| Description | Aircraft chapter code. Defines an aircraft type in terms of its certificated noise level. For example, chapter 2 aircraft are characterised by the noisier, low bypass turbofan aircraft and early high bypass turbofan aircraft; chapter 3 aircraft are characterised by the modern, quieter, high bypass turbofan aircraft; chapter 4 aircraft are aircraft which are likely to have previously been classified as chapter 3 but are deemed to have met even more stringent standards. Note: chapter 1 is not an official classification but is / was sometimes used to indicate excessively noisy (e.g. older) aircraft, for example Concorde. Allowable values defined in aircraft chapter reference data table. |
|---|
