UPDATED! Studied, videos, My first flight/crash... and now I'm gun-shy to fly

[JakeRobinson]

So, I bought a used (uncrashed) M2Z with flymore and other accessories about 10 days ago. I resisted the urge to put on my "cowboy hat" and wing it (i know - poor pun) but instead, I watched many "how to" YT vids on how to fly the zoom. Read many articles about it... I paid attention to many settings - I followed along with a "primer" on all the settings to "your first flight."

lots of rain so it added to more research.

So, finally, got settings the way I thought would be safe - put drone in "beginners mode" and went out to my back deck. Put the landing pad out and set the Zoom on it... I set the "return home" location based on the landing pad. I then used the take off mode slider. It took off and hovered... I used the yaw to move around with the camera. I then went straight up... maybe 50 feet or so. (100' maximum for beginner's mode) I move the gimbal down to see me sitting on my porch swing.

Next, I went straight back down to maybe 20" above the deck. I then decided to use RTH and expected it to rise up to the maximum height then come straight back down and stop to then land. However, when I move the slider to RTH it immediately went horizontally AWAY from the deck (and house) and headed for a tree... it stopped and was barely nipping a limb from the tree. I tried to move it away and it did not respond. I then was able to start bringing it straight down from the limb - luckily is threaded down between a couple of other limbs and was "in the clear." I decided to just land it there, however, this drone was being flown by some otherworldly force... It then started coming back toward the landing zone and even tho obstacle avoidance was on it still collided with the deck rail... it flipped and landed hard on the ground may be a 7' drop... it cracked the landing gear just below the motor... blades were okay.

I have no idea how it started flying away from the flight path... since I NEVER veered off a vertical path it should have just went straight up then straight down from where I took off... now I'm really gunshy to do any more flying until I solve this mystery...

I have attached two photos... one is normal landing leg and the other shows damage... is this something I can purchase and replace? thanks!

Also, if there is a way to gather the flight logs and see what is happening I'd be grateful for instructions.

Cheers,

 

[Former Member]

You can purchase and replace it. I have done many, but you might need to purchase a whole arm just to get the landing leg off of it.

 

[Meta4]

It's a good idea to do your learning flights in a large, open area well away from trees and other obstacles.
When there's nothing to hit, it's very hard to get into trouble

Also, if there is a way to gather the flight logs and see what is happening I'd be grateful for instructions.

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

 

[JakeRobinson]

You can purchase and replace it. I have done many, but you might need to purchase a whole arm just to get the landing leg off of it.

thanks for that...
What does a new are typically go for?

 

[Former Member]

thanks for that...
What does a new are typically go for?

You can get the arms online for around $49 for an OEM DJI

That's the USA price.

If you go to install it and you need any help, just ask on the board and maybe ping me in your post. If you post your progress up here, other people will know how to fix it if they ever break it.

 

[JakeRobinson]

You can get the arms online for around $49 for an OEM DJI

That's the USA price.

If you go to install it and you need any help, just ask on the board and maybe ping me in your post. If you post your progress up here other people will know how to fix it if they ever break it.

I googled it and found several options on ebay for around $36 to $40 + shipping (approx $10) I may do a video of repair and post it... I do know how to solder... thanks for the info!

 

[Simmo]

 

[Rackminster]

By no means am I an experienced flier - I've only ordered my Mavic 2 Zoom and taken a day-long drone class ... but the scenario you described sounded just like what our instructor repeatedly told us about.

His pre-flight checklist was this:

1. Controller on. Verify GPS on the controller, battery, etc.
2. Drone battery on. Wait for it to self-check and establish Home where it sits.
3. Check to make sure the drone has good GPS signaling.
4. Check other settings on the controller - signal strength to controller, battery levels, etc.
5. Engines on. Announce prior to taking off.
6. Liftoff. Announce prior to taking off.

He repeatedly stressed that "Fly-Away" moments are most likely caused by:

1. Bad GPS signals - if the GPS signal strength isn't strong enough (you'll see the number of satellites you're in contact with on DJI GO software on the screen) then the drone can't automate.
2. If the Drone can't find the controller for some reason, depending on its settings, it may try and return to Home, or it may hover, or it may land.
3. Home that hasn't been set properly - making the drone attempt to fly back to its last Home - even if that's somewhere in China.

 

[Meta4]

He repeatedly stressed that "Fly-Away" moments are most likely caused by:

1. Bad GPS signals - if the GPS signal strength isn't strong enough (you'll see the number of satellites you're in contact with on DJI GO software on the screen) then the drone can't automate.
2. If the Drone can't find the controller for some reason, depending on its settings, it may try and return to Home, or it may hover, or it may land.
3. Home that hasn't been set properly - making the drone attempt to fly back to its last Home - even if that's somewhere in China.

You would hope an instructor had a better understanding of his subject matter.
He is quite confused.

1. Bad GPS signals? Poor GPS signals does not cause the drone to "fly away"
At worst it could leave the drone in atti mode, still completely controllable but subject to drift with the breeze.

3. Home not set properly?
It's impossible to set the home point incorrectly.
Your drone will automatically set a home point as soon as it gets a good GPS location.
If you launched before a home position is set, it will still set a home point as soon as it gets a good GPS location, and that is going to be fairly close to the launch point.
It will NEVER go back to a previous home point as they disappear when the drone is powered off.
When you turn it on again, it has no home point until it gets GPS again and records a new home point.

 

[Rackminster]

Well, that's disheartening then. It was an expensive class, and I assumed he was a pro with these things.

He was a pilot, drone pilot, and worked with the police - and seemed to know what he was talking about. He was ADAMANT that our drones would try to return to a previous Home if we didn't set it each time. I mean, he drilled that in. Over and over.

His class was entirely focused on DJI Phantom and Inspire drones, using the DJI Go software.

I'll have to pull together some research and be sure to send the right info to DartDrones so they can have their instructors conveying accurate info and not giving people false data.

 

[JakeRobinson]

View attachment 65736

None of this applies to this situation - I had put a maximum height of 213 feet and then went straight up and straight down never changing trajectory off of The Landing Pad vertical axis as well as operating in beginner's mode so something else was going on. But thanks for posting the info

 

[sar104]

Well, that's disheartening then. It was an expensive class, and I assumed he was a pro with these things.

He was a pilot, drone pilot, and worked with the police - and seemed to know what he was talking about. He was ADAMANT that our drones would try to return to a previous Home if we didn't set it each time. I mean, he drilled that in. Over and over.

His class was entirely focused on DJI Phantom and Inspire drones, using the DJI Go software.

I'll have to pull together some research and be sure to send the right info to DartDrones so they can have their instructors conveying accurate info and not giving people false data.

Unfortunately these are quite complex devices when you factor in all the flight modes and failsafe behaviors. There are plenty of otherwise competent pilots who do not understand all aspects of the aircraft programming, and that is exacerbated by the amount of incorrect information that you can find posted on the various discussion forums, YouTube videos etc..

 

[JakeRobinson]

By no means am I an experienced flier - I've only ordered my Mavic 2 Zoom and taken a day-long drone class ... but the scenario you described sounded just like what our instructor repeatedly told us about.

His pre-flight checklist was this:

1. Controller on. Verify GPS on the controller, battery, etc.
2. Drone battery on. Wait for it to self-check and establish Home where it sits.
3. Check to make sure the drone has good GPS signaling.
4. Check other settings on the controller - signal strength to controller, battery levels, etc.
5. Engines on. Announce prior to taking off.
6. Liftoff. Announce prior to taking off.

He repeatedly stressed that "Fly-Away" moments are most likely caused by:

1. Bad GPS signals - if the GPS signal strength isn't strong enough (you'll see the number of satellites you're in contact with on DJI GO software on the screen) then the drone can't automate.
2. If the Drone can't find the controller for some reason, depending on its settings, it may try and return to Home, or it may hover, or it may land.
3. Home that hasn't been set properly - making the drone attempt to fly back to its last Home - even if that's somewhere in China.

Thanks for that. I actually had 13 satellites when the Drone was sitting in my living room just in side from the deck. I can't say I checked tho once I went outside but I did see RTH based on drone location sitting on the landing pad.

Is there a "GPS calibration?" I'm starting to wonder if it was off

 

[sar104]

Thanks for that. I actually had 13 satellites when the Drone was sitting in my living room just in side from the deck. I can't say I checked tho once I went outside but I did see RTH based on drone location sitting on the landing pad.

Is there a "GPS calibration?" I'm starting to wonder if it was off

You cannot calibrate the GPS. If you want to know what happened, rather than just making wild guesses, follow the instructions in post #3.

 

[JakeRobinson]

I appreciate everyone's contributions here. I have not been able to sit down and download the flight logs. I will do that and post them back.

 

[jwt873]

The flight logs will provide the best account as to what happened..

Just as a point of interest.... It's possible for GPS signals to be inaccurate. The phrase 'inaccurate GPS signals' might be better than saying 'bad GPS signals'. There are many things that can throw the signal out of whack: GPS Accuracy: HDOP, PDOP, GDOP, Multipath & the Atmosphere - GIS Geography

When the Mavic GPS takes its home point fix, it is possible for that fix to be several meters from the actual point on the earth where it took off from. When in flight, the GPS signals from the satellites that are being received can change becoming more or less accurate.

If you get a fix on takeoff that is 4 meters off and during flight the GPS satellite signal accuracy improves to less than one meter, then it will appear to the Mavic that the home point has moved by 3 meters. This could cause the drone to move in a direction other than what is expected.

This happens very rarely. Most of the time, the GPS will be less than one meter out. (This has been my experience).

I think that because of this, it's easy to assume that the GPS signals recieved are 100% accurate at all times during the flight and cannot ever be wrong. But as in the link I posted above, this doesn't always hold true.

 

[ff22]

Thanks for that. I actually had 13 satellites when the Drone was sitting in my living room just in side from the deck. I can't say I checked tho once I went outside but I did see RTH based on drone location sitting on the landing pad.

Is there a "GPS calibration?" I'm starting to wonder if it was off

Actually, RTH does not get "locked in" until the drone takes off straight up about 25 feet. It memorizes (photo like) its landing area if there are sufficient discernible patterns (all lawn or all asphalt does not provide the definition it needs). Deck planking might be insufficient. Too close to the wall of the home might throw it off, too.

 

[Simmo]

Actually, RTH does not get "locked in" until the drone takes off straight up about 25 feet. It memorizes (photo like) its landing area if there are sufficient discernible patterns (all lawn or all asphalt does not provide the definition it needs). Deck planking might be insufficient. Too close to the wall of the home might throw it off, too.

Home point can/is normally recorded on the ground, as soon as GPS Health allows it.
You are talking about 'Precision takeoff/landing' during RTH.

 

[Meta4]

Well, that's disheartening then. It was an expensive class, and I assumed he was a pro with these things.

He was a pilot, drone pilot, and worked with the police - and seemed to know what he was talking about. He was ADAMANT that our drones would try to return to a previous Home if we didn't set it each time.

That instructor is just spreading myths that were common back before DJI released the P3 series in early 2015.
Once DJI drones were using the DJI Go app and recording flight data, we've been able to see what actually happens under the hood and get a much better understanding of how DJI drones do what they do and find the causes of many flight incidents.

It would be much better if an instructor understood what he was teaching rather than just repeating what he's picked up from dubious sources.
Particularly when those myths have been busted four years ago.

I'll have to pull together some research and be sure to send the right info to DartDrones so they can have their instructors conveying accurate info and not giving people false data.

I've done the research already.
Here is an explanation: Help with lost Phantom 4 Pr0 V2

 

[sar104]

That instructor is just spreading myths that were common back before DJI released the P3 series in early 2015.
Once DJI drones were using the DJI Go app and recording flight data, we've been able to see what actually happens under the hood and get a much better understanding of how DJI drones do what they do and find the causes of many flight incidents.

It would be much better if an instructor understood what he was teaching rather than just repeating what he's picked up from dubious sources.
Particularly when those myths have been busted four years ago.


I've done the research already.
Here is an explanation: Help with lost Phantom 4 Pr0 V2

I went back and read your comments in that thread. In relation to the aircraft taking off and holding position with the mode switch in ATTI, what is happening with the more recent firmware is that manual takeoff is actually "Assisted Takeoff" and is a P-mode. Until the aircraft has launched and exited the assisted takeoff mode, flycState 10, it will continue to hold position. Once it exits it should go to flycState 0 (ATTI) rather than flycState 6 (P-GPS).