Aviation Terms->Aircraft Noise
Noise pollution produced by any aircraft or its components, during various phases of a flight: on the ground while parked such as auxiliary power units, while taxiing, on run-up from propeller and jet exhaust, during take off, underneath and lateral to departure and arrival paths, over-flying while en route, or during landing. The FAA classifies aircraft into four stages for clarification: Stage 1, Stage 2, Stage 3, and Stage 4 in order from loudest to the least noisiest. Noise levels for Stage definition of aircraft are measured at three points. These points are designed to measure noise levels for take-off, approach, and flyovers (sideline). Furthermore, classification is also based on the number of engines.