Aircraft Community Noise: The Revenge of a Neglected Problem

Abstract

Aircraft Community Noise has been for years a simple problem arisen only in the very last moment of the type certification of a new airplane. Just a number to be glued on the airplane, to easily comply with some bored airworthiness rule. The development of new technologies and the always more increasing interest of the local communities toward “green” requirements have moved the aircraft community noise from the desk of few researchers to the wide interest of an increasing number of people even outside the aircraft community. The consolidated reliability and the extremely high level of safety have also addressed the interest of airplane manufacturers to interior noise and comfort perception, key demanding technology issues for the direct impact on customers and community. This paper summarizes some of the activities developed in several years with reference to aircraft noise, with preferred attention to the exterior noise, being it ruled by stringent rules and certification requirements. The long, continuous and successful activity pursued by PIAGGIO Aero Industries for its P180 Avanti II airplane has been the key factor offering the opportunity for a weighted thought to the aircraft community noise problem. PIAGGIO Aero Industries currently designing, manufacturing and certifying his own products, has developed during last year’s relevant experience on both community noise and interior noise, taking advantage of strong cooperation with world-wide research organization (namely DIAS Dept. of Aerospace Design of University of Napoli “Federico II”, INSEAN Italian Institute of Naval Experience, MWL The Marcus Wallenberg Laboratory for Sound and Vibration Research Department of Aeronautic and Vehicle Engineering KTH — The Royal Institute of Technology —, NLR Netherlands National Aerospace Laboratory, DLR Deutschland Aerospace Research Center, SIRE Virtual Reality Simulation Center of University of Savona).The airplane examined is the push-propelled turboprop, three lifting surface aircraft with natural laminar flow wing P180 Avanti II. The paper summarizes numerical aero-acoustic analysis performed as basis for phenomena understanding and for comparison of the aero-acoustic behaviour of P180 novel propeller and engine exhaust design, successfully certified reaching the expected community noise reduction. The time increasing stringency of the Community Noise rules, however, is evidenced by the consideration that the problem is now also affecting small classical configuration airplanes and it cannot be neglected anymore, particularly when expecting large global market acceptance.