APM:Plane 3.3.0 released

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.

Arming Changes

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.

Re-do Accelerometer Calibration

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.

Only 3D accel calibration

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.

HIL_MODE parameter

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.

SITL on Windows

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 http://dev.ardupilot.com/wiki/simulation-2/ for more information.

Throttle control on takeoff

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.

Rudder only support

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:

http://plane.ardupilot.com/wiki/ardupla ... udder_only

APM1/APM2 Support

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.

New INS code

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.

Numerous Landing Changes

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.

Other secondary changes in this release include:

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

Many thanks to everyone who contributed to this release. We have a lot of new developers contributing which is really great to see! Also, apologies for those who have contributed a pull request but not yet had it incorporated (or had feedback on the change). We will be trying to get to as many PRs as we can soon.

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

Views: 15544

Comment by Andrew Tridgell on May 25, 2015 at 6:49pm

@Adam, the APMPlanner2 bug has been fixed, and Bill plans to do a new release later today. I haven't tested the fix yet

Comment by Adam Alexander on May 25, 2015 at 6:58pm

Thank you!
Comment by Greg O on May 25, 2015 at 7:33pm

@Tridge, @Keith G, Removed my rfd900 from the plane and the jitter still exists... Wire path between the futaba VS pixhawk is identical, so ill see if I can get some scope captures from the pixhawk and compare to futaba and frsky outputs..

Ill try some chokes on the telemetry modem line as well.. 

Comment by Grant Morphett on May 25, 2015 at 8:10pm

Hi everyone.  If your having issues with MissionPlanner connecting to your Pixhawk its because the USB drivers may need an update.  There is a couple of things you can do.

Firstly try a different USB port.  For me it was the 3rd USB port I tried that worked.  No doubt this is due to the subtle differences in the hardware between USB ports and the associated software driver.

The second thing you can do is uninstall MissionPlanner and then install the latest version again.  By installing from the .msi the USB drivers are updated.  Some of you will of noticed if you downgraded to 1.3.26 it started working however this is only because the latest USB drivers were installed when you installed 1.3.26.  If you install 1.3.27 that should also resolve the issue.

Thanks, Grant.

Comment by Greg O on May 25, 2015 at 8:34pm

@Grant I also had issues with drivers on the Windows 8.1 platform, where it kept loading from WindowsUpdate.. Finally I manually uninstalled the drivers (Insert device, detect, uninstall, repeat) and installed Mission Planner. 

Comment by Andrew Tridgell on May 25, 2015 at 8:44pm

@KeithG, that sort of symptom is usually caused by a RC framing issue. I don't think you've actually said what sort of receiver you have, but I think it is likely that it has framing errors.

To explain what I mean by framing error lets take the example of PPM-SUM. A PPM-SUM signal has a sequence of pulses, one for each channel. It then has a long pulse indicating that it is about to start over with the first channel again. Many receivers use a constant frame width, which means as the pulses for each channel get wider the amount of room for the "end of channels" marker gets less. If it gets small enough then the Pixhawk cannot distinguish the end of the channels, and starts mixing up channels.

Try configuring your transmitter to use less channels. For example, if its a 9 channel transmitter then get it to only send 7 channels. Also make sure any unused channels have minimum value.

To really delve into this deeply you need a logic analyser, but just lowering the number of channels is likely to help.

Cheers, Tridge

Comment by Keith G on May 25, 2015 at 9:27pm

I am using a futaba 7c, like randy uses. And the receiver is a r617f. I could reduce it to 5 for plane to see if it will help but I seem to have the same issues with copter. These issues are debilitating and I don't trust flying right now. I'm using the encoder from 3dr and plugged into the rc port on the Pixhawk and 1 2 with a jumper on the apm. I would really appreciate some guidance.
Comment by Gytis Grigaravicius on May 26, 2015 at 2:27am

Here's my first successful auto-launch test with APM:Plane 3.3. First few tries with 200ms throttle delay ended up in crashes, so for this one I lowered delay to 100ms and increased max pitch angle to 25deg. Still have to investigate why throttle was only pushing up to 85%. Had no time to check parameters, but I suspect that TKOFF_THR_MAX is set to 0, while I have THR_MAX for auto modes set to 85%. I'm not reading comments here too often, so if you want more details about my configuration please leave a comment in youtube.

Comment by Andrew Tridgell on May 26, 2015 at 2:37am

@Gyris, I'm glad it worked for you. If you want to find out why the throttle delays on launch then I'd need to see a DF log.

Cheers, Tridge

Comment by Andrew Tridgell on May 26, 2015 at 2:40am

@Keith, I checked with Randy, and while he does use that transmitter, he doesn't use the r617f receiver as it doesn't have PPM-SUM. He uses a FrSky TFR4B, which gives direct PPM-SUM.

I strongly suspect you have a hw problem with the receiver, or with the ppm-sum encoder. Maybe try getting the FrSky receiver?


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