XPLM_API int        XPLMAcquirePlanes(
                         char **              inAircraft,    /* Can be NULL */
                         XPLMPlanesAvailable_f inCallback,    
                         void *               inRefcon);    

typedef struct {
     /* The size of the draw state struct.                                         /
     int                       structSize;
     / A ratio from [0..1] describing how far the landing gear is extended.       /
     float                     gearPosition;
     / Ratio of flap deployment, 0 = up, 1 = full deploy.                         /
     float                     flapRatio;
     / Ratio of spoiler deployment, 0 = none, 1 = full deploy.                    /
     float                     spoilerRatio;
     / Ratio of speed brake deployment, 0 = none, 1 = full deploy.                /
     float                     speedBrakeRatio;
     / Ratio of slat deployment, 0 = none, 1 = full deploy.                       /
     float                     slatRatio;
     / Wing sweep ratio, 0 = forward, 1 = swept.                                  /
     float                     wingSweep;
     / Thrust power, 0 = none, 1 = full fwd, -1 = full reverse.                   /
     float                     thrust;
     / Total pitch input for this plane.                                          /
     float                     yokePitch;
     / Total Heading input for this plane.                                        /
     float                     yokeHeading;
     / Total Roll input for this plane.                                           */
     float                     yokeRoll;
} XPLMPlaneDrawState_t;