Flight deck crew experiences flying profile descents during metering operations

NASA’s Air Traffic Management Technology Demonstration #1 Project has a goal of improving airport capacity by developing and testing ground and flight deck tools for the terminal airspace. The Controller Managed Spacing (CMS) suite of tools has been developed to maintain high traffic density for aircraft on optimal profile descents on area navigation routes. Several studies have examined the controllers ’ interaction with CMS, but there has only been one study that explored the impact of this toolset on pilots. This human-in-the-loop simulation is the second to focus on the impact of CMS on the flight deck. Twelve Boeing 737-800 qualified flight crews flew a glass cockpit simulator with the flight management system and flight dynamics of a B737-800 aircraft. Crews flew four scenarios in the Phoenix Terminal Airspace that included clearances to descend on a profile, which was adjusted almost exclusively with speed changes. Two variables were manipulated: speed changes and ATC phraseology. Workload and questionnaire data indicate that scenarios with clearance speeds faster than the route restrictions were more challenging. The phraseology of the speed clearances had an impact upon pilot workload and the efficiency of the profile descent, as determined by the number and duration of flight level-offs. Finally, the time variation to fly the descent illustrated the potential for disrupting ground scheduling tools in the terminal area