Research On Equivalent Test Method Of Aircraft Noise Airworthiness Lateral

With the improvement of environmental awareness and aircraft design level,aircraft airworthiness noise certification standards have become increasingly stringent,resulting in a series of problems such as rising costs and prolonging the cycle.In order to promote the development and innovation of noise qualifying technology,ICAO put forward the concept of equivalent procedure.However,ICAO has only given the basic concept of equivalent procedure,and has not given specific test plans.Therefore,the practical application of equivalent procedures in airworthiness certification has yet to be studied.According to the research idea of airworthiness compliance verification,the method of noise prediction is adopted to realize the application of equivalent procedures.Taking the Boeing 737-800 passenger aircraft as an example,according to the noise prediction method provided by the semi-empirical tool ANOPP,the prediction algorithms of engine noise and airframe noise were programmed respectively,and the prediction value of engine noise and airframe noise were obtained by using the built aircraft noise prediction platform.Then use the noise superposition principle to integrate the engine noise and the airframe noise,and find the total noise of the aircraft at the lateral noise measurement point.Finally,the airworthiness of the aircraft lateral noise is evaluated,and the equivalent cut-in interval when the aircraft uses the track cut-in method is obtained according to the noise evaluation calculation results.The calculation results show that when the aircraft uses the track cut method to fly,the aircraft cuts into the track at a position 89 meters above the ground and then starts to fly along the track,and leaves the track at a position 563 meters above the ground.The range formed by the entry and exit points of the equivalent cut-in interval and the lateral noise measurement point is between 23.5° and 162.0°,so this range can be used as a reference interval for the equivalent test method to verify the feasibility of the equivalent test method.