Detect takeoff/landing

[higfonseca]

Hey guys, how are you?
I'm trying to detect the exact moment when the user aircraft has take-off or landed, but since "ON GROUND" isn't a Simconnect event, I'm stuck on this...
What I already tried is to make a "eternal" loop, validating if the "SIM ON GROUND" variable has changed, but of course, the application almost crashed (probably due to the lack of memory).

Do you have any approaches on this?
My objective is to register the takeoff weight/fuel and landing weight/fuel with fpm on touchdown.

Thanks and happy hollidays!

 

[=rk=]

You could possibly detect undercarriage compression, or tire rotation as a transition event.

 

[DragonflightDesign]

ON GROUND not working in SimConnect is a major PITA. Another thought is to track 'SIM ON GROUND' in a gauge and send the result to your SimConnect module via a Client Event. Needs a C-gauge though.

 

[higfonseca]

I'm rewriting the app to use FSUIPC instead of SimConnect, since with this I'll be able to receive data from a variety of sims (not only P3D x64).
Thank you very much for the replies!

 

[Dave_W]

I'm glad that the OP has found a good solution to his problem.

So FWIW.

In managed code it is possible to check for SIM ON GROUND using SimConnect, at least with the FSX SP2 SDK.

The easiest way to try this, IMO, is to add this check to the SDK Managed Data Request sample and see what you get when the plane is on the ground or in the air.

 

[gaabne]

I can confirm it works fine with Simconnect on C++ (using QT). But, of course, you need to Query regularly the sim, no specific Event for it (like in Xml gauges).

 

[ChrisC]

You can also regularly poll for altitude in AGL (above ground altitude).

 

[russdirks]

I know it's an old thread, but there is a nice solution to this that nobody has mentioned: use the SIM ON GROUND simconnect variable, but don't poll it as the OP did. Instead, when you call `RequestDataOnSimObject`, set the Flags parameter to CHANGED and set the Period parameter to PER SIM SECOND, or if you want more precision, PER SIM FRAME. What that means is you will receive notifications whenever that variable changes value, so it functions a lot like an event. To see some sample code, look at the Tagged Data sample.

 

[ZenMusic]

this works

simconnect.AddToDataDefinition(DEFINITIONS.OnceTakeOff, "SIM ON GROUND", "bool", SIMCONNECT_DATATYPE.FLOAT64, 0.0f, SimConnect.SIMCONNECT_UNUSED);

simconnect.RegisterDataDefineStruct<OnceTakeOff>(DEFINITIONS.OnceTakeOff);

simconnect.RequestDataOnSimObject(DATA_REQUESTS.OnceTakeOff, DEFINITIONS.OnceTakeOff, SimConnect.SIMCONNECT_OBJECT_ID_USER, SIMCONNECT_PERIOD.SECOND, SIMCONNECT_DATA_REQUEST_FLAG.CHANGED, 0, 0, 0);