So had my first crash, but not really my fault...

Mechcondrid · Jan 23, 2018

so had brought out my Mavic to do some filming for a local Milsim airsoft event; was working great until i brought it inside for the indoor filming (old steel mill warehouses with 40+ foot ceilings and open floor plan for the most part). as expected it went into attitude mode which was fine, perfectly comfortable in att mode as the first RC models i learned on were non-stabilized 450 size collective pitch helis.

so about 5 minutes in i start actually getting a gps lock through the corrugated steel roofing of the warehouse (no idea how) but never got any compass errors (stayed away from walls and just panned for shots) but when it would get the periodic gps locks and try to kick into gps flight mode it would completely ignore any and all control inputs, to the point of drifting or proceeding with whatever movement it was currently in until it lost gps lock or resolved its position (im assuming) and then it would realise "oh hey hes telling me to do something" and then jerk back to my commanded attitude input.

so my question is: is this normal or did my mavic have a brain fart and decide to be "special"?

damage was pretty minimal as i was able to get control at last second and kick it into sport and reverse the travel direction enough to soften the impact: lost the rotor blades, cracked the back left arm's mounting hole on the middle frame (motor and arm wiring all intact and the arm itself appears undamaged, the hex bolt just pulled through the side of the screw hole on the middle frame) and the ribbon cable for the camera ripped on the last connector leg as the impact jarred the gimbal stabilizer plate off the guide and pulled 3 of the gaskets out of the mounting holes (kept the gimbal cover on just in case; good thing i did)

so all in all about $40 to $60 worth of parts to fix.

Former Member · Jan 23, 2018

Got some pictures?

glnelso · Jan 24, 2018

My guess is, it was working as designed. That’s a great question. And a good story. You put me right in the room. Sorry about the damage.

Mechcondrid · Jan 24, 2018

Thunderdrones said:
Got some pictures?

Not at the moment can take some though
its not bad considering it froze at probably a 8 or 10 degree attitude and kept accelerating because of it
lucky I altered sport mode to the sport mode+ specs or I wouldn't have been able to soften the blow at all

Former Member · Jan 24, 2018

Mechcondrid said:
Not at the moment can take some though
its not bad considering it froze at probably a 8 or 10 degree attitude and kept accelerating because of it
lucky I altered sport mode to the sport mode+ specs or I wouldn't have been able to soften the blow at all

Quick thinking.

Qoncussion · Jan 24, 2018

I have read enough posts here to gather that the biggest problem with flying a Mavic indoors is exactly what you described. ATTI mode is exactly what you want in that situation. If you do get a minimal number of GPS locks mid-flight, the GPS signals are most likely coming from/through a window, or other opening, from a single direction. Which means that it does a very poor job of triangulating the Mavic's location in 3D space. As such, the Mavic corrects its position (which was wrong to begin with) to a new location. During which time, it gains or loses satellite locks, and again corrects its course...etc.

I would say, instead of binding the sports mode switch to sports+, I know there is a way to have it trigger manual ATTI mode.

Mechcondrid · Jan 24, 2018

Qoncussion said:
I have read enough posts here to gather that the biggest problem with flying a Mavic indoors is exactly what you described. ATTI mode is exactly what you want in that situation. If you do get a minimal number of GPS locks mid-flight, the GPS signals are most likely coming from/through a window, or other opening, from a single direction. Which means that it does a very poor job of triangulating the Mavic's location in 3D space. As such, the Mavic corrects its position (which was wrong to begin with) to a new location. During which time, it gains or loses satellite locks, and again corrects its course...etc.

I would say, instead of binding the sports mode switch to sports+, I know there is a way to have it trigger manual ATTI mode.

Ya was going to explore binding one of the c switches to sports mode in the parameters menu of the dji assistant and have the sport switch be the atti mode switch or just selectively changing it when I know I might have to fly indoors

Or could always make the normal gps mode have the sport+ specs and put the control gain down a bit to feather the input a little to compensate.

BD0G · Jan 24, 2018

Or you could just tape a piece of tin foil over the top to block GPS reception and remove when not flying indoors.

Mechcondrid · Jan 24, 2018

BD0G said:
Or you could just tape a piece of tin foil over the top to block GPS reception and remove when not flying indoors.

honestly that looks like ****, and it's just easier to hook up my laptop that i always have with me anyway to clear off and backup the sdcard and just change the parameter and reboot.

BD0G · Jan 24, 2018

Are you concerned about LOOKS of your Mavic Pro while flying inside a building and trying to get reasonable video?

Mechcondrid · Jan 24, 2018

BD0G said:
Are you concerned about LOOKS of your Mavic Pro while flying inside a building and trying to get reasonable video?

yes because if people stop what they're doing to look at the shiny silver thing flying around that kinda ruins the shot somewhat, at least as far as these kinds of events go

colinfowler · Jan 24, 2018

Mechcondrid said:
yes because if people stop what they're doing to look at the shiny silver thing flying around that kinda ruins the shot somewhat, at least as far as these kinds of events go

so they wont notice the mavic flying around uncontrollably without the foil?

Mechcondrid · Jan 24, 2018

colinfowler said:
so they wont notice the mavic flying around uncontrollably without the foil?

i think your missing that if i just change the binding of the sport switch to engage atti mode that this is not what would happen; the reason it crashed is because it was getting a gps lock and coming out of atti mode and ignoring control input during that.
keeping it in control in atti mode isnt an issue, it was when it ignored my control input is what caused the crash.

sar104 · Jan 24, 2018

I'm not entirely convinced by the explanation that it is intermittent GPS reception causing the problem. I would suggest pulling the flight log or DAT file and checking to see exactly what was going on.

Mechcondrid · Feb 4, 2018

so replaced the back left arm and the gimbal ribbon cable, but i'm getting a weird error; a "battery status" error but when i go into the menus the battery is reporting normally and is showing the propper voltages.
it also shows good comms with the battery controller.
it does this with both the battery that was loaded during the crash and a spotless secondary battery.

no idea why it is showing this, it does not show in third party apps like litchi or precision flight.

the dji assistant for some reason shows that there is a 0.0v for the battery on the dashboard page even though the app shows it is in fact reporting the voltages...

BD0G · Feb 4, 2018

So during the crash one of the cables that connects to a subordinate PCB became loose? Internal PCB has a hairline crack that severed a trace? Just speculating.

Remove and reload DJIGO4 just for giggles.

Mechcondrid · Feb 5, 2018

well if the pcb or cables came loose then why would it report a voltage and cell voltages at all then?

i'll try reinstalling the app i guess since the dji app is the only one getting an error