Improving Aircraft Sequencing and Separation at a Small Aircraft Transportation System Airport Conference Paper uri icon


  • Ever-increasing traffic levels at the nation's major airports have led to traffic congestion and flight delays. Capacity must be increased by building more airports at a great cost or by expanding services to some of the 4,500 airports not currently served by scheduled air carriers. A system must be developed to handle the increased traffic at these non-controlled airports, especially when instrument meteorological conditions prevail. Much work has been performed under the NASA Small Aircraft Transportation System program to determine the feasibility of aircraft operation under instrument flight rules in an air-traffic control free environment. This paper presents research, performed as an extension of the SATS program, into self-separation of general aviation aircraft in a self-controlled airport environment. The research focused on two specific areas: (1) improving automatic sequencing of aircraft of different speeds to make the airspace more efficient, saving time, fuel, and money, and (2) assisting the pilot with approach timing decisions to assure safe aircraft spacing while proceeding in an efficient manner. The primary evaluation method was a real-time distributed simulation with test cases performed by multiple pilots flying simultaneously in the simulation environment. Simulations and test scenarios were performed in the Engineering Flight Simulator, a modular, real-time, nonlinear, six degree-of-freedom fixed base simulator, at Texas A&M University. The pilots flew various general aviation aircraft with differing approach speeds under instrument meteorological conditions. Approach speeds ranged from 80 kts. to 140kts. to encompass the majority of aircraft from small trainers up to light jets that will use the potential SATS airports. New spacing rules were implemented to reduce holding times, and Total Holding Time was used as a metric to validate these new rules. Simulations were performed both with and without automated sequencing to validate the new spacing rules and compare the effects of automated sequencing. A human factors analysis was performed to determine the benefits of shifting some spacing functions from the pilot to the onboard systems, and reductions in pilot workload and improvements in pilot performance were measured to assess the safety improvements due to the increased automation. Based on the results presented in the paper, it was concluded that by changing the sequencing procedure to assign airspace entries once the aircraft are closer to the airport, potential bottlenecks can be avoided and holding times reduced. Furthermore, as a result of the increased avionics functionality and a change in approach spacing guidelines, safety is improved, and holding times are reduced. With these two improvements combined, significant holding time reductions are achieved resulting in fuel and cost savings and further make the self-controlled airport a safe and viable transportation alternative.

name of conference

  • AIAA 5th ATIO and16th Lighter-Than-Air Sys Tech. and Balloon Systems Conferences

published proceedings

  • AIAA 5th ATIO and16th Lighter-Than-Air Sys Tech. and Balloon Systems Conferences

author list (cited authors)

  • Helbing, K., Spaeth, T., & Valasek, J.

citation count

  • 2

complete list of authors

  • Helbing, Kyle||Spaeth, Theresa||Valasek, John

publication date

  • September 2005