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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When I flash it back to 3.2.1, the GPS works. MP shows "3D Fix" again.

No one an advise ? Or because it´s weekend?

If it's an Alien 680 frame, I have one too and am having problems getting it tuned. From what I've heard many do.  Everything is tight and COG good. AT was done with AGGR at .07.  The copter is not stable after 2 AT's.

My PID's are quite different than yours. I'm starting to think I need to put some good CF props on this bird. With the cheap Gemfan CF VIBE's were lower, but over 500g thrust I don't use them. Currently it has APC MR 13x5.5 and it just doesn't seem to be as responsive plus does wobble.

I've never had a quad with these goofy PID's.

Hulk: Try to repeat pitch autotune or try to reduce it manually, thats in part your wobbles ccd and other problem is that if your camera wobbles probably isn't ccd, it's cmos, are you shure?

Yes, a wonderfull weekend here ;) .....but I'm not have with me my copter :(

The cam is a sony 600tvl.it should be ccd. It's no rolling shutter...more big waves.
I think arducopter has still mega problems with alien type frames. I make a new pitch tune and test or i will reduce p. I don't understand the peaks. Normall it should so clean like yaw.perhaps randy or leonhard thall has an idea. And stab p should be higher.

This is also a Alien 680 tuned at an aggr of .05.  The tune is is rock solid.  This is an X8 though with Sunny Sky 4108s 14 480kv motors and 15" propellers running 10ah4s packs.

was it your 1st autotune try? did you change anything else?

do you have a short log with stabilize and a poshold?

i don´t see my problem optical....only in log and fpv cam


I may be in a wrong thread, but since I am using Pixhawk with 3.3.1 firmware I think my question is relevant.

My setup is shown in attached pic. It is modified Flamewheel clone with RCTimer 2610-920 kv motors, Platinum 30A ESC's. I made it for night flight photos (and possible FPV, so there are 3D field separated camera (Blackbird-1) with 2W 930MHz video transmitter). For regular flight there are two 10W  60 deg. LED and for light effects 100W focused LED on 1 axis gimbal. All peripheral equipment powered from separate battery. Lights controlled via RC ch 9 and 10 through Turnigy solid state relays. The whole thing weight is 2045 g with both batterys, it hover at 45 - 50% throttle.

It flys perfect in Stabilize mode. I tested vibrations, it is below +/- 0.1 g on all axis. When I switch to AltHold mode it almost hold but slowly loosing altitude, it is erratic in Loiter. In log it shows EKF_CHECK-2 error. I read through many discussions on several forums. In most cases it is either vibration or Yaw-error (mine is below 0.2). 

I just did complete calibration of both magnetometers with all peripherial ON (errors were balow 0.2) and flew it for 3 min on my backyard - same effect - got EKF error right after switching from Stab to AltHold (did not even use Loiter). Log.bin file from latest flight attached.

Any ideas? I am kindly asking for Randy's comments (it seems that he is the most active in the discussion of this issues in many forums).

Could it be PID tuning, I am still on default values (at first test flight it seems stable enough and pretty responsive, so I decided not to tweak it.) Tuning snapshot below.


It does not seem to paste jpg file in edit mode. will post it in next post.


This is on an Alien 680 also. Flys great.

HI. Just next post to add PID tune page 


Autotune woes!

Still having no success getting a decent tune on my QAV250 after upgrading to BLHeli 14. I upgraded again to 14.2 and discovered that one of the ESC's hadn't calibrated properly, so I fixed that and had another go. Basically the copter tolls back and forth like its on a soggy elastic band and its pretty easy to flip over.

I'm just trying to tune roll at this point. The first tune resulted in it still rolling back and forth with lots of overshoot like it was on a soggy elastic band. The tune didn't complete because of battery failsafe. Log attached.

I then lowered the PIDs and Stab P to try and get better initial stability which resulted in an even more unflyable copter - it flew sideways and I could recover it at which point it flipped and crashed. Not much of a log but its attached. I'm guessing that one of the values is the wrong thing to do, but if Leonard is able to give me some hits I would be really grateful!


Well Hello everyone, nice to be back in this old familiar forum! Sorry for the Intrusion, just wanted to say hi to all the people that taught me something about flight controllers and piloting during my APM 2.6 days. After a Tragic and Horrible Decision to try out XAircraft MINIX, i am now back to what works, Pixhawk 2 and Solo. 

Just a Quick question if you guys dont mind (because most people who have a Solo or New pixhawk dont really remember APM 2.6) What happened to the parameter that turned your aircraft Tail IN when Landing from an RTH? i know the WP_YAW_BEHAVIOR for pointing home, but cant find the the Tail in Land parameter. if i am in the wrong place, please be kind to a weary pilot who  hit his own RTH button only to land here, please point me in tot he direction of Tower/Solo questions

nice to be back i have missed you maniacs and brainiacs! 



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