APM:Plane 3.3.0 released

[color=#0000FF]APM:Plane 3.3.0 released[/color]

The ardupilot development team is proud to announce the release of version 3.3.0 of APM:Plane. This is a major release with a lot of changes. Please read the release notes carefully!

The last stable release was 3 months ago, and since that time we have applied over 1200 changes to the code. It has been a period of very rapid development for ArduPilot. Explaining all of the changes that have been made would take far too long, so I’ve chosen some key changes to explain in detail, and listed the most important secondary changes in a short form. Please ask for details if there is a change you see listed that you want some more information on.

[color=#0000FF]Arming Changes[/color]

This is the first release of APM:Plane where ARMING_CHECK and ARMING_REQUIRE both default to enabled. That means when you upgrade if you didn’t previously have arming enabled you will need to learn about arming your plane.

Please see this page for more information on arming:


I know many users will be tempted to disable the arming checks, but please don’t do that without careful thought. The arming checks are an important part of ensuring the aircraft is ready to fly, and a common cause of flight problems is to takeoff before ArduPilot is ready.

[color=#0000FF]Re-do Accelerometer Calibration[/color]

Due to a change in the maximum accelerometer range on the Pixhawk all users must re-do their accelerometer calibration for this release. If you don’t then your plane will fail to arm with a message saying that you have not calibrated the accelerometers.

[color=#0000FF]Only 3D accel calibration[/color]

The old “1D” accelerometer calibration method has now been removed, so you must use the 3D accelerometer calibration method. The old method was removed because a significant number of users had poor flights due to scaling and offset errors on their accelerometers when they used the 1D method. My apologies for people with very large aircraft who find the 3D method difficult.

Note that you can do the accelerometer calibration with the autopilot outside the aircraft which can make things easier for large aircraft.


After an auto-landing the autopilot will now by default disarm after LAND_DISARMDELAY seconds (with a default of 20 seconds). This feature is to prevent the motor from spinning up unexpectedly on the ground
after a landing.

[color=#0000FF]HIL_MODE parameter[/color]

It is now possible to configure your autopilot for hardware in the loop simulation without loading a special firmware. Just set the parameter HIL_MODE to 1 and this will enable HIL for any autopilot. This is designed to make it easier for users to try HIL without having to find a HIL firmware.

[color=#0000FF]SITL on Windows[/color]

The SITL software in the loop simulation system has been completely rewritten for this release. A major change is to make it possible to run SITL on native windows without needing a Linux virtual machine. There should be a release of MissionPlanner for Windows soon which will make it easy to launch a SITL instance.

The SITL changes also include new backends, including the CRRCSim flight simulator. This gives us a much wider range of aircraft we can use for SITL. See dev.ardupilot.com/wiki/simulation-2/ for more information.

[color=#0000FF]Throttle control on takeoff[/color]

A number of users had problems with pitch control on auto-takeoff, and with the aircraft exceeding its target speed during takeoff. The auto-takeoff code has now been changed to use the normal TECS throttle control which should solve this problem.

[color=#0000FF]Rudder only support[/color]

There is a new RUDDER_ONLY parameter for aircraft without ailerons, where roll is controlled by the rudder. Please see the documentation for more information on flying with a rudder only aircraft:

plane.ardupilot.com/wiki/ardupla … udder_only

[color=#0000FF]APM1/APM2 Support[/color]

We have managed to keep support for the APM1 and APM2 in this release, but in order to fit it in the limited flash space we had to disable some more features when building for those boards. For this release the AP_Mount code for controlling camera mounts is disabled on APM1/APM2.

At some point soon it will become impractical to keep supporting the APM1/APM2 for planes. Please consider moving to a 32 bit autopilot soon if you are still using an APM1 or APM2.

[color=#0000FF]New INS code[/color]

There have been a lot of changes to the gyro and accelerometer handling for this release. The accelerometer range on the Pixhawk has been changed to 16g from 8g to prevent clipping on high vibration aircraft, and the sampling rate on the lsm303d has been increased to 1600Hz.

An important bug has also been fixed which caused aliasing in the sampling process from the accelerometers. That bug could cause attitude errors in high vibration environments.

[color=#0000FF]Numerous Landing Changes[/color]

Once again there have been a lot of improvements to the automatic landing support. Perhaps most important is the introduction of a smooth transition from landing approach to the flare, which reduces the tendency to pitch up too much on flare.

There is also a new parameter TECS_LAND_PMAX which controls the maximum pitch during landing. This defaults to 10 degrees, but for many aircraft a smaller value may be appropriate. Reduce it to 5 degrees if you find you still get too much pitch up during the flare.

[color=#0000FF]Other secondary changes in this release include:[/color]

[li] a new SerialManager library which gives much more flexible management of serial port assignment[/li]
[li] changed the default FS_LONG_TIMEOUT to 5 seconds[/li]
[li] raised default IMAX for roll/pitch to 3000[/li]
[li] lowered default L1 navigation period to 20[/li]
[li] new BRD_SBUS_OUT parameter to enable SBUS output on Pixhawk[/li]
[li] large improvements to the internals of PX4Firmware/PX4NuttX for better performance[/li]
[li] auto-formatting of microSD cards if they can’t be mounted on boot (PX4/Pixhawk only)[/li]
[li] a new PWM based driver for the PulsedLight Lidar to avoid issues with the I2C interface[/li]
[li] fixed throttle forcing to zero when disarmed[/li]
[li] only reset mission on disarm if not in AUTO mode[/li]
[li] much better handling of steep landings[/li]
[li] added smooth transition in landing flare[/li]
[li] added HIL_MODE parameter for HIL without a special firmware[/li]
[li] lowered default FS_LONG_TIMEOUT to 5 seconds[/li]
[li] mark old ELEVON_MIXING mode as deprecated[/li]
[li] fixed 50Hz MAVLink support[/li]
[li] support DO_SET_HOME MAVLink command[/li]
[li] fixed larger values of TKOFF_THR_DELAY[/li]
[li] allow PulsedLight Lidar to be disabled at a given height[/li]
[li] fixed bungee launch (long throttle delay)[/li]
[li] fixed a bug handling entering AUTO mode before we have GPS lock[/li]
[li] added CLI_ENABLED parameter[/li]
[li] removed 1D accel calibration[/li]
[li] added EKF_STATUS_REPORT MAVLink message[/li]
[li] added INITIAL_MODE parameter[/li]
[li] added TRIM_RC_AT_START parameter[/li]
[li] added auto-disarm after landing (LAND_DISARMDELAY)[/li]
[li] added LOCAL_POSITION_NED MAVLink message[/li]
[li] avoid triggering a fence breach in final stage of landing[/li]
[li] rebuild glide slope if we are above it and climbing[/li]
[li] use TECS to control throttle on takeoff[/li]
[li] added RUDDER_ONLY parameter to better support planes with no ailerons[/li]
[li] updated Piksi RTK GPS driver[/li]
[li] improved support for GPS data injection (for Piksi RTK GPS)[/li]
[li] added NAV_LOITER_TO_ALT mission item[/li]
[li] fixed landing approach without an airspeed sensor[/li]
[li] support RTL_AUTOLAND=2 for landing without coming to home first[/li]
[li] disabled camera mount support on APM1/APM2[/li]
[li] added support for SToRM32 and Alexmos camera gimbals[/li]
[li] added support for Jaimes mavlink enabled gimbal[/li]
[li] improved EKF default tuning for planes[/li]
[li] updated support for NavIO and NavIO+ boards[/li]
[li] updated support for VRBrain boards[/li]
[li] fixes for realtime threads on Linux[/li]
[li] added simulated sensor lag for baro and mag in SITL[/li]
[li] made it possible to build SITL for native Windows[/li]
[li] switched to faster accel sampling on Pixhawk[/li]
[li] added coning corrections on Pixhawk[/li]
[li] set ARMING_CHECK to 1 by default[/li]
[li] disable NMEA and SiRF GPS on APM1/APM2[/li]
[li] support MPU9255 IMU on Linux[/li]
[li] updates to BBBMINI port for Linux[/li]
[li] added TECS_LAND_PMAX parameter[/li]
[li] switched to synthetic clock in SITL[/li]
[li] support CRRCSim FDM backend in SITL[/li]
[li] new general purpose replay parsing code[/li]
[li] switched to 16g accel range in Pixhawk[/li]
[li] added FENCE_AUTOENABLE=2 for disabling just fence floor[/li]
[li] added POS dataflash log message[/li]
[li] changed GUIDED behaviour to match copter[/li]
[li] added support for a 4th MAVLink channel[/li]
[li] support setting AHRS_TRIM in preflight calibration[/li]
[li] fixed a PX4 mixer out of range error[/li][/ul]

Best wishes to all APM:Plane users from the dev team, and happy flying!

Thanks to all devs. :smiley:
Looking forward to test this release soon.

Excellent work! Thank you to the dev team and beta testers!

Thank you for the smooth transition from landing approach to the flare and TECS_LAND_PMAX

Does this also afects the transition from last WP flight to Land sequence or just Land to Flare?

@flyboy, just the flare transition. I think we could improve the transition from last WP to landing approach some more as that can be a bit rough, especially if it involves a sharp turn.

Many thanks for the new release

  1. Could you please let us know where to read more about the new Accelerometer Calibration
  2. Since the old “1D” accelerometer calibration method has now been removed how do I set the model level after calibrating the autopilot outside the aircraft ?

Thanks for the new release! Can’t wait to test the improvements on accelerometer handling!

Thanks for all the hard work!

I have a large airplane and it’s also a real pain to take the Pixhawk out. I current have a real good 6-point cal. Will it fly ok if I just turn off the arming check or should I just stay with 3.2.3?

How accurate does the positions have to be? Can I just hold it at what looks like the correct angle?

I probably won’t take it apart and do the accurate accel cal until end of the season (November).


@Mike, unfortunately the change to the accel range means previous accel cal values are no longer valid.
Only the first position needs to be accurate (level). The others can be quite a way off (10 to 15 degrees is fine).
Sorry for the inconvenience!

I was having problems with 3.2.3 on PixHawk after doing one axis leveling. Sometimes horizon wasn’t correct after booting. Was also getting bad gyro health message sometimes. I figured it was something I was doing wrong as I’m new to PixHawk (but not APM). Was happy to see 3.3.0 fixes today, installed it and did 6 position calibration. It seems to have corrected my issues. Will fly it in the morning. Thank you for all the great code!

Hi Tridge
Havent been paying attention lately to updates, but noticed after ‘fiddling’ awhile with a plane and
firmwares that NMEA gps was removed. Thought something was wrong here:)
Was if to release codespace? This gps is only nmea :frowning:


Plane 3.3.0

I am only able to arm via MP. Calibration for ch 4 is not registering stick movement correctly…ch 1,2,3 are calibration fine

Hey all. What happened to the Single Axis Leveling for PLANE configuration on the new update in mission planner. I only see 3 axis. Not good for a large aircraft. Are you going to put that option back in? Or how do I do the single axis LEVEL in the new update?
Please let me know.

Thanks guys;)

[quote=“Dartt-V Systems LLC”]Hey all. What happened to the Single Axis Leveling for PLANE configuration on the new update in mission planner. I only see 3 axis. Not good for a large aircraft. Are you going to put that option back in? Or how do I do the single axis LEVEL in the new update?
Please let me know.

Thanks guys;)[/quote]

Have a look at the very first post in this thread, about the 4th item down :wink:

OK developers… I have been using Mission Planner for years now. I disagree with removing “1D accel” calibration method!!!
I have over 2000 flights under my belt with no issues with 1D calibration on Pixhawks and APM controllers. The individuals having issues just don’t know how to use it! I have larger airplanes I use the calibration on and it is nothing but a big bunch of crap to use 3D accel on fixed wing.
So what do I need to do to get it back on Mission Planner?? Put it under advanced category or something so users with “issues” don’t have to use it.
Please HELP and Vote to Reinstate 1D accel calibration… I will pay to have it done.
Thank you all;)

The developers have too much integrity to reimplement less reliable 1D calibration.
But you will find lots of freelancers that can make you an custom version with that.

Or, you can just install your AP in a box, on another plate in your plane, and just rotate that box on the flat area, when needing a calibration.