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Offset 0558--true or indicated airspeed?

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43 minutes ago, airforce2 said:

In the Initial Position set facility, offset 0558 is used to set the "airspeed".  Is that TAS or IAS?

I'm pretty sure it is IAS. TAS wouldn't make sense as performance is related o IAS and that's that you'd want to control.. (The Simconnect API isn't specific).

It's probably the same as setting position, headin, speed etc in the Map.



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Thanks Pete. 

I've been experimenting with it, and it's behaving rather unpredictably...with an airliner cruising at FL320, 310 KIAS and 492 KTAS, I write a 32-bit value of 300 to 0x0558, and the airspeed tape jumps...up(?)  If I read IAS from offset 02BC soon after the write, I see values approximately 30 KIAS higher than written.

I'm refining a utility that I use for repositioning the aircraft to skip ahead on a flight plan, and just moving the jet often results in a temporary but severe over/underspeed condition at the new location due to the difference primarily with winds, but also OAT and local pressure.

It appears that correcting the current Z-axis body velocity for the delta in headwind component between old/new location and writing that back out to 3090 works better than using the IC facility. 


Bob Scott

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