And my Iris+ just went away...

Sad day. After good trials with original battery, very easy loiter mode, stable, gentle landing... real pleasure.

Today I changed to spare battery (Turnigy Multistar 5200 mAh 3S 11.1V). Switch on, proper blanking green, but as soon as I give some throttle the Iris jumped approx 20m in the air and started to run straight like crazy. Impossible to follow. Lost.

Do you think only the battery change could have done that ?

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • Happy end !

    I finally found my Iris this morning during my last hope walk. In fact, hit a tree, fallen on the grassy ground, battery disconnected and ejected nearby (how is this possible ?). And absolutely no damage ! A propeller gently bend, not broken, easy to repair.

    Back home, test connection : all is ok. Change battery, test stationnary flight (with telemetry on this time) : ok.

    It seems that guys here are building robust machines. Thanks 3DR !

    And thanks to everybody for the valuable advices.



  • Your description of the incident is exactly what would happen if you had the Iris in "auto" mode when you took off.

    If you are in auto mode this is the sequence that things occur

    1) Arm the Iris

    2) increase the throttle

    3) the copter will immediately rise to the altitude that is preset into the last auto mission that was downloaded to the Pixhawk.

    4) the copter will then try to fly to the first waypoint in the auto mission no matter if that waypoint is 1000 miles away

    I always take off in stabilize and making sure I'm in stabilize is part of my pre-flight checklist. The reason it's in my checklist is that I have accidentally armed in auto mode and my bird did exactly as you have described. I immediately switched it to stabilize and got control of it though.

    I'm not saying that that this is what happened to you but your description accurately describes what would happen if you armed and took off in auto and first waypoint is not near the coordinate you armed at.

    Sorry for your loss. I also have a sticker on my copters with my phone number on it so if someone finds it they can give me a call. Never needed it so far but you never know.


    • Yes I am thinking like you. Something fired the auto mode and send it far away. I m sure TX switch was on LTR. Maybe a software issue ?

      I was trying first to launch Mission Planner, without success (no answer from software, frozen showing launchbox). Maybe some bad instructions were sent to the copter.

      But thanks to everybody for your advices. I am learning all this the hard way, but so far no one was injured. At least I hope ! I will check the local news tomorrow. But if you heard of this :

      I am not living close to a nuclear plant. It's not my drone !

    • Loiter is a bad mode to take off with since it also uses GPS coordinate referencing. If the GPS is malfunctioning or has very poor HDOP then you arm and take off in Loiter mode the copter will try to lock in on a GPS coordinate. If that GPS coordinate is different than the actual location problems could also occur.

      Always take off in stabilize. Hover for a little while to make sure that you have proper attitude control and then switch to Loiter or Auto. If things go bad from there then you quickly switch back to stabilize to take control.

      I personally never fly without a live Mavlink connection with Mission Planner or DroidPlanner. This way the copter is telling me exactly what mode it's in before I take off. I know this sounds like a lot of trouble but these aren't toys, they are flying robots. You probably already understand that.

      Good luck,


  • I had a similar incident caused because I did not correctly load a new mission and as soon as I switched to Auto it took off to find it's first incorrect way point which was over 100 miles away.   I am still not sure why the "firewalls' and fail safes did not work, but I did manage to find the Iris after a long hike.

    I check telemetry to see where it was going and where it was when I lost sight of it.   I then hiked there with both my controller and lap top.   I kept following a straight line, as close as I could, and eventually was able to get telemetry from the Iris which was upside down, 35 feet in elevation, disarmed, and about 1/4 mile away.  It will keep transmitting for a while since telemetry does not seem to take too much energy.  It took about 2 hours to find but thanks to my laptop and telemetry still being broadcast I was able to find it, my my GoPro, etc.  

    Afterwards and with great relief, it was fun to watch the Go Pro video of the flight.   I felt so stupid when I realized it was trying to follow the last mission, not this mission.   Needless to say I now transmit the new mission, clear it on my screen, and make sure the Iris transmits back to me the mission to double check the correct one is loaded.   

    FYI, good video of how to double check the right mission is loaded:

    Good luck!   I would not give up yet even if has been a few hours.

    • Thanks for your answers. I feel less guilty about my battery change.

      I was in loiter mode. As soon as the Iris start to move, i called for a RTL, without success. I then also expected an auto RTL when the radio link broke, but nothing happened.

      This event came 1 hour before night, and I had no telemetry. I was just planning to hover gently in the garden to test flight duration with a full charged battery. Sure I searched during this last hour. But in the flight direction, it is all about forest, valley and small farms (for those who know Pyrénées in France...).

    • Hi Pascal

      take a walk NOW with a charged tx even if you didnt have telemetry on and hook up telemetry on your tablet/laptop for that walk or drive.. the modems are sold configured so it will start coming in when in range ie the IRIS always xmits unless explicitly configured down... also the 2.4ghz TX will make an alert tone when the ASST rc protocol finds the RX it is linked to(its also a 2 way protocol and can get you in the ball park in heavy country) definitely attempt a line plot on google earth from where you were standing and the line it flew in.. start walking that line now with the TX before the 5200ma battery dies completely(the rx and telemetry will stay up sometime after the motors shutdown auto..

      dont give up and make sure your phone # is on the drone for sitreps like this..

      in addition IRIS+ has nav lights so if you have any form of starlight intensifier night vision then can also be seen this way more easily. Also good chance it hung up on a tree few km from the takeoff point at 20m altitude.


      ps best of luck.. my flyaway was fortunately on a large federal ag facility on a 3300ma battery mostly discharged.. I did find it by using the above tricks

    • I did what you said and drive a long way around the probable crash zone without any answer from TX or telemetry. Area is quite wild, with rough topography.

      Anyway, thanks for the tricks

  • No way a battery change would do that!

    What firmware were you using?

    Any chance that you were using the telemetry radios and could post up some TLogs?


This reply was deleted.