Since the advent of large commercial jets in the 1960s (e. g., the B707, DC8, Convair 990, and VC10), the noise profile has become an isssue for residents living in an airport vicinity. Litigation cases began to increase as a result of damages to property and health. First, the FAA and then the ICAO became involved in order to limit noise levels in a prescribed manner. Aircraft and engine designers strove to reduce or suppress noise during takeoffs and landings. Research is developing ways to reduce noise resulting from supersonic shock waves, also known as booms. Currently, there are no civil aircraft operating at supersonic speed – the Concorde was removed from service after a long operational period – partly on account of economic reasons. Supersonic aircraft are not addressed in this book; nevertheless, they fly subsonic during takeoffs and landings. References  through  may be consulted for more details on supersonic aircraft.
In the 1980s, concerns were raised on climate change to which engine emissions contribute. Again, regulatory agencies intervened to set achievable standards in order to limit pollution caused by engine exhaust gases.
The disposal of life-expired, grounded aircraft must be considered in an early design phase.
15.2.1 Materials and Structures
The choice of materials and the internal structural arrangement affect aircraft weight and cost. Materials used in the B787 made the aircraft lighter – it was a success with numerous sales even before its first flight. This demonstrates the importance of selecting appropriate materials during the conceptual design phase. The IPPD environment is a good forum in which to make choices.
15.2.2 Safety Issues
With increased passenger capacity, a quick egress is required by the regulatory agencies to ensure safety in the rare event of a fire hazard on the ground or a postcrash evacuation. The regulatory requirements stipulate a minimum number of exit doors (i. e., both main and emergency) and slides and chutes that ensure egress within a specified time. For military aircraft, the extreme measure of ejection is incorporated into design.