ABSTRACT
The aircraft performance requirements that are incorporated in the airworthiness regulations for civil transport aeroplanes have a large effect on the design of aeroplanes and also on their safety, economical and other characteristics. These requirements determine amongst things the permissible take-off weight as a function of runway length, field elevation, obstacles, temperature, etc., thereby setting the payload capability and the range. Aircraft designs, operating procedures, etc., are usually optimised within the constraints of the performance requirements.
From pre-war arbitrary standards, the performance requirements for transport aeroplanes have evolved to a comprehensive set of rules that are largely the same in Europe and in the US. The currently applicable performance ground rules have basically been established around 1960 at the time of the large-scale introduction of the civil turbine powered aeroplanes. They have been influenced to a large extent by ICAO work (1953) on so-called rational performance requirements. In this ICAO study the relationship between the incident probability and the level of the performance requirements was analysed. The analysis was based on engine failure rates that were experienced at the time.
The intent of this paper is to draw attention to the question whether the present aircraft performance requirements provide a realistic balance between safety and economy. In the past 40 years transport aeroplanes have changed considerably. Engine reliability has improved very significantly but also the minimum acceptable safety level is nowadays higher than in the fifties. In addition to engine failure, other occurrences such as tyre failure may have to be taken into consideration. To determine which of the current performance criteria are possibly inadequate to meet the safety objectives at the turn of the century and which may be unnecessarily conservative, is considered of utmost importance for working towards a sound future development of the aircraft performance standards.
