Calling KeyStopGoHome after KeyStartAutoLanding sometimes doesn't work

[IakovlevAA]

Hi, I want to land Mavic Mini 3 Pro after I call Return to home, to prevent it from flying away. But sometimes it just stops and doesn't land. How to properly call this methods one by one?

Also calling KeyStopAutoLanding gives error

ErrorImp{errorType='CORE', errorCode='REQUEST_TIMEOUT', innerCode='FLIGHTCONTROLLER.StopAutoLanding:-3', description='null', hint='error code = -3'}

[IakovlevAA]

Just encountered situation when calling KeyStopGoHome doesn't work at all and drone is flying away

[dji-dev]

Agent comment from YIGUI LIU in Zendesk ticket #148131:

Dear Developer,

KeyStopAutoLanding is used to stop the aircraft from landing. It can only be successfully called and take effect during the landing process. If you want to stop the return-to-home process, you should call KeyStopGoHome.

For details, please refer to the API documentation:
https://developer.dji.com/api-reference-v5/android-api/Components/IKeyManager/Key_FlightController_FlightControllerKey.html#key_flightcontroller_stopautolanding_inline

https://developer.dji.com/api-reference-v5/android-api/Components/IKeyManager/Key_FlightController_FlightControllerKey.html#key_flightcontroller_stopgohome_inline

Best Regards,
DJI Innovations SDK Technical Support Team

°°°

[IakovlevAA]

KeyStopAutoLanding is used to stop the aircraft from landing. It can only be successfully called and take effect during the landing process. If you want to stop the return-to-home process, you should call KeyStopGoHome.

Yes, I know that. Problem is that it doesn't work sometimes. Also I can't sequentially execute KeyStartAutoLanding after KeyStopGoHome, it ends with drone hovering

[dji-dev]

Agent comment from YIGUI LIU in Zendesk ticket #148131:

Dear Developer,

If the drone hovers without landing when KeyStartAutoLanding is called, it may be because the landing protection has been triggered, meaning the ground is not suitable for landing.

1、You can obtain the status of the aircraft's landing protection through FlightAssistantKey.KeyLandingProtectionState, and then decide whether to call FlightControllerKey.KeyConfirmForceLanding for a forced landing.
Reference article: https://sdk-forum.dji.net/hc/en-us/articles/14253788960025-How-to-achieve-forced-aircraft-landing

2、Alternatively, you can disable landing protection via KeyLandingProtectionEnabled and call KeyStartAutoLanding again to land directly.

Best Regards,
DJI Innovations SDK Technical Support Team

°°°

[IakovlevAA]

If the drone hovers without landing when KeyStartAutoLanding is called, it may be because the landing protection has been triggered, meaning the ground is not suitable for landing.

It hovers on ~10m altitude, so it isn't the reason.

1、You can obtain the status of the aircraft's landing protection through FlightAssistantKey.KeyLandingProtectionState, and then decide whether to call FlightControllerKey.KeyConfirmForceLanding for a forced landing. Reference article: https://sdk-forum.dji.net/hc/en-us/articles/14253788960025-How-to-achieve-forced-aircraft-landing
2、Alternatively, you can disable landing protection via KeyLandingProtectionEnabled and call KeyStartAutoLanding again to land directly.

It's not about landing protection, but about sequence of executed actions.

1. Call KeyStartGoHome
2. While drone in GoHomeMode call KeyStopGoHome
3. Immediately call KeyStartAutoLanding
4. Drone hovers

Sorry, didn't guess to attach some sample earlier

if (FlightControllerKey.KeyGoHomeStatus.create().get() == GoHomeState.RETURNING_TO_HOME)
        {
            FlightControllerKey.KeyStopGoHome.create().action(onSuccess = { }, onFailure = { e -> print(e) })
            val begin = System.currentTimeMillis()
            while (FlightControllerKey.KeyGoHomeStatus.create().get() != GoHomeState.IDLE)
            {
                if (System.currentTimeMillis() - begin > 2000) return false
            }
        }

        FlightControllerKey.KeyStartAutoLanding.create().action( onSuccess = { }, onFailure = { e -> print(e) })

[dji-dev]

Agent comment from YIGUI LIU in Zendesk ticket #148131:

Dear Developer,

Your code doesn't seem to have any issues. Did calling KeyStartAutoLanding return any errors? If there are no errors, it's more likely an issue with the aircraft itself or the environment rather than your program.

Can you successfully land the aircraft by performing the same operation using the DJI Fly app? If it's not because the area below the aircraft is unsuitable for landing, another possibility is that the downward vision system triggered a false obstacle avoidance, which prevents landing. This can happen in environments with strong light, low light, reflected light, or if the obstacle avoidance camera is not clean.

Best Regards,
DJI Innovations SDK Technical Support Team

°°°

[IakovlevAA]

Did calling KeyStartAutoLanding return any errors?

Actually, no. It always return no errors

If there are no errors, it's more likely an issue with the aircraft itself or the environment rather than your program.

I tried this in simulator, and the problem is that there is 20% chance that successful call will have no impact on drone and it will hover. Also, there is no sound from RC about landing, so I assume that KeyStartAutoLanding didn't work

Can you successfully land the aircraft by performing the same operation using the DJI Fly app?

Yes I can, also I can perform successful landing by using sample above

[dji-dev]

Agent comment from YIGUI LIU in Zendesk ticket #148131:

Dear Developer,

If the Fly app and sample code can achieve a successful landing, it indicates that there should be no issue with the aircraft itself.

You can only compare the differences between your own code implementation and the sample implementation, then make more attempts to identify the patterns and causes behind the failure to land, or add more retry mechanisms at the code level.

Best Regards,
DJI Innovations SDK Technical Support Team

°°°