After months of testing AC3.1 is finally available in the Mission Planner and GitHub.

Warning #1: If the vehicle is left landed (but armed) while in AltHold or Loiter mode for more than a few seconds, the vehicle may suddenly jump into the air the moment the pilot raises the throttle above zero.  The reason is the baro altitude may fall while the vehicle is sitting on the ground.  In AC3.2 this bug is fixed because we reset the target before take-off.

Warning #2: Motors will spin (slowly) by default as soon as the copter is armed!  You can switch this feature off by setting the MOT_SPIN_ARMED parameter to zero.

Warning #3: if you see "Bad Gyro" on the HUD then you may have a blown 3.3V regulator.  See this thread for details.

Warning #4: if you use a sonar set the SONAR_GAIN parameter to 0.8 or lower

Warning #5: Trad Heli users should now connect their main rotor ESC to APM's RC8 output

Warning #6: Trad Heli BUG causes loss of collective control in ACRO mode if swash type set to flybarred (i.e. not flybarless).  Will be fixed in AC3.2.


The major improvements over AC3.0.1 are (full list here):

1. Pixhawk support (Tridge & PX4 development team)

2. Autotune of Roll and Pitch gains (Leonard/Randy)

3. Drift mode (Jason)

4. Improved Acro (Rob/Leonard) and new Sport mode (Leonard)

5. Arming, Take-off, Land in Loiter or AltHold

6. TradHeli improvements (Rob) including:

a) support for direct drive tail rotors

b) smoother ramp-up of main rotor

c) reduced collective for better control in stabilize mode (STAB_COL_MIN, STAB_COL_MAX params)

7. Support for SingleCopter (Bill King)

8. Performance improvements resolve AltHold troubles for Hexa & Octacopters

9. Safety Improvements:

a) GPS Glitch detection (Randy)

b) Motors spin when armed (Jonathan Challinger)

c) crash detector shuts off motors if copter flipped for 2secs

d) batt failsafe option to RTL instead of LAND, gps failsafe option to trigger AltHold instead of Land

e) more pre-arm checks of inertial nav speed,

10. Bug fixes:

a) optical flow working again (although performance is still not great because not integrated with inertial navigation)

b) ROI working (use DO_SET_ROI command)


How to upgrade:
Click on the MissionPlanner's Initial Setup >> Install Firmware screen.  The version numbers should appear as "ArduCopter-3.1", then click the appropriate frame icon and it should upgrade as per usual.

Special thanks to Marco and the many beta testers on the AC3.0.1 thread who put their copters at risk during the testing of this new version and uncovered many problems so that you don't have to!  Here are some of their videos: loiter in wind, patio sonar, autotune, autotune2, roi, beach, acro, vrbrain, tricopter, train spotting, radio failsafe, the tree, double loiter


If you haven't seen it recently, please check out the ArduCopter wiki.


Feel free to post comments below and we're going to use the new APM Forum for support issues so please post your support requests there.

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Ok, here is the log of the 3.0.1 perfect for me, the point of view power and autonomy. I was stabilized and in alt-hold. The very beginning of the log may be distorted because of a loose propeller. 

I hope that this will help you find the problem

Many thanks for your time to resolv my worry

with log :)



      I have upload 3.1.1 to my Pixhawk. It have problem. When i will throttle up. I saw HUD on MP is Right Rotate with itself and my Quad have Left Rotate to Crash detection. I check my logs and I don't know is bug or not?


Hi Randy,

you write: "m) Futaba SBUS receiver support"

what does it mean? Will it solve the problem which people experience with Futaba r7008sb receivers?


SBUS, not SBUS-2 at the moment.

Hi Randy, Marco and the DEV Team,

I have just loaded 3.1.1 and the Hex is still flying like a dream, the stability is amazing and it gives me an enormous amount of confidence to just want to go out and fly, fly, and fly some more.

Thanks a heap for all your dedication and hard work, like was you to Michael with MP.

Great work



      Could you try removing the card, plugging it into your PC and formatting the card?  That will erase all log files but it normally fixes the issue.  It may return however.


     I'm not sure if it's related but something has gone wrong with Compassmot.  Could you set these parameters to zero?





That's exactly what I do everytime I get this error. And I noticed that everytime the SD card error pops up, the Card itself is quite warm to the touch. Is this normal?
I have 3 Pixhawks , I replaced the memory card on all 3 with my own . I have never had a problem
And my first Pixhawk is a very early one. Not saying this is what people should do, but I have never had a problem. Was the issue with the card or firmware?


     I'm afraid that in this log too the copter is very underpowered.  By the end of the flight you have to give it 100% throttle just to keep it in the air.

There some wiki information on choosing a battery here.  I think switching to a 4S battery and increasing the KV of the motors would be a good start.

This is *not* a software problem.

Best of luck.


     There were certainly some SD card issues in the NuttX layer of the software.  It also seems though that the firmware is different between SD cards even when ordered from the same manufacturer.  So I hear that the early SD cards that were in the PX4 and the first few hundred Pixhawk were a-ok despite some bad behaviour of NuttX but then next batch was very unhappy.

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