I crashed, I have a question.

[Air Pug]

Hey guys! Long time lurker, first time poster. Long story short, I crashed my Mavic Pro yesterday - I took off from the spot I normally take off, which is between my house and the neighbor's house, which is ~15' wide. Made all the pre-flight checks and all looked good (sats, battery, no weird noises). MP took off fine manually and started quickly drifting off to its right side at about 10' elevation, I tried correcting it and was successful, but then happened again but unable to recover and it hit the side of the house, then dropped altitude to ~4' and hit the side of the house again while flying uncontrollably, then slammed into the rear of the house at which time I killed the propellers and dropped on grass from ~7'. Post-crash assessment shows that 3 propellers broke, clipped and scratched. There is minimal scraping along the battery and rear of the body, and there is a hairline crack on the rear plastic wing that extends past the leg support, which leads to believe that the rear leg took the impact. It does not move unless I place pressure on it, and the leg mechanism moves normal when taking it from folded <-> unfolded. All other legs/arms move fine with no play, motors turn without resistance manually and while powered on, gimbal works as expected, no problem with AF. After work I took it for a test flight with all new propellers and all works as expected - all controls respond like usual, although it was very windy in the evening when I tried the test, so it drifted and moved quite a bit...so I'm waiting for the wind to die down to try it again.
Overall the only damage looks to be the scrape on the battery and rear body, and the hairline crack on the rear leg support plastic wing. Soooooo my question is if it is worth having a professional inspect it? For full disclosure I bought this MP 2nd hand off a guy I know, who had it for 1 1/2 years before I did, so no DJI care or warranty is valid at this time, so all charges will be out of my pocket. I take care of my things, so if y'all think it's smart to have it checked out after this crash I will look into it, but from a test flight all looks normal .
Any advice or suggestions are much appreciated.
Thanks!

 

[RayOZ]

You should post the flight log of the incident and someone here might be able to figure out what happened.

 

[Former Member]

Whats your location and do you have any pictures?

 

[Deleted member 93449]

Cracks can propagate due to vibration or flexure. You don't want to be flying at 100' when a crack propagates just enough to cause an increase in vibration/flexure and worse case an out of control situation. Maybe someone can suggest an epoxy or glue that can be safely used on the body of the drone to help secure and reinforce where the crack is located.

 

[PhantomFandom]

Hey guys! Long time lurker, first time poster. Long story short, I crashed my Mavic Pro yesterday - I took off from the spot I normally take off, which is between my house and the neighbor's house, which is ~15' wide. Made all the pre-flight checks and all looked good (sats, battery, no weird noises). MP took off fine manually and started quickly drifting off to its right side at about 10' elevation, I tried correcting it and was successful, but then happened again but unable to recover and it hit the side of the house, then dropped altitude to ~4' and hit the side of the house again while flying uncontrollably, then slammed into the rear of the house at which time I killed the propellers and dropped on grass from ~7'.

No telling for sure what happened without the flight logs, but perhaps you did not have a GPS lock prior to takeoff? Taking off between two houses with only 15 feet between them sounds like a tough spot to get good satellite coverage. Did you get a GPS lock? Did it record the Home location? Did you get an indication that the MP switched to ATTI mode?

Overall the only damage looks to be the scrape on the battery and rear body, and the hairline crack on the rear leg support plastic wing.

I would have a look at any crack on the airframe and suggest getting it fixed. As to the internal circuitry, check the compass, IMU, and gimbal calibrations to make sure none of them pop up any issues.

 

[Mossiback]

... Made all the pre-flight checks and all looked good (sats, battery, no weird noises)...

Was it in GPS mode with a home point recorded? You can have satellites but not enough to get GPS lock or if you have the minimum (9 for my MP) you could lose one which will put you in Atti mode.

... MP took off fine manually and started quickly drifting off to its right side at about 10' elevation, I tried correcting it and was successful, but then happened again...
... For full disclosure I bought this MP 2nd hand off a guy I know, who had it for 1 1/2 years...

Sounds like a classic compass malfunction, caused by either metal around the launch site or a Mavic in need of degaussing. Your logs should indicate if this was the cause.

 

[Air Pug]

Thank you all for your suggestions.
To answer y'alls questions:
Prior to takeoff it did lock on to enough satellites for GPS mode, with home point recorded. I can't recall how many satellites it locked onto but it was within a safe number. In the few seconds that all this went down I don't recall receiving an ATTI mode warning. In regards to what the issue was, I think that the error was that it might have lost GPS signal after takeoff, or something screwed with the compass, although there isn't any noticeable metal around where I was normally launching it from. I haven't had a chance to retrieve any logs but I can do that and post when I have time.
I did calibrate the IMU, compass, and gimbal yesterday prior to the test flight, with no issues popping up. I also did put some super glue on the rear leg over the crack, hopefully to avoid any further splitting/cracking - we'll see if it holds up after some more testing, once the **** wind dies down!

 

[Air Pug]

Took the MP out for another test flight, this time I elevated to 350', then took it out 2000' away, without any problems. So far everything worked as expected, and the spot where the crack was is stable with the super glue, so at this time it doesn't seem like it needs any professional examinations.
I'll upload the flight log from the crash if anybody has any input or insight on what happened...I'd be interested in knowing what the issue was.
Thanks!

 

[julius13]

Hey guys! Long time lurker, first time poster. Long story short, I crashed my Mavic Pro yesterday - I took off from the spot I normally take off, which is between my house and the neighbor's house, which is ~15' wide. Made all the pre-flight checks and all looked good (sats, battery, no weird noises). MP took off fine manually and started quickly drifting off to its right side at about 10' elevation, I tried correcting it and was successful, but then happened again but unable to recover and it hit the side of the house, then dropped altitude to ~4' and hit the side of the house again while flying uncontrollably, then slammed into the rear of the house at which time I killed the propellers and dropped on grass from ~7'. Post-crash assessment shows that 3 propellers broke, clipped and scratched. There is minimal scraping along the battery and rear of the body, and there is a hairline crack on the rear plastic wing that extends past the leg support, which leads to believe that the rear leg took the impact. It does not move unless I place pressure on it, and the leg mechanism moves normal when taking it from folded <-> unfolded. All other legs/arms move fine with no play, motors turn without resistance manually and while powered on, gimbal works as expected, no problem with AF. After work I took it for a test flight with all new propellers and all works as expected - all controls respond like usual, although it was very windy in the evening when I tried the test, so it drifted and moved quite a bit...so I'm waiting for the wind to die down to try it again.
Overall the only damage looks to be the scrape on the battery and rear body, and the hairline crack on the rear leg support plastic wing. Soooooo my question is if it is worth having a professional inspect it? For full disclosure I bought this MP 2nd hand off a guy I know, who had it for 1 1/2 years before I did, so no DJI care or warranty is valid at this time, so all charges will be out of my pocket. I take care of my things, so if y'all think it's smart to have it checked out after this crash I will look into it, but from a test flight all looks normal .
Any advice or suggestions are much appreciated.
Thanks!

I concur with most responsible pilots here. Any crack is not good. Send it to Rob, Thunderdrones. He will assess it and likely replace the entire arm/wing. The chance of it cracking more if you don't do anything to it is 100% failure. You don't want that liability just because it looks OK. BTW...If you aint crashing, you aint flying, so don't beat yourself up over it. I know I did. I don't know anyone who hasn't crashed. It's occupational hazards.

 

[runeOfRune]

Did you hit anything at 15.6s?

At 11.75s roll stick was pushed left and rested on full left for approx. 100ms, then full right where it was held for 400ms. The drone reacted to those commands and then levelled out. 3 seconds later, IMU registered the drone tilted 90 degrees to the right without any stick input.

You had good GPS throughout the entire flight.

Can you upload the .dat?

 

[Jetadhai]

Took the MP out for another test flight, this time I elevated to 350', then took it out 2000' away, without any problems. So far everything worked as expected, and the spot where the crack was is stable with the super glue, so at this time it doesn't seem like it needs any professional examinations.
I'll upload the flight log from the crash if anybody has any input or insight on what happened...I'd be interested in knowing what the issue was.
Thanks!

How about some tape around the crack arm too ... I was going to say a few wraps of aluminium (metallic) tape but ... may affect compass ... there are other waterproof versions ... can’t think of one now ... not too confident with superglue with the temp extremes & vibration as it was laid over a contaminated profile ...

 

[Air Pug]

I concur with most responsible pilots here. Any crack is not good. Send it to Rob, Thunderdrones.
BTW...If you aint crashing, you aint flying, so don't beat yourself up over it. I know I did. I don't know anyone who hasn't crashed. It's occupational hazards.

Thanks for the info, and thanks for the words of wisdom. I did feel pretty crappy after the crash, but I gotta keep my chin up [ow! my chin!]

Did you hit anything at 15.6s?

At 11.75s roll stick was pushed left and rested on full left for approx. 100ms, then full right where it was held for 400ms. The drone reacted to those commands and then levelled out. 3 seconds later, IMU registered the drone tilted 90 degrees to the right without any stick input.

Can you upload the .dat?

Those inputs are from where I moved right (by mistake, since the drone was facing me) and then corrected to the left, where it moved away from the wall, but then again it drifted right and hit the wall at 15.6 and tilted 90 deg.
I can upload the .dat once I get home.

not too confident with superglue with the temp extremes & vibration as it was laid over a contaminated profile ...

We'll see how it holds up. I'll upload a pic when I get home to better see where the crack is.

 

[Air Pug]

Here are pics:
You can see the crack on the distal part of plastic lip of the left rear wing, and you can appreciate how there’s no physical separation, only that hairline crack running vertically. Thoughts?

 

[Steve R]

I have the exact same issue with my Mavic Pro.. Happened when I hit a tree. My solution is to cut a gusset from high strength Plexiglas, (1/16 " thick) cut to cover the entire surface, and laminate it on top of the cracked member. I'll be cutting a matching gusset for the other side to keep things in balance. The gussets will be bonded with high strength epoxy.

 

[Air Pug]

I have the exact same issue with my Mavic Pro.. Happened when I hit a tree. My solution is to cut a gusset from high strength Plexiglas, (1/16 " thick) cut to cover the entire surface, and laminate it on top of the cracked member. I'll be cutting a matching gusset for the other side to keep things in balance. The gussets will be bonded with high strength epoxy.

Please post pics once you get it done, I’ve been contemplating something similar for extra strength and stability.

 

[Steve R]

Please post pics once you get it done, I’ve been contemplating something similar for extra strength and stability.

I will... been taking my time with this, as I want it to not only be stronger than the original, but look professional as well. In my opinion this is probably the weakest part of the Mavic Pro, and is poorly designed. Looks to me to be part of the main structure, and not replaceable without replacing the entire "body" of the drone. My fracture is on the right rear arm.

 

[PhantomFandom]

As with any aircraft, there always is a delicate balance between structural integrity and weight. Sure the entire shell could be made out of stainless steel, but then we would need bigger motors and a bigger battery. That would in turn affect the size of the entire aircraft and you start a vicious cycle. Of course there is also the consideration of cost. Plastic could be substituted with carbon fiber or titanium but then the cost would put it out of reach of many people.

These drones are generally well built for the aerodynamic loads they incur during flight. Parts break when they are crashed, and I think that is to be expected.

 

[Flycaster]

Thank you all for your suggestions.
To answer y'alls questions:
Prior to takeoff it did lock on to enough satellites for GPS mode, with home point recorded. I can't recall how many satellites it locked onto but it was within a safe number. In the few seconds that all this went down I don't recall receiving an ATTI mode warning. In regards to what the issue was, I think that the error was that it might have lost GPS signal after takeoff, or something screwed with the compass, although there isn't any noticeable metal around where I was normally launching it from. I haven't had a chance to retrieve any logs but I can do that and post when I have time.
I did calibrate the IMU, compass, and gimbal yesterday prior to the test flight, with no issues popping up. I also did put some super glue on the rear leg over the crack, hopefully to avoid any further splitting/cracking - we'll see if it holds up after some more testing, once the **** wind dies down!

Did you hear the words:
"Homepoint has been updated, please check it on the map"???

Like mentioned above, looks like it lost GPS and went into ATTI mode......

 

[Steve R]

Air Pug... Here is the photo of the template I've made for my repair... Duplicate on each side. Cutting from 1/16 high strength plexi next

 

[runeOfRune]

Back arm w/motor is $50 max, replace it. Not worth risking flying with such DIY hacks. You can't guarantee it's going to hold.