Analysis of Runway Safety Areas

Problem Statement and Objectives

ARA conducted airport runway safety area (RSA) research on the Airport Cooperative Research Program (ACRP) Study 04-01, one of the first studies completed under the recently created ACRP. The objective of this research was to compile and analyze historical data related to both aircraft overrun and undershoot occurrences to assist airport operators in evaluating runway safety areas. The RSA is intended to provide certain protection to aircraft in the event of an excursion from the runway during overruns, undershoots, or veer-offs.

Recent accidents involving aircraft overruns in Little Rock, AR, Toronto, ON, and Chicago, IL have focused attention on improving RSA's in the United States and elsewhere. Undershoots are also a factor in the design of or improvement of RSA's. However, many airports do not have sufficient land to accommodate standard Federal Aviation Administration (FAA)/International Civil Aviation Organization (ICAO)-recommended RSA's, or they face extremely expensive and controversial land acquisition or wetlands filling projects to make sufficient land available.

The recommended alternatives to a standard 1000-foot RSA in the United States involve either applying a runway declared distance restriction, with undesirable limitations to aircraft operational payload/range, or installing an Engineering Materials Arresting System (EMAS) with a minimum RSA length of 600 feet. Some airports cannot practically comply with either of these requirements.

Current recommendations on standard RSA length are based on a review of several overrun accidents but did not factor in variables, such as the frequency of occurrence, the presence of obstacles, existing RSA configuration, and existing operation conditions.

Results and Benefits

ARA's research provided an innovative approach to the quantitative risk assessment of RSA's for specific airport conditions. The ARA-developed risk assessment process uses historical flight and weather data, and the configuration of existing or planned RSA's, to evaluate the risk of each operation and derive its probability distribution. Based on the target level of safety established by the user, the annual number of high-risk operations at the airport can be estimated.

Other products from ARA's research included:

• A comprehensive, updated, and organized database of aircraft overrun and undershoot incidents and accidents
  
• Development of an integrated probabilistic approach for modeling the frequency, location, and consequences of aircraft accidents in the RSA
  
• Identification of causal and contributing factors to such events, for which information should be available in accident and incident reports
  
• Prototype software for risk assessment of RSA's safety