The report describes the test setup, procedure, and analysis of exhaust emissions measurement conducted on 32 commercial gas turbine engines comprised of both on-board aircraft auxiliary power and aircraft propulsion production, overhaul, and development units. The units selected are currently active in commercial airline service and thus contribute to aircraft related pollution levels. The purpose of this test was to measure exhaust emissions from auxiliary power and small aircraft propulsion gas turbines engines to establish base levels of unburned hydrocarbons, carbon monoxide, carbon dioxide and oxides of nitrogen in current existing engine designs. In addition, a survey of engine duty cycles as related to normal customer operation in the field was made to determine a typical duty cycle and the corresponding estimated level of exhaust emissions produced. (Author)