IRIS Loiter Altitude Problem

Hi All,

I'm relatively new to the world of drones and the 3DR IRIS is my first drone. I can fly it well in stabilize mode, but use loiter mode fairly often when taking aerial video to keep better control. Recently though, loiter mode hasn't been working correctly. When loiter mode is engaged IRIS will sometimes drop a few feet and then hover and when I put the throttle all the way up IRIS climbs altitude fairly slowly (I'm talking about 1m every 15 seconds or so and will reach a "ceiling" at about 30m. The same holds true for descending. It changes altitude very slowly and didn't do this before. If I take it off loiter mode to stabilize I can climb no problem to about 300 ft. Engaging loiter at these heights have also resulted in about 5m drops and sometimes flips. 

Any help or suggestions would be great. I'm not sure if it is a software problem or hardware issue. I did have some "rough" landings but nothing my IRIS hasn't been through before. I tried re-installing the firmware and writing the proper params for my configuration just to make sure it was properly configured, but this didn't solve the issue. 

Thanks fellow drone lovers!

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

Join diydrones

Email me when people reply –


  • You are hitting a few "issues":

    will reach a "ceiling" at about 30m: This is a so-called fence functionality for security purposes and configurable. See here:

    climbs altitude fairly slowly (I'm talking about 1m every 15 seconds or so: This is the configurable climb sensitivity. See here:

    Engaging loiter at these heights have also resulted in about 5m drops and sometimes flips: Either you are not in mid-throttle position when switching from AltHold/Loiter to Stabilize or your mid throttle position is not correctly calibrated. See here:

    Are you flying with gimbal and tall legs? If so, don't. IRIS is to heavy / underpowered for that. 

    • Hi Christian, 

      So I just wanted to update you and let you know that the "ceiling" was indeed caused by the geo-fence functionality. I've played with the climb sensitivity and that did the trick as well. Do these parameters only effect loiter mode? 

      The unintended flips were also due to me not going to mid throttle :-). Rookie mistake on my part.

      So does updating the firmware as 3DR suggest wipe out these parameters? When it came from the factory it did not have the ceiling or the low climb sensitivity in loiter mode. 

    • The geo-fence kicks in in any flight node. The Climb sensitivity applies to every mode except Stabilize (for the standard IRIS modes). 

      Yes, keeping the throttle stick mid level is indeed important. :-) 
      That was also the cause of my only crash that I had so far (knock in wood).

      These parameters should not get lost when you upgrade firmware. But they might be overwritten when you go through the setup in Mission Planner or when you make manual changes. 
      My advice: Keep a saved copy of your parameters and compare frequently if your current copy still matches that. Mission Planner lets you do that automatically. 

    • I wouldn't say "don't" fly with gimbal and tall legs due to "IRIS is to heavy". Mine flies well with that set up. No problems with under power. IRIS holds loiter at half throttle and I have not found any difference in power towards the low battery level.

      Maybe "be cautious" and "alert". Could be there are some units that are not performing as they should. Could that be location and temperature? Not sure.

    • When mine goes into "low battery mode" it just descends no matter where it is. It doesn't initiate the return to launch. Is this due to it being under power or another parameter that I need to set that was lost when I updated the firmware?

    • You can configure what action IRIS should take when the battery failsafe is initiated. See here for the choices:

      Your choices are:

      - Do nothing

      - Return to Launch (aka fly home)

      - Land

      Keep in mind, that both RTL and Land can be overriden by you manually. Thus, if Land is triggered while you are in the middle of a lake, you can switch into Stabilize or Loiter and fly to the edge of the lake and land there. Whether you have enough battery to do so is another question. 

      These parameters should not get lost when you upgrade firmware. 

      Personally I would stay far away from flying IRIS with Gimbal and tall legs on 3S Lipos. That experience is just horrible. Going to 4S won't cost you and arm and a leg and give you the experience that you are actually expecting.

    • What's your hover throttle at the beginning and end of a flight with Gimbal and long legs?

      Check here on how to determine that: 

  • Not sure if this will help, but have you tried re-calibrating everything? Things may have been bumped out of whack on heavy landings/crashes.

    • Good idea - I'm going to try that when I adjust the Pixhawk with their "improvement" kit. I'll report back with my findings. I think I'm also going to send an Email to 3DR.

This reply was deleted.