Get more from your Mavic
The largest Mavic community in the world
Join Us Now

Sudden Catastrophic Flight Incident

montypython

New Member
Joined
Apr 6, 2021
Messages
2
Reactions
0
Age
33
Location
Salt Lake City, UT
Was flying real estate aerials for a client using their Mavic 2 Pro. Admittedly, got carried away and pushed the range of the flight, though I knew airspace was clear, doing a high orbit of an apartment complex amenity.

Suddenly lost signal and attempted to sprint closer to the drone to re-establish connectivity and locate a hovering drone, but it was no longer airborne. Found it crashed at the base of a 3-4 ft bush on the edge of a parking lot and the broken and swollen battered battery pack 10 ft away. Flight altitude was in the neighborhood of 150-200 ft.

Since settings were RTH with loss of signal, emergency landing at low battery, and clearance was sufficient to fly over any obstacles in an automatic RTH, I'm curious if this was a swollen battery pack (direct Florida sun) that dislodged, or some other failure. I've looked through the log on AirData but can't find an indication.

Also, lesson learned about losing line-of-sight for any amount of time. I'm sick to my stomach over how much worse it could've been.

Log is attached.

Thank you for any insights. I have resolved to be much more conservative in my flying.
 

Attachments

  • DJIFlightRecord_2021-04-09_[07-17-19].txt
    466.8 KB · Views: 51

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
2,387
Reactions
6,080
Age
53
Location
Sweden
Yep ... it's very likely that this was due to a sudden swelling making the battery to disconnect. So the RC disconnect you had was due to the sudden power loss & the AC went dead in the air.

No signs of any sudden movements not fitting the maneuver you did there ... the battery didn't show any signs of something soon to happen either, cell voltage was good. The RC connection also was at 100% to the very end.

All relevant data in the chart below, markers placed in the very end of the log & showing the values in the legend ... click on it to make it larger.

1617746257046.png
 

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
2,387
Reactions
6,080
Age
53
Location
Sweden
... is the dramatic sharp drop black the altitude and the bounce on the ground?

No... nothing of the touchdown is in the log as the power was cut much earlier meaning that the RC connection also was terminated & with that the possibility for the app to record the log further.

The Black graph is the yaw angle from North (0 degrees) on a vertical +/- 180 degree axis... so that drop in the graph is when the yaw angle passes South.
 

CactusJackSlade

Well-Known Member
Joined
Oct 17, 2016
Messages
895
Reactions
665
Yup, I was surprised to see one of my batteries was a bit puffed, I only noticed it when I felt the battery was hard to get to snap in, I am lucky I found it, this issue has caused a few crashes like this. I believe they had a bad batch of batteries.... and of course most are out of warranty before you find out. Sorry for your crash :-(
 

Uncle Hoser

Well-Known Member
Joined
Jan 16, 2021
Messages
56
Reactions
100
Age
66
Location
Arizona, USA
A bit off-topic, but how do you get that data from the drone and convert it to something readable?????? I'm a new guy, don't beat me up too bad!
 

sar104

Dic mihi solum facta, domina.
Premium Pilot
Joined
May 27, 2017
Messages
12,814
Reactions
16,574
Location
Los Alamos, NM
A bit off-topic, but how do you get that data from the drone and convert it to something readable?????? I'm a new guy, don't beat me up too bad!

 

Uncle Hoser

Well-Known Member
Joined
Jan 16, 2021
Messages
56
Reactions
100
Age
66
Location
Arizona, USA
WOW!!! Thank you, sir! What an amazing array of information!

I haven't been here long enough to dig back into the archives. I'm learning every day...and if the wind would let up a bit, I'll get back to learning to fly!
 
  • Like
Reactions: SlugHead and sar104

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
2,387
Reactions
6,080
Age
53
Location
Sweden
Sorry for the crash. Just wondering if the battery has been inspected after the crash. Was it actually swollen ?
From the first post ...

"... Found it crashed at the base of a 3-4 ft bush on the edge of a parking lot and the broken and swollen battered battery pack 10 ft away"
 
  • Like
Reactions: Wilbur and kidroc

Majormaxie

New Member
Joined
Jan 26, 2021
Messages
2
Reactions
0
Age
68
Location
florida
Indeed! Such happened to me and I got to see it. Was checking.

When checking out my Mavic Pro for Halloween (2020), I was hovering at 65-70 ft. I saw the battery pop-out & fall, followed by my drone slamming into the street. Battery was swollen and although it clicked-in securely at take off, it swelled and dislodged. Upon retrieval, battery definitely distorted (and “squeezable”). Burned up one of my Refresh replacements. (motors destroyed)
 

Mavricbird

Member
Joined
Aug 1, 2020
Messages
13
Reactions
9
Age
75
Location
Glenreagh nsw Australia
Same thing happen to me last month sent my drone to repairs it was out of warranty DJI replaced it with a new one at a cost of $650.00 I didn't send the battery I should have. I have 3 swollen batteries out of 5 all with only 32 chargers DJI has organized to have them sent back to them to be analyzed that I did yesterday now waiting so far I have had a good response from DJI. To be on the safe side I now put a thin plastic zip tire around the drone to stop the battery coming out. I will be checking the batteries from now.
 
  • Like
Reactions: danbo98042

BigAl07

Administrator
Staff Member
Premium Pilot
Joined
Jun 1, 2017
Messages
4,703
Reactions
9,693
Age
50
Location
Western NC, USA
Same thing happen to me last month sent my drone to repairs it was out of warranty DJI replaced it with a new one at a cost of $650.00 I didn't send the battery I should have. I have 3 swollen batteries out of 5 all with only 32 chargers DJI has organized to have them sent back to them to be analyzed that I did yesterday now waiting so far I have had a good response from DJI. To be on the safe side I now put a thin plastic zip tire around the drone to stop the battery coming out. I will be checking the batteries from now.

The danger of a swollen battery is more than "just" popping out. A PUFFED battery is a physical indicator that the battery is degrading and/or damaged. A puffed battery should not be used for FLIGHT any longer. If it's very slightly puffed it can be used for testing/calibrating ETC but do not trust a PUFFED battery in the air. If it's more than a very minor "puff" it should be properly disposed of and not trusted.

PUFFING is an indicator of Electrolyte Decomposition. This is a normal process of a Lipo battery but the process is exaggerated through misuse. Over Charging, Over Discharging, Leaving stored at a full Charge, Over Heated in Storage, Charged/Discharged while battery is above normal operating temps, and normal Charge/Discharge are ALL reasons that cause a Lipo to "Puff". All Lipos will eventually PUFF even if treated perfectly.

A Lipo can PUFF from a single significant misuse, repeated minor misuses, and normal wear/tear of Charge/Discharge cycles.

One thing to keep in mind is that the GAS that causes the pack to PUFF is actually Oxygen! This FUEL source can easily ignite causing a significantly HOT and INTENSE fire that is not easy to extinguish. I literally melted ASPHALT when I had a mishap with a large LIPO for one of my 3D helicopters. I heard the "CRACK" of the leads touching, they welded together and I tossed the pack out of the car (yes in the floorboard of my wife's car). It landed on the asphalt and self destructed in a nasty, dark smoke, ball of fire. When it went out (well mostly, the plastic smoldered until doused with lots of water) it had burned a hole into the asphalt that was there a few years later when they resurfaced the parking area.

Not EVERY puffed battery will catch fire but enough have over the years to warrant a very real concern for our industry. The more the PUFF the higher the likelihood of it catching fire (or exploding) and a PUFFED battery is much more sensitive to impact and physical abuse.

Don't risk your entire aircraft to save a couple hundred $$ because when it fails it will probably cost significantly MORE!!
 

sar104

Dic mihi solum facta, domina.
Premium Pilot
Joined
May 27, 2017
Messages
12,814
Reactions
16,574
Location
Los Alamos, NM
The danger of a swollen battery is more than "just" popping out. A PUFFED battery is a physical indicator that the battery is degrading and/or damaged. A puffed battery should not be used for FLIGHT any longer. If it's very slightly puffed it can be used for testing/calibrating ETC but do not trust a PUFFED battery in the air. If it's more than a very minor "puff" it should be properly disposed of and not trusted.

PUFFING is an indicator of Electrolyte Decomposition. This is a normal process of a Lipo battery but the process is exaggerated through misuse. Over Charging, Over Discharging, Leaving stored at a full Charge, Over Heated in Storage, Charged/Discharged while battery is above normal operating temps, and normal Charge/Discharge are ALL reasons that cause a Lipo to "Puff". All Lipos will eventually PUFF even if treated perfectly.

A Lipo can PUFF from a single significant misuse, repeated minor misuses, and normal wear/tear of Charge/Discharge cycles.

One thing to keep in mind is that the GAS that causes the pack to PUFF is actually Oxygen! This FUEL source can easily ignite causing a significantly HOT and INTENSE fire that is not easy to extinguish. I literally melted ASPHALT when I had a mishap with a large LIPO for one of my 3D helicopters. I heard the "CRACK" of the leads touching, they welded together and I tossed the pack out of the car (yes in the floorboard of my wife's car). It landed on the asphalt and self destructed in a nasty, dark smoke, ball of fire. When it went out (well mostly, the plastic smoldered until doused with lots of water) it had burned a hole into the asphalt that was there a few years later when they resurfaced the parking area.

Not EVERY puffed battery will catch fire but enough have over the years to warrant a very real concern for our industry. The more the PUFF the higher the likelihood of it catching fire (or exploding) and a PUFFED battery is much more sensitive to impact and physical abuse.

Don't risk your entire aircraft to save a couple hundred $$ because when it fails it will probably cost significantly MORE!!

We had a battery fire incident here just last month. It was a Skydio of some kind, not DJI, but the battery disconnected at around 200 ft AGL and the aircraft fell to the ground. The impact ejected the battery which then bounced under a nearby vehicle and caught fire. That prompted a full fire department and hazmat response. Much excitement, policy revisions and other actions.
 

mereflyer

Well-Known Member
Joined
Nov 27, 2018
Messages
193
Reactions
204
Age
78
Here is my very simple, easy answer to the problem of battery disconnections in flight.
See the attached pictures:
 

Attachments

  • DSCN2883.resized.v01.jpg
    DSCN2883.resized.v01.jpg
    720.8 KB · Views: 75
  • Modified DSCN2881.resized.jpg
    Modified DSCN2881.resized.jpg
    768 KB · Views: 71
  • Like
Reactions: Galeforce1

BigAl07

Administrator
Staff Member
Premium Pilot
Joined
Jun 1, 2017
Messages
4,703
Reactions
9,693
Age
50
Location
Western NC, USA
We had a battery fire incident here just last month. It was a Skydio of some kind, not DJI, but the battery disconnected at around 200 ft AGL and the aircraft fell to the ground. The impact ejected the battery which then bounced under a nearby vehicle and caught fire. That prompted a full fire department and hazmat response. Much excitement, policy revisions and other actions.
Sounds like an exciting afternoon LOL! Hopefully the fire was short lived and didn't ignite the car.
 

spudster

Member
Joined
Mar 24, 2021
Messages
22
Reactions
22
Age
68
Location
Cape Coral FL
EVERYONE should store their batteries in a LiPo sack. It's cheap insurance. They make them for a reason. LiPo fires are near impossible to put out. If it happens in your house you are in big trouble as you won't be able to put it out. Water only makes it worse, Best bet is to cover it with dirt or sand.

 

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
2,387
Reactions
6,080
Age
53
Location
Sweden
Here is my very simple, easy answer to the problem of battery disconnections in flight.
See the attached pictures:
I'm afraid that those rubber bands will not do anything at all to prevent the the battery from disconnecting ... maybe they stop the battery from being totally dislodged but the AC will free fall anyway.

As said above ... don't use batteries that you know have swelled, it's just waiting for something even worse to happen.

To stop a battery from disconnecting (maybe) due to a sudden swelling mid air, something more rigid is needed as the forces are way to big for a pair of rubber bands. Something like velcro bands ... i.e. fpv battery straps, like that below.

This might give you just enough to get the AC down without a disconnect ... & make you see the swelling and take that battery out from use.

1617865977723.png
 

Titannz

Member
Joined
Sep 17, 2018
Messages
6
Reactions
1
Age
58
I bought my MP2 pro a few months when released in 2018..still have the 3 original batteries which of all had about 40 odd charges. I don't use my Mavic that often..but when i do i always the batteries not only by visually checking the bellies but also placing them on a flat table and make sure there is no wobble. Despite this caution from what i have read here is it true that they can go from looking perfect to bloating up without warning when in the air?
 
  • Like
Reactions: BigAl07

New Threads

Forum statistics

Threads
104,384
Messages
1,208,522
Members
133,054
Latest member
smb8129