real estate photography work, which means sometimes being asked to fly in a city or in a crowded residential neighborhood, and it's pretty disconcerting to know that at any moment, the drone battery can just fail out of the blue and fall out of the sky, potentially killing someone walking by underneath. Even with liability insurance... I don't want to potentially kill someone.

This has ALWAYS been the case with Aviation. This is exactly why Manned Aircraft have redundant systems for their redundant systems. The difference here is that with the Mavic and similar UAS, the battery is a Single Failure Point and our UAS glide like a ROCK!

This is why we PLAN out flight and do everything in our power to minimize RISK even to the point of NOT making a flight if we can do it with a high degree of safety factored in.

One rule I've preached to every single student I've ever taught to fly (I started teaching R/C flight in 1984) is, "If you FLY them you will eventually CRASH them. The ONLY way to NOT CRASH is to NOT FLY! "

Today's UAS are LEAPS and BOUNDS safer than the ones just a decade ago but things still fail, people still make dumb mistakes, and crap happens. Fly safe and do everything you can to MINIMIZE the risk.

 

[MNewman]

This has ALWAYS been the case with Aviation. This is exactly why Manned Aircraft have redundant systems for their redundant systems. The difference here is that with the Mavic and similar UAS, the battery is a Single Failure Point and our UAS glide like a ROCK!

This is why we PLAN out flight and do everything in our power to minimize RISK even to the point of NOT making a flight if we can do it with a high degree of safety factored in.

One rule I've preached to every single student I've ever taught to fly (I started teaching R/C flight in 1984) is, "If you FLY them you will eventually CRASH them. The ONLY way to NOT CRASH is to NOT FLY! "

Today's UAS are LEAPS and BOUNDS safer than the ones just a decade ago but things still fail, people still make dumb mistakes, and crap happens. Fly safe and do everything you can to MINIMIZE the risk.

So then in regards to real estate photography, would you suggest only shooting rural properties with expansive land and completely avoiding the suburbs and city?

 

[shb]

So then in regards to real estate photography, would you suggest only shooting rural properties with expansive land and completely avoiding the suburbs and city?

I think DJI drones are extremely reliable. They very, very, rarely just fall out of the sky. Even the motors hardly ever fail in flight. If you are worried about the battery, you could tape it in so it can't fall out. I actually fly in urban areas 95% of the time.