Copter-3.3 beta testing

Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.

Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.

Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).

Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station.  Video description is here.  The bug is fixed in Copter-3.3.1 so we recommend upgrading.

Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting.  HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features

Copter-3.3.1 is available through the mission planner.  The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.

Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.

Changes from 3.3:

1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff

2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)

Changes from 3.3-rc11:

1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent

Changes from 3.3-rc10:

1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF

Changes from 3.3-rc9
1) EKF improvements:
    a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
    a) fix INS3_USE parameter eeprom location
    b) fix SToRM32 serial protocol driver to work with recent versions
    c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
    d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
    a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
    b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
    c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
    d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
    e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)

Thanks for your testing!

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  • I had my first EKF inconsistency error today. I've been flying 3.3 rc5 for many flights over the past weeks with no errors but this occurred at take off and my quad flew fine in Stab mode but anything using GPS was locked out. I landed and reinitialized and all was well. Let me know if the logs would be of use I'll try and find the flight. I've been fine tuning an upgrade to Alexmos 32 bit on my gimbal so the quad has been on and off several times.

    It's interesting that most of the Dev's have been AWOL for the past few days. I assume they are knee deep in sorting out the Solo issues and the EKF errors. I suspect the code is getting petty complex so it will be harder and harder to add new functions and debug. I wonder if QNX which offers a very partitioned operating environment for critical applications would be worth a look or if it can run on the Pix processors.


  • Hi Randy,
    I don't know the proper way to request an enhancement, but I would like to see the default for WP_YAW_BEHAVIOR = 3, which is yaw follows path. This makes for much smoother automated flights, and I think it is the behavior that people would intuitively think it would do. It took me a long time to figure out this was what I needed to set so that it doesn't jerk to point to the next waypoint.



    • Another addition might be to add Rate Yaw kI to Ch6 Opt. Is that an oversight, or maybe there is a reason that it is not done? It would be helpful to me, though.



    • @Rick Huebner: 

      What you're describing is fine in some instances, with a three axes gimbal possibly not.

      The gimbal yaw axis smooth out when a new waypoint  is reached.

      In  Mission planner a waypoint with 1 second of wait insure more precision and smooth things out as well. All depends what is the use of the waypoint.

      Spline waypoints do magic in video take. :-) 


  • I feel fortunate; no errors reported for anything on 3.3 rc5 on two copters, although today I did one 'Bad Gyro Health' warning on first startup on the one with AUAV-X2 FC.

    My biggest nemesis is getting the tuning right. It seems that I get much better results when using rigid props (wood/CF) vs say APC SF.  The APC MR appear to do do better than the SF. I'm applying this observation to heavier copters (> 2000g). I believe the SF props flex too much and cause instability. This may be an issue with Auto Tune, but so far the quad will not hover stable, particularly in even slight wind gusts. 

    After putting T-Motor 15" CF props on the Spy 750 Y6, it made a world of difference. The cheaper Tarot CF props were too bendy. Xoars worked well too. 

    I'm looking forward to hopefully Auto Tune getting better with each release.  

  • Guys. I really need help...

    I'm really struggling to understand a recent problem my hexa developed. It has been flying with no problems until yesterday.

    It developed a sudden lean to front/right and I cannot understand what the problem is. You can see the problem around the 3 min mark on the log. Plotting channel 5 vs channel 6 shows you the problem. 

    It was running 3.2.1 beautifully and in last resort I installed 3.3 rc5, made a full default restore and started fresh. Unfortunately it did not solve it..

    I need some guidance please.

    Thank you


    • Hopefully this isn't too obvious, but I assume you tried an accel calibration. Not sure why, but mine seem to drift out once in a while. My Solo was new as of Saturday, and by Tuesday, it had developed a tendency to drift pretty hard to the left. Hooked it to APM Planner, and sure enough the accel calibration was out. Calibrating on a level surface fixed it.

      Beyond that, I guess I would check to make sure your FC is sitting at the same orientation as your frame. Once I put the top shell on my Iris, and a cable got pushed under the Pixhawk. It was enough to tilt it a few degrees, which led to some drift.

      • Developer


        I'm probably off topic mentioning this but one possible explanation for the lean you saw develop after a couple of days on the Solo was that the Pixhawk2 (aka PH2) has built-in vibration isolating foam and it's possible the IMU could shift around a bit within the case especially after a long boxed up trip from China.  I'm totally guessing, no basis in actual experience or knowledge - I just want to point out this possibility.

        FYI - there's actually 3 IMUs in the PH2 - two are vibration isolated and one is hard-mounted, the pre-arm checks compare them all so they can't be very far off from each other before the pre-arm checks will catch it and stop you from arming.

      • Yes. When I updated to 3.3 rc5 I did all calibrations and settings from zero.
        I don't know if it is an mechanical, electronic or something else fault. Mine does not drift at all and suddenly has that front / right lean. On the bench I cannot provoke any motors out of sync problem. Never had out of sync problem before.
        • Personally, I'd be inclined to try the calibration again. I've performed one, then checked it an hour later to find it was out slightly (Or maybe it's because lush grass doesn't work well as a "level surface", ha ha). And it doesn't take much to affect it. I would also check my TX and make sure one of the trims hasn't been bumped out of adjustment. I've bumped one of my trims before, which caused drift even though the calibration was spot-on. Sounds like you know to check these things already, so hope these don't sound like lame suggestions.

This reply was deleted.


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