The Airlines Electronic Engineering Committee (AEEC), of the USA, was formed several years ago to promote the standardisation of communication equipment for the airlines industry. Recently the committee selected a 9.6 kbit/s coding standard for the Aeronautical Satellite Service (ASS). British Telecom Research Laboratories (BTRL), on behalf of the AEEC, acted as a processing laboratory with responsibility for the organisation and control of an international subjective test designed to select one of four candidate codecs. The test results show the subjective quality, in terms of Mean Opinion Score (MOS), attainable from Low-Rate-Encoders (LREs) operating at a bit-rate of 9.6 kbit/s [2].