Paired approach flight demonstration results

To increase capacity to closely spaced parallel runways (CSPR) during instrument meteorological conditions (IMC), the Paired Approach procedure has been developed. The Paired Approach procedure is a part of Interval Management (IM), which leverages automatic dependent surveillance-broadcast (ADS-B) Out for the lead aircraft (referred to as the Target aircraft) and ADS-B In for the trail aircraft (referred to as the IM aircraft). During the Paired Approach procedure, the IM aircraft uses speed commands from the flight-deck IM (FIM) equipment to maintain precise spacing between itself and the Target aircraft. The IM flight crew is given a time-based spacing parameter referred to as the assigned spacing goal, which is the desired spacing behind the Target aircraft. The desired spacing between the IM and Target aircraft in a Paired Approach operation is the spacing that will keep the IM aircraft far enough behind the Target aircraft to avoid the risk of a collision while still being close enough to the Target aircraft to avoid an encounter with its wake.The FAA successfully conducted a Paired Approach Flight Demonstration at San Francisco International Airport (SFO) and Tucson International Airport (TUS) in February, 2019. Honeywell developed the prototype avionics and Alaska Airlines, United Airlines, and Honeywell provided aircraft during the demonstration. Fourteen PA procedures (seven at SFO and seven at TUS) were performed. Overall, the FIM spacing performance was excellent: the mean spacing error at the planned termination point (i.e. the final approach fix, where closed loop spacing control ended) was -2.26 seconds, with a standard deviation of 1.15 seconds. This compares favorably with a requirement of ± 7 seconds with a 95% confidence interval. The IM pilot operational acceptability of the FIM speed guidance was rated favorably.