Low battery critical return to home, almost hit trees over creek

[Joe Blow]

I have about 10 days and 5 battery charges on my new MA2 and everything was going OK. Close quarters around house and trees, wires, swimming pool, motor home, trucks, close calls but OK. I practiced some RTH's before I knew to go straight up 40ft? to set a good RTM point. It was coming in off a little and I found out the joy sticks would over ride the RTM so I could make corrections.
OK so today the battery was low, I had the MA2 just over the edge of the bank teasing my boxer that couldn't reach it and got low battery warning. OK no big deal It's only 20ft away from home when it started a count down to RTH. It started to climb with tree branches 7ft over it and the creek 6ft below. I tried to correct it but all I could do was hold the stick to keep it from climbing but got no response from the other stick and it still wanting to climb into the branches and fall into the creek.
I tried to cancel RTH and got no response, mean while it's squawking and counting down, and my life flashed before my eyes. I've been having some trouble lately my fingers dry not working to good on the smart phone.
Anyway I pushed the switch to SPORT mode and regained control after it went wild because I had the sticks going all over the place. I brought it over and landed with 10 sec on the clock.
I was thinking I was going to break an ankle or leg jumping 7ft down the steep bank to the rocks in the creek to grab my $1200 bird out of the water. I'm learning. I didn't like that it wouldn't let me bring it 5ft back to land it in the yard let alone 20ft to the Home point.

 

[DanMan32]

You shouldn't have to go straight up 40ft to set home point, though if MA supports precision landing, then going straight up around 20ft will improve landing right at the HP. PL uses the downward sensors to take a picture as it takes off, then matches that image as it lands.

I'm surprised it went up on RTH if you were only 20ft from HP. Usually Mavics land in place rather than return to home point when you are that close to HP.

You should be able to cancel RTH right from the remote itself. Just press and hold the RTH button until it cancels.
If it was counting down, then it shouldn't have been in RTH yet until countdown reached 0. At least that's how it is with other Mavics.

 

[Meta4]

It was coming in off a little and I found out the joy sticks would over ride the RTM so I could make corrections.

You can get into trouble fighting against an automated flight mode like the RTH or its autolanding.
It's always a much better idea to cancel the automated flight mode and resume control properly.
If you leave the automated flight mode on, it will continue trying to do what it's programmed to and the outcome might not be pretty.

 

[ven]

Glad you managed to save it, wow thats too close! Interesting how sport over rid and allowed you to control. Thats one for me to remember if(or when)it happens to me!

 

[Dakarenduro]

How low was the battery when this occured?

Just wondering. Good idea is to avoid a low battery situation, both for battery longevity and running into automated landing situations. Not saying that was the case here specifically but in general.

Yeah, the other Mavics would have auto landed at that spot, being only 20ft from the Home Point. Maybe the Air2 does it differently. Test it out in a field and see what happens.

Glad you saved it!

 

[Greekislandlover]

Glad you got the drone back ok

I'd probably have another look at the instructions on how the drone is supposed behave at various levels of battery depletion. It doesn't "Just" return to home. Depending on just how depleted it is it will behave differently and give you different options. The manual states on page 14 that if the battery gets so low it's only got enough power to descend from altitude that's what it will do. You can't cancel it but you can use the sticks to move it during the landing process.

This rather suggests that you are using the battery to get the absolute max flying time out of it, and cutting when the drone has to land to the absolute last second. Personally, I have cut when the low battery warnings come in to 20% and when it says low battery that means playtime over.

Toggling the switch to change modes has been another of the ways to cancel certain actions and programs, but it should respond to the red X button unless it's programmed to ignore it as it would do in this situation. DJI have thought very carefully about trying to stop your expensive drone from destroying itself, and to some extent stopping you from doing the same.

It's always worth looking at tutorials on autolanding. I remember an incident with my DJI spark when it decided to return to home and wouldn't cancel. I was just feet away and the plan was to manually land it. However, it decided to go up to the RTH height and buzz off into the distance to whence it took off from, leaving me to chase through a field. I actually read the manual at that point!

 

[Joe Blow]

I did read the RTH modes and a lot of the manual but, I'm not as quick as I used to be and don't absorb the information like I used to. (In other words you might not want me piloting your airplane in an emergency) (By the way I have a pilots license and owned two airplanes that I was smart enough to sell 10 yrs ago)


I just went back to refresh some of what I read in the manual. Here are a few copy/paste excerpts



It is recommended to discharge the Intelligent Flight Batteries to 30% or lower. This can be done by flying the aircraft outdoors until there is less than 30% charge left.


FAIL SAFE RTH
During RTH, the speed and altitude of the aircraft can be controlled using the remote controller or DJI Fly if the remote controller signal is normal. The orientation of the aircraft and the direction of flight, however, cannot be controlled.