Auto Mode Without Airspeed ??

hello all

I Hop to find real useful information and solutions .



 - APM 2.6 ( also test with Pixhack )

 - GPS ublox

 - MiniOSD



 - Mission planner 1.3.32

 - Arduplane Firmware 3.4

I test the Auto mode in the flight but when I change Flight mode to Auto the throttle stop immediately , 

some advice in other discussion ( )

says the problem with airspeed.

I did Ground test with Distance and Altitude ,

I disable the air speed and set the cruise throttle to 60% .

and test the auto mode in ground and it's not working . after that I set 4 waypoints  .

then I moved with car to small  hill around the waypoints and change the flight mode to Auto and the throttle works fine , While i am driving the motor slow and increase and some time stops and start automatically

note : the air speed is disconnected and disable from the parameters .

any information describe this behaviors ? 

Dose it mean that the Auto mode will work fine in the Air ?

What other parameter will effect the flight with disabling the Airspeed (ex. Stall prevention , Angles limit , TECS , and Other parameters) ?

Until now I didn't get the perfect information and advice , Hope I can find it here .

I don't want to loss my plane again :)


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  • What skywalker and motor you have? I hope you need more config, as others recommend, first try to fly in loiter or cruise, if this modes don't work, don't try to fly in auto (crash warantee). At the begining  of my skywalker life, when I tried to fly auto modes, the plane loose altitude very fast and cost me two crashes and lot of time and some help to discover that bad config was the problem; perhaps others can help you if you share a log.

  • @James Downing ,

    nice information ,

    do you mean that the Flight controller lock the throttle in the ground based on the Altitude ?

    I Test it again and as usual when change Auto mode Plane start decent and loss altitude .

    I need to know what is the relation between the Auto mode and Altitude ..

    waiting for any information ..
    • I think the throttle lock is likely based on multiple sensors, probably altitude and velocity.

      In auto mode, it begins the waypoint schedule that you have applied via the ground station.  If you have a waypoint applied, it will attempt to fly to that point, and then fly on to the next, until it has no more waypoints, at which point it will either land or circle (loiter).  Check your waypoint altitude.  It may be that your waypoint as an altitude applied at ground level, in which the plane will drop altitude in order to hit it.  Also check that your altitude is entered in AGL (above ground level), and not ASL (above sea level).

      Hope that helps you find your issue.

    • thank you so much @James Downing for your useful information .

      the altitude in the mission planner in the planning tab upper right , under the coord is using ASL

      when I set the waypoint to ( 150 m ) using (terrain map or relative ) and select the (Verify Height) check box  

      - the altitude is determine using ASL  ex (my alt 800m ASL) WP alt ( 950 m)

      when I set the waypoint using (  Absolute )

      - - the altitude is determine using AGL ex (my alt 800m ASL) WP alt ( 150m)

      what should I use to avoid the plane decent ..?

    • If you figure out the altitude question please post it. I've had the issue where the altitude was correct until it got a GPS lock then it jumped to what it is above sea level which I could care less about and don't want. I wanted zero from where it booted from. Thanks.

    • I'd try a mode like Cruise to see if that works for you before going further with Auto.  Auto is a fairly advanced mode, and you need to be sure the rest of the system is operating properly first.  Cruise mode or loiter mode should operate using the full sensor array.  If those two modes are working well, then that may help narrow down your issues to something relating to the waypoints.  If those two modes also dive, then that should mean that a sensor may not be calibrated properly.  You say you've only used manual and stabilize, those modes use very abbreviated sensor input so you're not using the whole system that Auto uses.

  • As someone else said, switching to auto mode on the ground will not allow the throttle to turn on as a safety measure.

    Test it in the air again, worst case, just switch the mode out of Auto if the motor doesn't turn on again.

    The throttle turning on and off in the car kinda makes sense since the autopilot doesn't know what the heck is going on.

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