A Development Method and Applications of the Most Severe Engine Parameters for Airworthiness Certification

Abstract

For commercial aircraft engines, airworthiness certification is essential and the very first step before entry into service. Airworthiness requirements mainly consider the safety of the aircraft and mandate the aviation products to safely operate under all possible conditions. Therefore, during an airworthiness certification process, the relevant analyses and verifications are generally carried out by considering the most adverse operating conditions. A method for obtaining the most severe engine parameters which represent the possibly most adverse conditions is presented in this paper. Furthermore, it is used to complete the calculation of a set of most severe parameters, including rotor speed, turbine temperature, pressure, shaft torque, etc. Finally, this paper describes applications of these most severe parameters in the certification of the engine airworthiness regulation-CCAR/FAR33. Two examples are provided to illustrate the difference between using the general parameters and the most severe parameters. These examples demonstrate that application of most severe engine parameters to comply with the airworthiness requirements is the most practical way to guarantee the true safety.