Analysis Request

[msteele]

Any chance for someone to determine if anything occurred that I could have avoided?

Here is the link to my log.

P-GPS mode
No abrupt flight control movements
Noted high-pitch prop noise for about 1 second before drone disconnected.
Drone dropped from ~210'-240' AGL

Thanks.
I'll respond to any further questions ASAP.

 

[sar104]

Any chance for someone to determine if anything occurred that I could have avoided?

Here is the link to my log.

P-GPS mode
No abrupt flight control movements
Noted high-pitch prop noise for about 1 second before drone disconnected.
Drone dropped from ~210'-240' AGL

Thanks.
I'll respond to any further questions ASAP.

Did you recover the drone? If so the DAT file would be really useful. At first glance the txt log doesn't show much of a problem other than one strange and possibly purely coincidental warning (warnings:Remote Controller Right Dial Locked. Lightly press it to adjust.) at 311 seconds. That's the second time this week I've seen that unusual warning precede a sudden disconnect and loss of aircraft.

 

[sar104]

Battery was good, signal strength was good, aircraft was responding appropriately to commands right up to disconnect. Definitely need the DAT file if available.

 

[msteele]

Sorry, please remind me the location of the file you are needing?

PS: yes, I recovered the drone. It dropped into a tree with significant damage. It may have hit the lip of the parking garage on it's way down.

 

[sar104]

Sorry, please remind me the location of the file you are needing?

PS: yes, I recovered the drone. It dropped into a tree with significant damage. It may have hit the lip of the parking garage on it's way down.

Instructions: How to retrieve a V3 .DAT File

 

[sar104]

That does depend on being able to power it up, unfortunately.

 

[msteele]

How's this?

Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-10-12_19-50-01.DAT

EDIT: Probably wrong file. Let me know.

EDIT 2:
For reference, here is the last frame of the video on my controller. I'm unable to see the relevant file on the SD card.

Drone POV is pointed at Home Point located in far parking lot near Ford Explorer with caution lights on top.

IMG_0025

• msteele
• Oct 12, 2017

Last frame of crash video

 

[sar104]

OK - that's not the correct file. Your flight time shows as 1:17 pm, while this DAT file refers to a power up at 2:13 pm. Look for the previous one.

 

[msteele]

This is a listing of the data files.
There may be a discrepancy due to a time zone change, maybe? That doesn't seem likely, however. But this is right on the border of the CST and EST.

Index

• msteele
• Oct 12, 2017

file index

I'm going to try to add the remaining files.

 

[sar104]

This is a listing of the data files.
There may be a discrepancy due to a time zone change, maybe? That doesn't seem likely, however. But this is right on the border of the CST and EST.

Index

• msteele
• Oct 12, 2017

file index

I'm going to try to add the remaining files.

Then I would guess one of the last two, but I'm not certain. How many times did you power up the aircraft after the crash?

 

[msteele]

Maybe 3-4 times, now. I've exported all files stamped in that time frame. I do not have an option to not choose the vid files, either, so it seems the exports are exceedingly large. The UI must have changed since that guide was written.

I'm concerned I am frustrating you. My apologies.


DJI_ASSISTANT_EXPORT_FILE_2017-10-12_22-53-41.DAT

 

[sar104]

Maybe 3-4 times, now. I've exported all files stamped in that time frame. I do not have an option to not choose the vid files, either, so it seems the exports are exceedingly large. The UI must have changed since that guide was written.

I'm concerned I am frustrating you. My apologies.


DJI_ASSISTANT_EXPORT_FILE_2017-10-12_22-53-41.DAT

No worries. There is no simple way to identify the right files. Standby.

 

[sar104]

That had the correct file. The cause of the shutdown was sudden power failure. The motor voltage fell from 15 V to around 7 V in around 80 ms. At that point the FC shut down and no further data are recorded. Was the battery in the aircraft when you found it?

 

[msteele]

The battery was at the tree base. It may have popped out when it collided with the tree or concrete structure next to the tree. Perhaps it was not seated all the way? The battery seems fine, however, as this is the one I've used to power the bird up for the data extractions.

Thanks for your time. I was not sure if it was a power failure, but you've shown it to be the case.

Again, thanks!

 

[sar104]

The battery was at the tree base. It may have popped out when it collided with the tree or concrete structure next to the tree. Perhaps it was not seated all the way? The battery seems fine, however. As this is the one I've used to power the bird up for the data extractions.

At the time of the incident the aircraft was flying backwards at 10 m/s and pitched nose up at 15 - 20°. If the battery were not properly seated then that is the most likely flight condition to cause it to disconnect. It is a plausible explanation.

 

[sar104]

When you power it up will the motors start?

 

[msteele]

Yep, trying to get that 'reverse reveal shot' of the smoke stacks.
Just tested the motors. They run.

 

[sar104]

Yep, trying to get that 'reverse reveal shot' of the smoke stacks.
Just tested the motors. They run.

Then my guess would be an unseated battery. The Phantom battery clips have always seemed less positive than I would like. The Mavic feels much more secure.

 

[msteele]

Update:
DJI repaired the bird under warranty with zero out of pocket cost, and I received it in the mail yesterday via UPS. Flew it today. Checked the battery snap at least 15 times before I took off. I may mod it to include an external safety harness - possibly velcro strips.