En-route flight deck-based merging and spacing impact on flight crew operations

In an effort to achieve consistent, low variance spacing between aircraft pairs during arrival operations and to reduce aircraft maneuvering, noise, fuel burn, and controller workload, the Federal Aviation Administration (FAA) is developing, and UPS plans to implement, an Automatic Dependent Surveillance-Broadcast (ADS-B) concept termed Merging and Spacing (M&S). M&S has two phases: a strategic set-up by a ground operator followed by tactical Flight Deck-Based Merging and Spacing (FDMS). Both phases, in the initial implementation, involve pilots being requested to fly speeds from sources other than Air Traffic Control (ATC). In FDMS, the speeds are generated and displayed on-board the aircraft via a Cockpit Display of Traffic Information (CDTI) or other display. The flight crew follows those speeds to achieve a desired time interval from a lead aircraft. This paper focuses on FDMS and presents the subjective and objective results of a human-in-the-loop simulation that examined FDMS from the flight crew perspective during a merge in the en-route environment. Termed FDMS 2, the simulation is part of a development and maturation process that is underway for FDMS. The simulation examined the impact of FDMS on: concept and display acceptability; workload and situation awareness; and procedures for non-normal situations. Ten airline-qualified pilots flew a series of scenarios while acting as the pilot flying. Results indicated general acceptability and improvements over current-day operations under normal and non-normal conditions. Pilots, on average, found the number of speed commands acceptable and their traffic awareness to be improved. They reported a small and acceptable increase in workload over current conditions. The majority of pilots reported concerns about the location of the CDTI, but all agreed that having the display in the experimental location was preferable to not having it and not being able to conduct FDMS. It was also found that pilots may have been driven to spend higher amounts of time viewing a display to detect situations that normally would be resolved by ATC. These results will be used to further refine FDMS and to focus future simulations as the application moves toward operational approval.