This article defines and elaborates on “AIR GROUND”, a derived parameter typically based on Left Gear WOW or other WOW parameters dependent upon recorded parameter availability.

Air ground is a discrete binary parameter measuring whether an aircraft is airborne or on the ground using the landing gear’s weight sensors. The “Left Gear WOW” is used as a default with the left distinction being in-line with the Scaled Analytics standard. WOW refers to the weight-on-wheels, which indicates whether the landing gear is supporting the weight of the aircraft or not. By monitoring the specific landing gear's WOW status, the overall airborne status of the aircraft can be determined.

Recorder Value

Air Ground being a discrete binary parameter measures two values:

1 = On Ground

0 = In Air

The value used in the AIR GROUND event definition is 0.5. With events triggering at ‘AIR GROUND > 0.5’ or ‘AIR GROUND <0.5’. This value is chosen because of the recording frequency of the "Left Gear WOW" parameter and the transition that occurs between values at recorded points. By setting the event definition value as 0.5, SkyAnalyst can detect events during the plot transition period. This is useful during instances when the aircraft is transitioning during takeoff and landing, where there may be discrepancy between main landing gear and nose landing gear.

Figure 1: AIR GROUND and Radio Height plotted parameters in Sky Analyst