Iris+ Random Crash In Flight - Lost In Water

Hey DIY Drones,

This is my first post here, but I felt I would share my story and log with the community. Today I was out for a rather routine flight of my Iris+ from 3DRobotics that included an Auto Flight followed by some manual flight in Loiter mode directly after. No heavy wind or outside weather factors to worry about. A nice 70 degree evening here in St. Pete, Florida. Normally I fly the Iris+ with the Tarrot 2D gimbal and a GoPro but thankfully today I did not. I was getting my flight plan ready for a filming I was planning next week and was getting down the flightpath before mapping out the angles of the shots.

After flying in auto mode for the duration of my flight plan, I took over in loiter mode to do a short flight around a fountain I planned to shoot. I had just had the aircraft fly the same path in auto mode and I like to practice my flights manually incase I have to assume control in the middle of a shoot. About halfway through the maneuver the Iris+ started to wobble and descend like it was losing power suddenly. I kicked the throttle to full power and directed the drone away from the water (knowing a crash was almost imminent) but the drone failed to react to the controls and crashed in the lake I was flying over. About 20 feet from shore too. *Insert sad face* The drone now sits at the bottom of the lake in about 10 feet of water. I was unable to recover the aircraft today but and hoping to in the morning. 

Attached is a link to the log of the flight. So far looking at the data I cannot see anything to explain the sudden loss of control. The only thing I have really notice was a drop in battery voltage at the end of the flight, but I am unable to tell if this is because of the loss of the aircraft or there really was a sudden loss of battery voltage. The HUD never told me I had less than 70% battery during the flight and even so a loss of battery should have caused a return to launch. 

If anyone out there has idea what might have caused this crash, I'll take any input. With all luck I will recover the aircraft in the morning, but with the craft sitting in 10 feet of water for around 18 hours I am assuming a total loss. Sad. This craft seemed so stable in all other flights I've done with it (30+) and it was becoming a workhorse for me. 

Thanks to any who help! 



2015-03-28 19-09-14.tlog

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  • Bummer dude, I had a heavy landing because of voltage drop off, I was pushing the limits and had lowered my RTL battery failsafe level too far. Fortunately I learnt my lesson without any loss or damage except for pushing the voltage too low on the battery. That battery is now toast!

  • I'm sorry to hear of your loss, my Cinetank landed in a river after a 200m fall. I got lucky as the battery was ejected when it hit the water. I lost one ESC and a couple props, but that was it.

    As for the cause of your crash, you said something that called my attention "The HUD never told me I had less than 70% battery during the flight and even so a loss of battery should have caused a return to launch". Arducopter assumes that you have 100% battery at the start of a flight, regardless of whether you do or not. A much better gauge is to check the voltage levels.

    You can verify this behavior easily enough.. go for a fly with a full battery and the land. Unplug the battery and plug it back in. It will read 100%.

    • Wow in all my reading I never knew this! That is for sure useful info to remember next time!

  • Hi there.

    If you don't already use one, I suggest you use a low voltage battery alarm like this one in the link

    Redundancy for battery is an excellent idea and the loud beeping pretty much screams at you to land immediately.

    Cheers, Steve

    • For most other multirotor this is an excellent idea. For the IRIS + the battery is a very tight fit in the battery enclosure and that would certainly not fit. 

  • One other thing I do now is I stopped swapping batteries. They do wear out and loose capacity. Instead I leave the same battery in my quad and charge it over and over. You will start to notice a drop off in air time [ I have telemetry now ]. After it's less than you are used to by 3-4 minutes recycle it. Get a new one. It's much easier to remember your battery cycle that way. Another idea I did was number them. If you start to think you notice one dropping off write a ? on it. I would guess %50 of crashes are because of this. It's one of the reasons DJI has a limit to how many times you can fly on one battery. I think this is bs and makes them a lot of money but there is some rational to it. 

  • I had a crash once because I simply got my batteries mixed up. I thought I grabbed a  charged one and instead grabbed one that wasn't completely out but wasn't ready for  action either. I also didn't fire up my ground station. You know how it is.... Sometimes you don't want to mess with that. 

    Since that crash I bought very very small green rubber bands. They are about 1/2" around. Got them at the dollar store. The second my batteries come off the charger they get this little green rubber band around the lead. The second I put it on my quad it comes off. Sometimes it really isn't a bad idea to rely on good old fashion 'analog' technology. :] 

  • I had a similar experience with slightly less drastic results.

    Turned out to be another bad battery.

    My second since my purchase back in November.

    I know you can't test it anymore, but was your battery by any chance a 5100 purchased from USR around the same time?

  • Justin.  Did you recover your Iris from the water?

  • Sorry to hear about your crash...  This can be a very frustrating hobby... checked your log and if the battery and current telemetry checks out (no reason to say it doesn't) then the crash for caused by not enough power to keep the IRIS in the air. 

    When you say that the battery was fully charged, what are you doing to check that ?  do you have a separate battery health meter ? if not get one.  Anytime that you are flying over something like water I would give yourself a big margin and change the battery failsafe to something a lot higher etc

    This did not cause the crash, but you did not have a very good GPS lock for a while at the beginning... something to look at there

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