ArduCopter 3.0 is ready for widespread use.  To make the transition easier, this time we are asking people to voluntarily upgrade from 2.9.1b for the next month or so before we make 3.0 the default firmware downloaded by the mission planner.  The new version can be found in the Mission Planner's Beta firmware's link,, GitHub and the new Downloads Area.

Warning #1: A bug was found in the FENCE in which if you lost GPS it could lean at extreme angles as it tried to maintain an invalid position.  This is fixed in AC3.0.1-rc1.

Warning #2: This release has not been fully tested on Traditional Helicopters

Warning #3: GPS glitches can cause sudden and aggressive position changes while in loiter mode.  You may wish to reduce the WPNAV_ACCEL to 100 and Loiter PID to 0.2 (from 1.0) to reduce aggressiveness.

Improvements over 2.9.1b include:

  • Inertial Navigation for Loiter and Auto meaning much more accurate control (Randy,Leonard,JonathanC)
  • 3D navigation controller follows straight lines in all dimensions between waypoints (Leonard,Randy)

         WPNAV_SPEED, WPNAV_SPEED_UP, WPNAV_SPEED_DN, WPNAV_ACCEL allows configuring speeds and acceleration during missions

  • "compassmot" to compensate for interference on compass from the pdb, motors, ESCs and battery.  (Randy,JonathanC) (Set-up video here)
  • Safety improvements:
    • simple Tin Can shaped Geo Fence
    • pre-arm checks to ensure all calibration has been performed before arming (can be disabled by setting ARMING_CHECK to zero).  (video description here)
    • GPS failsafe - switches to LAND if GPS is lost for 5 seconds
    • stability patch improvements to stop rapid climbs in very overpowered or overtuned copters
  • Circle mode improvements including "panorama" when CIRCLE_RADIUS set to zero (Randy,Leonard)
  • SONAR_GAIN parameter added to allow better tuning of sonar surface tracking
  • CH8 auxiliary switch (same features as CH7)
  • works on PX4 (some minor features still not available) (Tridge,PatH)

How to upgrade:

1. Make sure you are using Mission Planner 1.2.59 or newer.

2. Click on the MissionPlanner's Firmware screen and click the "Beta Firmwares" link on the bottom right.  The version numbers should update to "ArduCopter-3.0.1rc2", then click the appropriate frame icon and it should upgrade as per usual.

3. Reduce the Loiter and Alt Hold PIDs if you have modified them from the defaults.  The modified PID values for the 3dr frame can be seen in the image below.

Note: Nav parameters have been combined with Loiter so do not be concerned if you can't find them.

4. If you purchased an APM prior to March of 2013, update your PPM encoder to the latest firmware.

5. Try out the new version in stabilize mode first, then alt-hold, then loiter and finally RTL and Auto.

Special Thanks to MarcoDaveC and the rest of the beta testers for putting their copters at risk during the extended testing period.  Some of their videos can be found hereherehereherehere and here.  Thanks also to MichaelO for the MP changes required for this release.

All feedback welcome.  Please put your questions, comments (good and bad!) below.  

Added by Craig:

Please watch Randy's videos on setting up and flying APM-Copter 3.0 before you go flying.  They are excellent!

3DR Quad Set-Up Suggestions
AC 3.0 "Live" Compass Calibration
AC 3.0 CompassMot Setup      
AC 3.0 Pre-Arm Checks            
AC 3.0 Fence                               
AC 3.0 Maiden Flight Checks   

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The only problem seems to be that people have been used to MP automatically sending the re-boot command to the APM when you go to the Terminal screen.  We have changed this functionality to prevent an accidental inflight reboot if you accidentally select Terminal.  It is now a 2 step process where you have to select Reboot after entering the Terminal window.

Craig, what do you think about adding a warning window before to send the reboot command ?

"APM board will be rebooted before to enter CLI mode - Never do this during flight. Are you sure ?"


Hi Craig, FWIW, the note below the button is not very obvious and easily missed (I'm guilty too of missing it). The added safety of this change is very good though.

Michael and I have spoken about how to change the instructions to make it clearer. I like your wording.  I will recommend we add that warning as well.


Hi guys,

I had a bad crash today running AC 3.0.1rc1 on APM2.5 : everything was fine, playing around with Stab/Alt Hold/Loiter flight modes, and all of sudden, copter crash without any kind of warnings...

Here is the log, can you understand what happens ? I don't !





I have my failsafe set trough my Tx. If a signal loss occurs, Rx will go into failsafe mode and activate RTL on APM.

I did NOT use APM failsafe function. Is there any disadvantage not using the APM failsafe?

No disadvantages AFAIK. The APM failsafes have an advatage of being more complex in decision making. Ie. it won't fail if you loose radio contact and you are flying a mission.

TX failsafe is a common way people enable RTL or LAN, depending on your preference

Sounds like what mine did.  I lost signal and failsafe kicked in.  Went into RTL. It Came back and i thought it was going to land.  Then it went nuts and flew off and ended up flying into the woods totaling it.  Dont have a clue what went wrong.  Not sure what to look for in the logs.  I attached it.  Here is a vid as well


Hi; i'm Pablo from Argentina...I just made my first flight with my quad shaped TBS (clone) and version 3.0.1, and I encounter the following problem. When I leave in a fixed position, a few moments are rotated 45 degrees to the right and then keep turning but very slowly, so flight to orient to another position and the same thing happens again rotated 45 degrees to the right...

I performed the calibration of the compass 2 times as indicated by the video, I put the magnetic declination manually or automatically and continues all the same.

I tried disabling the compass and the problem disappears; remains perfectly pointing to the position I instructed.

What is happening to me?

What should I check?

Thank you!

Pablo: that sounds like magnetic interference. Try mounting your APM higher (at least a few inches above your PDB). The further you can get it from power electronics, the better it will perform.

There is a disadvantage of not using the APM failsafe.  If you checkout this wiki page you'll see an image about 1/3 of the way down.  What that's showing is that there are actually 3 levels to the throttle failsafe:

      1. loss of tx/rx connection

      2. loss of power to the rx

      3. failure of ppm encoder on APM board

So if you only set-up the receiver to move channel 5 to RTL then you're giving up on #2 and #3.

You don't necessarily need to set-up a flight mode to RTL in the APM for failsafe to work.  You only need to do that if your tx/rx forces all channels to change position when a failsafe far as I know this is only the case for some FrSky tx/rx.  Futaba for example allows you to set it up so that only channel 3 is pulled low when the tx/rx lose contact.

All presume a fully functional APM and failsafe.

It seems to me that the advice in scenarios when things go badly is "switch to Stabilize mode, recover, land and investigate".  Adding extra layers of complexity also invite additional methods of error.  The switch to stabilize is sound advice.

It seems to me that the fly away and crashes are often attributed to fail safe events that don't behave well or are setup incorrectly.

I suppose a perfectly operational copter would minimize the risk of advanced failsafe modes (modes at higher than stabilize in complexity).  With the GPS instability and "magnetic declination anomalies" that have been thrown about recently, a radio failsafe that cuts the throttle and allows the copter to fall to the ground or a APM failsafe that switches to stabilize would seem to be better options.

Nobody wants to crash...but I'm struggling with trusting the auto modes of the APM, incorporating them into a failsafe mode just doesn't make me feel warm and fuzzy inside...

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