Please help to diagnose; APM2.6 Fly away during RTL

Hi Anyone,

Looking for some advice, What happen during flight?

5 days ago, my Octocopter size 1000 with APM 2.6 FW3.1.5 has Flyaway during RTL by switch activated (This is not first time we test RTL by switch activated, the past had fine with no any issue) and can not regain by deactivating RTL switch to loitetr and Althold mode, so it flew away until hit with the tree at approx 8.5m high. The event as below details;

  • We take off in Althold mode.
    -Fly forward to approx. 10 m away from set Home point.
    -We change flight mode to Loiter and wait for some period and it look OK.
    -We activated RTL by switch at approx. 5 m high and 10 m away from Home point.
    -My drone slow shot to 18 m high as i setup in MP and fly backward to home point correctly. when drone reached the home point, it hover over the home point for a few seconds. My drone start to roll right automatically at level height and fly straight (fly away) to some where?? and uncontrollable when deactivated RTL switch to Loiture and Althold mode. End up with the tree at 8.5 m high.

Thanks for any help. :ugeek:

The cause of the crash was GPS failure.

When you switched to Loiter mode it could not do that as it requires GPS. You needed to switch to Stabilize or Altitude Hold mode.

Don’t know why the GPS failed and several times. Where you too close to the trees that it may have blocked the satellite reception?


Thanks for you advice.

We can confirm that nearest tree is >30 m away from my drone during that flight, drone and APM facing direct to the sky no any obstruction and i think it should not a problem for the APM.

one wrong thing, not only loiter mode not working when we switch to regain but AltHold mode also, still not working during it fly away. look like PWM lock and Uncontrollable. :cry:

So how is this solved?