I was very, very lucky ... (birdstrike?) on Mavic 2 Pro

[Yorkshire_Pud]

@Ronny St.
The .dat have no value to me as they are encrypted but I keep them anyway.

Just for reference, that depends on the drone.
The 'phone' DATs from the mini 2 are encrypted but the 'phone' DAT's from the M2P/Z, mavic mini, FPV and Mini 3 Pro are not encrypted. I own examples of the first 5 and have downloaded Mini 3 Pro phone DATs from 'crash' threads that CsvView can read.
Somewhere after the Phantom 3 the drone DAT's were, and remain, encrypted, which is a real bummer and they continue to record data right the way through disconnections. Phone DAT's lose data during disconnections.

 

[twickers14]

True, but I am willing to learn as much as possible from those who know a lot more of that matter than I do

Sure you do. Good luck. I’m in JFK at the moment. Deffo no flying here unless you’re in an airliner!

 

[BudWalker]

I'm afraid I had the flight logs set to synchronize automatically... Should I turn it off for future flights?

Edit: I checked it and found a DAT file with FLY006 in the name, as you told me
I will attach it here. I had looked to those files before, but it automatically opens Cyberlink Photo Director 8 and tells me the file cannot be opened. So I do not know what software I have to use to open it nor what can be found in DAT files

Looks to me like a bird strike or it ran into something at an altitude of 146 meters above the launch site. At 475.709 secs the M2 abruptly accelerated along the negative X axis. I.e., it abruptly accelerated backwards.

And, there is this from the eventLog

475.586 : 26758 [L-FDI][CTRL]: fault on , impact_in_air
475.606 : 26759 [L-RC]craft ctrl failed!!!
475.746 : 26766 [L-FDI][CTRL]: fault off, impact_in_air

And, then the gyro data shows the M2 pitching down, rolling CW and rotating CW.


I had a bird strike with my M2, Take a look
My bird strike

 

[Ronny St.]

It's personal preference, I want the DATs and I don't want someone else holding my flight history so I have only synced a very few logs.

To me your drone appears to be low on its right hand side and it looks as if the right rear arm is touching the table whereas the left rear arm is not. A quick glance at mine suggests that both rear motors should be clear of the table top.

It's personal preference, I want the DATs and I don't want someone else holding my flight history so I have only synced a very few logs.

To me your drone appears to be low on its right hand side and it looks as if the right rear arm is touching the table whereas the left rear arm is not. A quick glance at mine suggests that both rear motors should be clear of the table top.

Though I would wait and see what others think.

With regards to what happened to the prop,
It's difficult to say, do you normally remove the props at the end of a day's flying?

If the props are not properly fitted, meaning they have not been rotated far enough for them to lock into place, then the shaft that runs through their centre sticks up above the top of the prop's hub.
When the prop is correctly fitted then the top of the shaft is flush with, or perhaps slightly below, the top of the prop's hub.

Also for an incorrectly fitted prop to be thrown in the release direction, let's call that forward, the motor would have to deccelerate very rapidly. Plus the drag (air resistance) of a spinning prop would tend to move it 'backwards', in the direction to make it 'lock' as would motor accelerations.

Given that the props can 'bite' I am not inclined to try incorrectly/ incompletely fitting a prop to see whether any deccelerations are strong enough to throw a prop forward.
Could the catches of a prop break?
I have had one out of the three catches on each M2P/Zprop break in an indoor mishap but when inspecting the drone the motor of that prop felt rough and I think the catch fragment was catching on the motor windings.

There are at least two threads where 'mavic' props broke, at the hub, in mid air but they were/are, I think, Air or Air 2 or Air 2s and I think they have only to catches per prop. The M2P has three catches so might be more secure. At least one of those 'Air lodt a blade but remained airborne and with difficulty controllable and it was brought home. I did test a M2P with half a blade cut off, from memory the drone remained controllable if the butchered prop was on the rear but was uncontrollable if that prop was on the front. Those tests were indoor flights and literally take off or try to take off, climb to a height of a couple of inches see how it handled for a few seconds then land. The upward looking vision sensor registered the ceiling and kept the drone low.

Well, I must admit that I never noticed that the four legs didn't touch a horizontal plane exactly ... I took some more pictures where it can be seen that at the left rear the 'support' on the drone (sorry, I don't know how to name that correctly) is about 1 mm above that table, lifting the left hand rear site up and that is magnified by the length of the arm. It is hard to see on the picture, but if you know it, it is clear to see:


I noticed that the arm, when folded, come to some rubber damper (see following picture), but that seems ok on both sides.



I just wondered that if one of those 2 dampers is not 100% exactly as the other one, it can 'tilt' that side a bit up and that tilt would extend to the entire arm length.
Is that something to be worried about?

Concerning the props: I never remove them, but I must admit I have been looking how they are attached/detached just to understand how they are fitted to the AC. So I am pretty sure I did attach them correctly previous to the flight.

I don't know if the following picture can add some information, it is the taken from the two props I removed. At the left is all that remains of the left front prop (bits of the attachment) and at the right one can clearly see that the tips from the right front prop are gone. As I said before, the right arm was folded backwards, almost to the position to 'park' it.



I really hope to get confidence again to launch my bird without having to fear that something is wrong and might cause a fatal loss

 

[Ronny St.]

Looks to me like a bird strike or it ran into something at an altitude of 146 meters above the launch site. At 475.709 secs the M2 abruptly accelerated along the negative X axis. I.e., it abruptly accelerated backwards.
View attachment 162817
And, there is this from the eventLog

475.586 : 26758 [L-FDI][CTRL]: fault on , impact_in_air
475.606 : 26759 [L-RC]craft ctrl failed!!!
475.746 : 26766 [L-FDI][CTRL]: fault off, impact_in_air

And, then the gyro data shows the M2 pitching down, rolling CW and rotating CW.
View attachment 162818

I had a bird strike with my M2, Take a look
My bird strike

Thanks for contributing to this topic, Budwalker. I've read the topic you refer to and learned some more about our drones. I did notice two birds in the sky at the time of flight, but I did not see them close to my M2P, nevertheless they could have been since I also regularly looked at my SC to follow up the path of flight.

 

[Cymruflyer]

You are very lucky that your camera gimbal did not get damaged, that usually happens when they drop to the ground.

 

[Ronny St.]

You are very lucky that your camera gimbal did not get damaged, that usually happens when they drop to the ground.

Yes, I know, hence the title of this topic It landed in high grasses (see #1) that were mowed within 30 minutes of the crash.

Btw, if some other M2P owners are following this: I am very interested to know whether the legs of your drone all touch the ground or only the front legs (as with Yorkshire_Pud).

 

[Yorkshire_Pud]

I am very interested to know whether the legs of your drone all touch the ground or only the front legs (as with Yorkshire_Pud).

Ahh if I gave you than impression then sorry I have mislead you. On a flat surface the rear arms do not touch the surface they are clear of it by equal amounts, only the front arms and the two feet of the bottom cover should touch the ground.

The projection you arrow seems normal to me, they may be part of the rotation stop 'system' for the arm in the flying postition

 

[Ronny St.]

Ahh if I gave you than impression then sorry I have mislead you. On a flat surface the rear arms do not touch the surface they are clear of it by equal amounts, only the front arms and the two feet of the bottom cover should touch the ground.

The projection you arrow seems normal to me, they may be part of the rotation stop 'system' for the arm in the flying postition

Well, here the left arm does touch the ground, but I don't know if that was like that before. Never payed attention to it. I hope this is not a sign of something being wrong. When I turn both rear arms beyond the fixing point, they appear to need equal force, it is not so that one of them rotates more easily as far as I can feel.
But, of course, if the rubber 'stopper' onto which the arms rest when folded or one of the feet on the bottom cover is a bit thicker than the other that will results in the situation I have here.

 

[Cymruflyer]

Well, here the left arm does touch the ground, but I don't know if that was like that before. Never payed attention to it. I hope this is not a sign of something being wrong. When I turn both rear arms beyond the fixing point, they appear to need equal force, it is not so that one of them rotates more easily as far as I can feel.
But, of course, if the rubber 'stopper' onto which the arms rest when folded or one of the feet on the bottom cover is a bit thicker than the other that will results in the situation I have here.

However, since they should all be manufactured to the same tolerances, then they should all operate the same. If yours is different, then it may have been damaged.

 

[Ronny St.]

I did a thorough inspection of the 4 legs. It turned out that the left rear leg can be 'forced' to go a little bit further upwards by compressing the rubber damper (see picture in #24), while this can't be done with the right rear arm. So if I 'play' a little bit with that the 2 rear legs come a little bit above the horizontal surface, exactly as described by Yorkshire_Pud in #28:



Could that be an indication that there is something wrong with he rear left arm that caused the incident? Or shouldn't I worry about that?
I didn't fly since the test flight following the crash, but I hope to get this resolved and be confident in sending my bird into the skies

 

[slup]

...Could that be an indication that there is something wrong with he rear left arm that caused the incident?

No... nothing happened suddenly on the REAR left at the time of the incident... the FRONT left was first affected according to how the drone moved. It's clear that the front left lost thrust due to some reason when looking into the .TXT log & the .DAT log indicate further (through the accelerometer data included there) that the drone either collided with something or that something flew into it (a bird?).

If something is wrong now with the rear left, it most probably got damaged from the later crash.

 

[Ronny St.]

No... nothing happened suddenly on the REAR left at the time of the incident... the FRONT left was first affected according to how the drone moved. It's clear that the front left lost thrust due to some reason when looking into the .TXT log & the .DAT log indicate further (through the accelerometer data included there) that the drone either collided with something or that something flew into it (a bird?).

If something is wrong now with the rear left, it most probably got damaged from the later crash.

You are 100% right, slup.
Do you think I have to do something with the rear left leg to 'fix' it? It gets into place in an normal way, the only remark I can make is that it now has more movability upwards then before, but only when extra manual 'force' is applied on it and I even don't know if that was already the case before the crash.
Just wonna be sure I can launch my drone again without doing something really stupid.

 

[slup]

Anything that can flex (more than normal or intended) will probably increase the wear on the joint & over time increase the flex. The forces on the arms aren't constant... when ascending the arms will be forced upwards & when letting off from the throttle they will return back... very hard to predict if something will wear out in the long run or if it will cause something catastrophic in flight.

Make some test hovers & see if some excessive vibrations is created & showing up as a "jello effect" in the video recording or live view. You can also hover low so you can hold each arm & feel if you notice more or less vibration from either arm.

 

[Yorkshire_Pud]

When I first detected the rear arm problem with the drone in my first post it was due to my noticing that the rear left arm would lift/rotate-upward when I increased the throttle.
I do not accurately remember if this was in an eye-level hover and I commanded a climb but I do seem to remember it being visible when the drone was on the ground and throttle was given.
I have not yet checked the M2P of post #28 via the same method, I think I discovered its rotation whilst fiddling with the drone.
I have not dismantled an actual rear pivot but I would guess that their springing action is due to some form of cam-and-spring inside the actual pivot. I have dismantled and reassembled a front pivot and their springing action IS DUE to a cam-and-spring inside the pivot. With a broken off lug on a rear arm the presumed cam-and-spring is strong enough to hold the rear arm in the normal flying position when the prop is not producing a 'lot' of thrust but not strong enough to hold the arm in the normal position when the prop is producing climb thrust.
If you see movement/rotation when throttling up I fear you have a broken lug on the rear left arm.

 

[BudWalker]

No... nothing happened suddenly on the REAR left at the time of the incident... the FRONT left was first affected according to how the drone moved. It's clear that the front left lost thrust due to some reason when looking into the .TXT log & the .DAT log indicate further (through the accelerometer data included there) that the drone either collided with something or that something flew into it (a bird?).

If something is wrong now with the rear left, it most probably got damaged from the later crash.

There is something really odd about this one. When looking at the commanded, current and speed of the left front motor it appears to have lost the prop. And the time integrated gyro data for the first second there is pitching down, rolling CCW and rotating CW - all consistent with left front loss of propulsion.

But, then the MP2P starts rotating CCW while continuing to pitching down and rolling CCW. How is this even possible?

 

[Yorkshire_Pud]

Given the tilt I think I see in the photo of post #15 I am sorry to say I would also suggest you check the front pivots for bent pins on their tops. The front pivots are quite easy to check and do not need significant dismantling to do so, it's probably a 5 minute job for an experienced repairer but longer for us DIY'ers.

 

[Yorkshire_Pud]

There is something really odd about this one.

Did I miss the OP posting a DAT? If so where is it please?

 

[BudWalker]

Did I miss the OP posting a DAT? If so where is it please?

#16

I was very, very lucky ... (birdstrike?) on Mavic 2 Pro

 

[Yorkshire_Pud]

Thanks