A Review of Transport Airplane Performance Requirements Might Benefit Safety

FLIGHT SAFETY FOUNDATION FEBRUARY 2000 FLIGHT SAFETY DIGEST A Review of Transport Airplane Performance Requirements Might Benefit Safety o n t i A AV i a u A L I A v t R T h I E O A o D N E r F t i t n i i JAA e o A s J D N M O I I N T E I A u r o p e S T R FLIGHT SAFETY FOUNDATION For Everyone Concerned with the Safety of Flight Flight Safety Digest Officers and Staff Vol. 19 No. 2 February 2000 Stuart Matthews Chairman, President and CEO Board of Governors In This Issue Robert H. Vandel A Review of Transport Airplane Executive Vice President 1 James S. Waugh Jr. Performance Requirements Might Treasurer Benefit Safety Carl Vogt General Counsel and Secretary Most current performance requirements for the certification Board of Governors and operation of transport category airplanes were ADMINISTRATIVE established at the beginning of the jet age. Today, operating Ellen Plaugher experience and data provide the most accurate means to Executive Assistant further improve the performance requirements of modern Linda Crowley Horger transport airplanes. Office Manager FINANCIAL Bird Strikes Found Most Common at Elizabeth Kirby Low Altitudes in Daylight 15 Controller TECHNICAL Data show 52,663 bird strikes worldwide from 1988 through James Burin 1998. Director of Technical Programs Joanne Anderson FAA Publishes Guidelines for U.S. Technical Assistant 17 Ann Hill Aircraft Operators Planning Service in Manager of Seminars and Workshops Canada, Mexico Robert H. Gould Managing Director of Aviation Safety Audits The information was developed under terms of the North and Internal Evaluation Programs American Free Trade Agreement. Robert Feeler Manager of Q-STAR Program Bird Strike Prompts Airplane’s Return to Robert Dodd, Ph.D. 19 Manager, Data Systems and Analysis Departure Airport Darol V. Holsman Manager of Aviation Safety Audits MEMBERSHIP Carole L. Pammer Director of Marketing and Business Development Ahlam Wahdan Assistant to the Director of Marketing and Business Development PUBLICATIONS Roger Rozelle Director of Publications Mark Lacagnina Senior Editor Wayne Rosenkrans Senior Editor About the cover: Transport airplane certification performance requirements are Linda Werfelman contained in European Joint Aviation Requirements (JARs) 25 and in U.S. Federal Senior Editor Aviation Regulations Part 25. (Illustration by FSF Production Staff) Karen K. Ehrlich Production Coordinator Flight Safety Foundation is an international membership organization Ann L. Mullikin dedicated to the continuous improvement of aviation safety. Nonprofit and Production Designer independent, the Foundation was launched officially in 1947 in response to Susan D. Reed the aviation industry’s need for a neutral clearinghouse to disseminate objective Production Specialist safety information, and for a credible and knowledgeable body that would identify threats to safety, analyze the problems and recommend practical David A. Grzelecki solutions to them. Since its beginning, the Foundation has acted in the public Librarian, Jerry Lederer Aviation Safety Library interest to produce positive influence on aviation safety. Today, the Foundation provides leadership to more than 850 member organizations in more than 140 Jerome Lederer countries. President Emeritus A Review of Transport Airplane Performance Requirements Might Benefit Safety Most current performance requirements for the certification and operation of transport category airplanes were established at the beginning of the jet age. Today, operating experience and data provide the most accurate means to further improve the performance requirements of modern transport airplanes. Joop H. Wagenmakers The performance requirements of U.S. Federal Aviation In the period since the current performance requirements and Regulations (FARs) Part 251 and European Joint Airworthiness operating requirements for turbine-engine transport airplanes Requirements (JARs) 252 have a substantial effect on the design, were adopted, considerable operational experience has been operating economy and safety of transport category airplanes. gained, and significant improvements have occurred, for example, in engines, airplane systems, maintenance procedures Performance requirements are minimum standards that must and runway surfaces. Moreover, the minimum operating safety be met during airplane certification and operation. The level that the industry, the regulators and the public currently requirements affect variables such as stall speeds, takeoff and regard as acceptable is higher than it was in the 1950s. landing speeds, takeoff and landing distances, climb gradients, etc. The performance requirements determine, for example, The industry might be resistant to change current performance the permissible takeoff weight for conditions that include requirements, which are working reasonably well. Nevertheless, runway length, obstacles, field elevation and air temperature, the industry should consider the long-term benefits to safety thereby setting the airplane’s payload and range. Airplane and to operating economy that could be derived from a review design features and specific airplane operating procedures to fine-tune the performance requirements. usually are optimized by airframe manufacturers within the constraints of the performance requirements. Jet Age Brings Changes The performance requirements have evolved from rudimentary The transport airplane performance requirements in U.S. Civil standards established before World War II to relatively Air Regulations (CARs) Part 4b3 were applied during the comprehensive standards that are similar in the United States certification of the Convair 240 and 340; the Douglas DC-4, and in Europe (see “ Summary of Transport Category Turbine DC-6 and DC-7; the Lockheed Constellation series; and other Airplane Performance Standards and Operating Standards,” U.S. reciprocating-engine airplanes that transported most page 10). passengers and cargo during the 20 years after World War II. The performance requirements in CARs 4b and the Most of the currently applicable performance requirements performance requirements established by the United Kingdom were established in the late 1950s, at the beginning of the large- also were used to certify transport airplanes designed and built scale introduction of turbine airplanes into commercial service. in many other countries. FLIGHT SAFETY FOUNDATION • FLIGHT SAFETY DIGEST • FEBRUARY 2000 1 These performance requirements were unsuitable for certifying reciprocating-engine airplanes are in FARs 121.175 through jet aircraft. Work to revise the performance requirements was 121.187, and are in the JARs commercial-airplane-operating conducted initially in the United Kingdom, and the work was requirements (JAR–OPS 1). continued by the International Civil Aviation Organization (ICAO) Standing Committee on Performance (SCP). Many of CARs 4a, the U.S. certification requirements adopted in 1950 the SCP’s ideas4 were used in the development of FARs 25 for normal, acrobatic and transport category airplanes, specified and JARs 25. a maximum stall speed.5 The premise for the maximum-stall- speed requirement was that airplanes with higher stall speeds The statistical database used in the SCP studies now is outdated, — thus, higher takeoff speeds and higher landing speeds — and experience in the past 40 years with the operation of would have longer takeoff distances and longer landing turbine-engine transport aircraft has taught the aviation distances, and would have a greater risk of an accident during community many lessons. takeoff or landing. This premise is the basis for the 61-knot maximum stall speed incorporated in FARs 23 and JARs 23, Lessons Learned from Accidents the certification standards for normal, utility, acrobatic and commuter category airplanes. The investigations of many performance-related airplane accidents in the late 1940s revealed that the unreliability of CARs 4b, which in 1953 superseded the CARs 4a certification some engines was a major factor in the accidents. requirements for transport category airplanes, did not specify maximum stall speeds. CARs 4b, however, retained minimum- Another major factor involved in accidents during the period climb-performance requirements that caused airplane was performance degradation caused by high outside air manufacturers to use relatively low stall speeds when temperature. Adjustment of takeoff weight to compensate for optimizing their designs. The minimum-climb-performance performance degradation caused by high temperature was not requirements were expressed as: required rate of climb = required then, because regulators and manufacturers believed constant x (stall speed)2. Different values for the constant were that the performance requirements included margins adequate specified for different airplane configurations and phases of to compensate for performance losses caused by temperature. flight. The accidents showed the need to correct for the effects of high Some ICAO delegates in the early 1950s said that the rate-of- temperature. A requirement for temperature accountability was climb requirements were not suitable for jet airplanes, and added to CARs 4b in the early 1950s. The rule required they recommended a review of the climb-performance manufacturers to determine the effects of all expected operating requirements. Climb-gradient requirements were regarded as temperatures on airplane aerodynamic characteristics and on more appropriate and logical, because climb-gradient engine power, and to include in

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