Strange Crash today

[d33p]

I had a strange crash today.

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So I suddenly heard a grinding propeller noise and then suddenly the Mavic dove to the ground. As you can see on the video it actually manages to level the mavic right before hitting the ground.

I was lucky this happened so close and on the ice, but the mavic was basically submerged in wet slurpy snow for some time.

The propeller on the side that dove down first is broken, so Im wondering if this happened in air and was the cause, but then it maybe wouldnt be able to level at all like it did?

There is no warnings or errors from the flight.

 

[Former Member]

Did you look for prop fragments near the spot it went down? Looks like a ground strike that broke the props to me.

 

[sar104]

Need the flight log and, preferably, the DAT file from the aircraft or the mobile device.

 

[jrose42]

How cold was it? Was it snowing at the time? Could moisture have gotten into the motors during flight? Have you tried flying it after replacing the damaged prop? Wondering if it was just a motor failure mid-air.

 

[d33p]

Here is the log from the GO app:

DJI Flight Log Viewer - PhantomHelp.com

It was around -2 Celsius and not snowing, I didnt find any of the prop fragments, the snow was way to deep.

Is there any tools to analyze the dat files from the mavic? Havent turned it on yet (still drying)

 

[d33p]

I just noticed this, so the back propeller has cutted into the forward leg. That supports what I heard in air. But how is this possible? Wind blowing the forward leg back into the back propeller?

 

[Just_nick]

If the leg wasn't locked in place, sure.

 

[d33p]

Im pretty sure the leg was fully extended, but of course it could be a possibility that it wasn´t.

I was able to fly it without any problems same flight prior to this, if the leg wasnt locked (less than 90 degress) wouldnt I have noticed it? I mean im pretty sure the flight performance would have been bad?

 

[matsemann]

I find it hard to believe that the leg folded in during flight. It has to be at an angle of less than 90 degrees to not automatically fold out forward. I am sure those damages are from the after the crash, when the leg folded in and the motors kept running.

 

[ac0j]

I think it iced up, made a noise when ice flew off, came down, THEN the prop hit the leg and broke apart.

 

[matsemann]

I am new to the drone world, but flying is my occupation, so I know a few things about icing. I am sure that the props on a drone is susceptible to ice up. Thinner airfoils are more prone to pick up ice. This is how the fan on our engine looked like after taxiing a few minutes in freezing fog:

 

[Lake_Flyer]

I think it iced up, made a noise when ice flew off, came down, THEN the prop hit the leg and broke apart.

Exactly my thoughts. That kind of weather is the best recipe for icing.

 

[Lake_Flyer]

View attachment 31661 I am new to the drone world, but flying is my occupation, so I know a few things about icing. I am sure that the props on a drone is susceptible to ice up. Thinner airfoils are more prone to pick up ice. This is how the fan on our engine looked like after taxiing a few minutes in freezing fog:

You're correct. Drone propellors are actually very prone to icing. It was an important subject during my Remotely Piloted Aircraft ground school.

 

[kakao]

Lesson learned for me ..

 

[Chunter]

I've flown in minus weather with snow, only minus 1 or 2 but it was fine.upload the logs and get someone who know what they're doing to look at them.

 

[Lake_Flyer]

I've flown in minus weather with snow, only minus 1 or 2 but it was fine.upload the logs and get someone who know what they're doing to look at them.

Light snow is usually fine. Freezing fog isn't.

 

[rfc]

Post the logs/.dat files. Only way to know what happened.

 

[WGNF911]

When I saw the video, the first thing I though was icing. Expect icing when the temp is slightly above freezing or colder AND there is visible moisture. Visible moisture would include fog, mist, frozen rain, rain, or sleet. I couldn’t see the pic of the damage well but it could have come from ice shedding off that blade. The Mavic has no anti-ice or deice systems so don’t fly when icing is possible. Basically, the ice will collect on the leading edge of the props and prevent it from producing lift. If you pay close enough attention, I would think you would see an increase in RPM for any given flight profile. Essentially, the aircraft, sensing loss of lift will speed up RPM to compensate until ice buildup on the prop totally disrupts lift and it falls.

 

[Soarmax]

I think your crash was caused by “Windchill.” I don’t think your blades “iced up.” I think they “froze up” due to windchill. Even though the ambient temperature was -2 C, the blades were probably about -10 C. Windchill is caused by moisture in the air. More moisture, more windchill. Windchill doesn’t only apply to skin. It can be applied to any material, be it plastic or metals.

I had a similar experience about three or four years ago when I was flying a Quad at my RC Clubs annual “Freeze Fly” on New Years Day. It had snowed the day before about 4” and the air temperature was about 35 F. Clear and sunny. The snow was melting some due to sunshine.

I had taken off and have the Quad in a hover at about 10 feet. After about two minutes, it just fell out of the sky, did a couple flips on the way down and landed upside down in the snow. Turns out that it had thrown a prop blade. Replace the prop and it flew fine after that. Had flown the Quad several times before, but at warmer temperatures. I’m thinking that particular prop had some internal stresses that caused it to fail due to the extra cold conditions.

I think your prop blade failed in flight due to internal stresses caused by possible prior damage, and stress caused by windchill. Crashing into soft snow would not do the damage shown on your prop blade.

You were kind of pushing the limits in flying in that cold of temperature. Keep in mind that Lipo Batteries do not perform well at temperatures less that 10 C.

 

[djaco]

I had a strange crash today.

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So I suddenly heard a grinding propeller noise and then suddenly the Mavic dove to the ground. As you can see on the video it actually manages to level the mavic right before hitting the ground.

I was lucky this happened so close and on the ice, but the mavic was basically submerged in wet slurpy snow for some time.

The propeller on the side that dove down first is broken, so Im wondering if this happened in air and was the cause, but then it maybe wouldnt be able to level at all like it did?

There is no warnings or errors from the flight.

View attachment 31573

I had a prop strike on one of my flights, MP hit some very thin branches, recovered to level flight, no issues, no apparent damage, or so I thought, a couple of flights later, I heard a grinding noise at takeoff, one motor had stopped, when I checked each prop, one of the 3 hooks had broken off, and fell into the motor, I removed the prop, and piece of plastic in the motor. Problem solved.