Purpose: In the past, Airport Traffic Control Tower (ATCT) siting decisions have been significantly influenced by the upper height limits imposed by terminal procedures (TERPS) and controller opinions. Because tower siting (height and location) affects airport safety and construction costs, the FAA had no means to measure quantitatively the improvement in air traffic controller visibility that can be gained by changing the tower height and location on the airport surface, and there was no required minimum criterion for tower height.

Background: FAA human factors specialists (ATO-P R&D) and Airport Facilities Terminal Integration Laboratory (AFTIL) personnel created and conducted tower siting simulations of different existing towers to establish a performance baseline of a controller's ability to detect and identify aircraft on the airport surface at distance points. Research results were used to determine requirements for future tower construction projects, ensuring safe minimums and constraining costs of the nation's airport investments. Prior to the simulation, human factors researchers refined and validated an experimental approach and methodology to evaluate the human performance characteristics affecting tower siting decisions.

This effort supports the FAA Flight Plan Goals for Increased Safety regarding the FAA Safety Management System (SMS) initiative to update the FAA Order for tower siting; establishes quantifiable measures of human performance for tower siting decisions; and leverages work on the probability-of-discrimination (detection, recognition, and identification) done by the Army Research Laboratory in Adelphi, Maryland. The visibility analysis tool that was created by this effort generates probability of discrimination curves and assesses the impact of tower height on visibility. The visibility analysis tool is available on the Internet to all tower siting project teams and is being used by them in planning for new control towers.

diagram of Tower to key Point Distance with crucial points of interest including Line of sight angle of incidence, key point, corrected observation height from top observation deck to ground