Introduction

The air transportation system in the United States is safer than comparable modes of public transportation. For major airlines (i.e., air carriers operating under Part 121 of the Federal Aviation Regulations [FARs]), the average number of fatalities per 100 million passenger miles is about 0.7, compared to about 1.8 for automobiles, about 11 for intercity buses, and about 17 for trains (BTS 1998a, 1998b, 1998c, 1998d; NHTSA, 1996). In terms of safety, travel on major airlines within the U.S. is matched only by travel on major airlines in other highly developed countries. Nevertheless, fatal accidents are always tragic, and complacency on the part of the FAA or industry is not an appropriate response. In fact, the FAA has already established a strategic goal of zero accidents.

The Federal Aviation Administration (FAA) plays a major role in promoting aviation safety.¹ However, the FAA will face several important challenges in the future. If the aircraft accident rate remains constant or slowly decreases, the annual number of accidents will swell as the number of flights increases to meet consumer demands. The public has the right to expect high levels of safety, and it is incumbent upon industry and the FAA to improve the effectiveness of their safety programs. In part, this means reacting to major accidents by taking aggressive action to prevent similar accidents, but without detracting from ongoing safety programs to address other risks.

Almost all aircraft accidents are caused by a chain of events, the elimination of any one of which could have prevented the accident. The most common link in these chains involves human factors (pilots, air traffic controllers, maintenance crews, etc.). However, in some cases, one or more links in the accident chain are associated with the design of the aircraft. Either a design deficiency results in an equipment malfunction that leads to an accident, or a design enhancement could have prevented an unexpected event from resulting in an accident.

The FAA's Aircraft Certification Service (AIR)² is responsible for promoting the safety of new aircraft by certifying that they meet established safety standards. Certification includes type certificates (certification of all-new aircraft designs), amended type certificates (certification of derivative aircraft designs based on previously certificated products), production certificates (certification of a manufacturer's ability to produce aircraft in conformance with a certificated design), and airworthiness certificates (certification of the airworthiness of each newly manufactured aircraft). AIR also promotes the continued airworthiness of existing aircraft by mandating modifications when operating experience indicates the presence of a real or potential hazard.³

As part of the FAA's efforts to improve aviation safety, AIR chartered the National Research Council to examine safety-related elements of the certification and continued air-worthiness process and to recommend an approach to improve AIR's risk evaluation and risk management. In response, the National Research Council's Aeronautics and Space Engineering Board formed the Committee on Aircraft Certification Safety Management. This report is the result of the study conducted by that committee. A complete list of the committee's findings and recommendations appears in Appendix A.

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