Copter-3.3 released!

After months of testing by the beta-testing team and no significant issue during the soft release, Copter-3.3 has been released.  You can load this version onto your vehicle using the Mission Planner or APPlanner2's Install Firmware screen.

As mentioned previously, this version and all future versions of Copter only work with fast CPU boards like the 3DR Pixhawk (and compatible) boards, VRBrain, NAVIO+, etc. Slower CPU boards (i.e APM2.x) can continue to load Copter-3.2.1 from the MP/AP2.

Support issues should be reported in the APM Forum.  Enhancement requests and confirmed bugs should go into the GitHub issues listThe wiki has been mostly updated but if you spot missing items please report them to the wiki issues list.

The full set of changes can be seen in the Release Notes but the highlights are below.

Known Issues/Warnings:

  • users will need to re-calibrate their accelerometers because of 5c (accelerometer range increase).
  • FrSky telemetry users must set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions
  • this version corrects a long standing issue in the HDOP reporting so values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
  • TradHeli is still in beta testing so it remains on AC3.2.1 for now.

Changes vs Copter-3.2.1
1) EKF replaces DCM/InertialNav for attitude and position estimation which provides more feedback and robustness in case of sensors failures
2) Control improvements:
   a) battery voltage compensation should maintain control as voltage drops
   b) current limiting can be used to reduce the maximum current requested to reduce strain on battery and ESCs
   c) air pressure compensation should reduce need for re-tuning when flying at different altitudes
   d) improved throttle curve should reduce wobbles during descents
3) AutoTune for yaw
4) Cameras & Gimbal improvements:
   a) SToRM32 gimbal support
   b) do-mount-control mission command allows controlling absolute camera mount angle during missions
5) Vibration resistance:
   a) real-time reporting of vibration levels by clicking on Vibe field on HUD (also recorded to logs)
   b) noise weighted average of accelerometers used to weight IMU towards the one exposed to less vibration
   c) accelerometer range increased from 8G to 16G to allow use in higher vibration environments (i.e. reduced "clipping")
6) Other:
   a) improved landing on slopes
   b) retractable landing gear support
   c) channels 9 ~ 12 can be used as auxiliary switches (like ch7, 8)
   d) PX4flow (optical flow) support in Loiter
   e) Brake flight mode (stops vehicle quickly but requires GPS)
   f) allow GPS, Telemetry, SToRM32 gimbal to be connected to any telemetry/serial port
   g) Lidar-Lite V2 support
   h) bug fix to RCMAP - remapped channel's MIN, MAX were taken from incorrect parameters meaning all channel ranges had to be the same
7) Tricopter tail servo parameters (MOT_YAW_SV_MIN, MAX, TRIM, REV)
8) Safety items:
   a) crash check triggers with 30deg lean angle error (for 2 sec) even if pilot's throttle is non-zero
   b) modified pre-arm checks to ensure good quality GPS and compas data
   c) lost copter alarm (hold both sticks down and right)
   d) motor interlock & emergency motor stop features on auxiliary switches (ch7 ~ ch12)
   e) RTL_CLIMB_MIN parameter allows forcing vehicle to always climb a few meters at beginning of RTL
   f) LED flashes green quickly if disarmed with 3D lock and SBAS

Thanks to Marco and all the beta testers who risked their vehicles so we could iron out issues and ensure a more reliable firmware for the wider community. Here are some of their videos:

ChrisN #1, #2, Paul Atkin #1, #2, #3, Gervais #1, #2, #3, Gleb Falaleev #1, #2, Pomaroli, Michael, Robert Baumgartner, De Le, Robert Baumgartner, Robert Navoni, Maciej Karpinski

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  • Moderator

    Wouldn't it be better to not allow arming at all until GPS quality is acceptable, irrespective of mode unless specifically allowed by a non default parameter?

  • ok sir, thanks you Randy . i will learn from experience. Just angry abit, broken two props, cracked arms gimbal adapter.

  • Developer


    6 satellites is really low.  I'd never fly with less than 9.

    I'm a little surprised that it showed an HDOP of 1.33 at arming despite the very low number of satellites.  We probably shouldn't have let the vehicle arm and takeoff in Loiter with such a poor GPS quality..

    During the flight the HDOP jumped up and down between 1.33 and 1.88.

    It looks like the vehicle didn't get very high before you brought it down again.

    I think the lesson here is just to wait until it's got at least 9 satellites before taking off.

  • hi Randy

    just crash few min ago. don't know what happend.. sats till 6, but iris+ is moving around and lose control.


  • hi Randy

    here is my testing follow me frimware 3.3 . something wrong with it, please have a look, i'm using mode ( lead and leash )
    it's look shock and shaking  when my iris+ is moving follow me.

    follow me mode active at ( 1:12 to 3:35 )

    here is video

  • Hi, has anyone been able to make the SBUS output work? Thanks

  • Developer

    There has been one sudden crash while using Follow-Me with Copter-3.3 and Tower-3.2's.

    The cause is not clear but our best guess is an impossible altitude request is being received from Tower.

    We recommend not using Follow-Me for the next few days while we investigate further.

  • Moderator

    Had an odd thing recently, my 'copter would not enter Poshold or Loiter but the were no error messages and I can't see the reason in the logs. My post is here:

  • @Chris&Randy, thanks. It was this simple issue. Droidplanner has served great with APM and very limited use (altitude meter) with Pixhawk. Now it is changed to Tower.

    With this new copter capable of 20 - 30 min flights I can use all mission types needed and parachute function is in use permanently.

  • Developer

    @Justin, yes, THR_MAX disappeared in Copter-3.3 but the MOT_THST_MAX can be used as an alternative.  So by default it is 0.95 which means 95% of the ESCs range is used but you could reduce that to say 0.80 to stop the top 20% of the ESCs range from being used.

This reply was deleted.