P3S fell from sky

[Scoot88]

Hi,
Just seeking assistance in understanding why my P3S fell from the sky. This link is from that flight,
Phantom Log Viewer - PhantomHelp.com
It occurred during my second short flight late that afternoon. Complete prelim flight check carried out as per normal including prop fastening checks (as others have said in their fall from sky events this was definitely done correctly. Why spend so much money and not do it.),The weather was great flying conditions very little wind and great visibility. I could see the event clearly when it happened maybe 150-200m away from me. It just dropped like a stone!
Fortunately the aircraft was recovered just short of an additional 100m cliff fall. This was done with the help of an able Mavic Pro enthusiast who ran a few quick passes and located the AC and hovered over the location until I could get to it. So many thanks to him for his assistance!
Three of the four prop hubs were attached with one missing and very little prop debris at the crash site. The hanger to the gimbal was bent up and a few cracks on the shell, and one broken leg. And that is without running it up. I was surprised how robust they are with exception of the gimbal, I was expecting componets everywhere..
At what point do you write it off?
From reading others sky fall events and knowing that I had the props fastened correctly, and the unlikelihood of it being covered by warranty, is there anything you can do to ensure that the props cannot fly off? I am just worried it will happen again. How many hours are the props rated for? This set had only done about 26hrs I think.
Regards Scoot88

 

[alokbhargava]

As there are no records of coming it down to the ground, it looks battery popped out/ got disconnected during the flight. Is that right?

 

[Waylander]

Hi Scoot88
Yes I think alokbhargava, made a good point, but also 26 hours on a set of props, sounds a lot, how many times were they screwed on and off in that time...?

Tthe thread in the props, I take it were cut into the prop material, and not like some older props that had an alloy insert, so it might be the case that the thread failed.

As an aside, does anyone know if DJI has ever issued a life expectancy for a set of props, specifically thread wear...?

Regards
waylander

 

[msinger]

Your flight log shows you lost the prop-mid flight at 4m 13.2s in your flight log. You could confirm this by viewing the data in your DAT flight log with DatCon. You can see the Phantom started to tumble in the air and was descending quickly on its own with no throttle stick input.

Here's the flight path showing where the crash occurred:

The prop was most likely either damaged or not installed properly.

 

[Scoot88]

As there are no records of coming it down to the ground, it looks battery popped out/ got disconnected during the flight. Is that right?

No the battery was still in place and on when I recovered the AC. I honestly think that the prop came off just not sure why as it was fastened in the same fashion and to the same degree as the others. I searched the crash site again and found a few more bits of my props but not the missing one. I was hoping to inspect the prop's thread to see if it had stripped out.

 

[Scoot88]

Hi Scoot88
Yes I think alokbhargava, made a good point, but also 26 hours on a set of props, sounds a lot, how many times were they screwed on and off in that time...?

Tthe thread in the props, I take it were cut into the prop material, and not like some older props that had an alloy insert, so it might be the case that the thread failed.

As an aside, does anyone know if DJI has ever issued a life expectancy for a set of props, specifically thread wear...?

Regards
waylander

Not sure on the number of times exactly.Depends if I am travelling or in a fixed location. If in a fixed location I generally just leave the props on to save wear and tear. I will be more thorough and record all that information in my own flight log rather than relying on just the flight time statistics as recorded in the DJI app. It would be good if you could enter that sort of information in there as you go, say with a flight check list.
So is there any guidelines as to how many hours props and engines are rated for? I would hate to go through this again by making the same mistake. Regards Scoot88

 

[danny lewis]

Bird strike


Sent from my iPhone using PhantomPilots

 

[Waylander]

Hey Danny

Good point, it could have been a bird strike, it is a possibility, but... have you ever seen one, or had one ?, I once had a Hawk have a good luck at mine, came at it 4 - 5 times, circling comining in with tallons out etc, but never actualy went as far as to get a hold of it, generally birds don't crash into one another, and at the 20 mph speed the op was doing any bird worth it's salt could have taken evasive action... but it is possible, but so is a prop coming off, and of the few occasions I have hit something with a prop there has always been something of the prop left behind, the OP says he could not find any sign of it.
Waylander