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Metering air traffic requires aircraft to delay their flyover time at designated enroute fixes. This paper presents an analysis of achievable airborne delays by speed control. To ease real-world implementation, current practices set the same achievable airborne delay to all flights flying the same airway, instead of customizing the achievable delay for each flight. Using past actual radar track and flight data, the achievable delay and its potential compliance rate are analyzed statistically through illustrative numerical simulations for the international arrivals at the Tokyo International Airport. In addition, the potential benefits of fuel savings by speed control are also investigated. Simulation results indicate that 2-4 min delays per 30 min flight time are achievable on average with high compliance rate and 2-3% fuel savings are potentially expected by speed control despite the flight time increase. The analysis conducted allows decision makers to set appropriate achievable airborne delay values to each airway for real operations. INDEX TERMS Air traffic control, air traffic flow management, air transportation, calculated time over, speed control, trajectory-based operations.

Modern airliners use the profiles calculated by the onboard flight management system (FMS) to execute safe and efficient descents. Since the wind often varies greatly between the cruising altitude and the end-of-descent altitude, the FMS uses both predicted and measured wind to determine the descent profile. Even so, the actual wind encountered along the descent changes the profile. When a constant descent speed is maintained at idling thrust, the aircraft deviates from its path and needs to either fly an additional steady level flight segment to the metering fix or deflect speed brakes to ensure the speed constraints at the metering fix are met. This research analyses the optimal top of descent in respect to such wind prediction error and fuel burn. Numerical simulations for the Boeing 767-300 are done and it is shown that an early descent of 0.5 nm would save, on average, 0.9 lb of fuel for an idling descent from 30,000 ft to 10,000 ft and at a constant speed of 280 kt, and decrease the number of cases where the necessary deceleration could not be achieved due to lack of enough lateral distance by 77%, thus improving safety and easing operations.

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