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An evaluation was made of advanced technology engine cycles, low emissions combustors and low noise exhaust nozzles which identified payoffs for advanced propulsion technology in terms of aircraft gross weight, stratospheric cruise emissions and airport noise reduction. Two types of variable cycle engines were studied; turbine bypass engine (TBE) and variable stream control engine (VSCE). Results of the study showed the TBE is clearly superior to the VSCE for Mach 2.4 and Mach 3.2 cruise. Critical component technologies which must be developed and validated before full scale engine development were also identified on the basis of system viability, technological challenges and degree of risk.

Commercial airline cockpit crews flying transoceanic routes were tested repeatedly with a battery of cognitive tests implemented on a lap-top microcomputer. Testing was conducted before departure and during the early, middle, and late periods in flight on the outbound leg of four flight pairings. The same tests were administered on the return leg(s) of each flight pairing but, just prior to final administration of the tests, six minutes of moderate resistance exercise was undertaken by the Captain and one other pilot (either the First or Second Officer). The remaining officer substituted a walk around the aircraft cabin for exercise and served as a control. The same Flight Captain was available for testing on all flights (N = 22), but due to scheduling requirements, the same First and Second Officers were available for 4-8 flights each. Comparisons were made between the two exercise conditions over all test sessions, but no statistical relationships were found.

The National Aeronautics and Space Administration (NASA) is engaged in a Supersonic Cruise Airplane Research (SCAR) Program to study and experimentally evaluate advanced technology that is applicable to future supersonic transports. A broad spectrum of advanced engine concepts including Variable Cycle Engines (VCEs) has been evaluated by Pratt & Whitney Aircraft (P&WA) in conjunction with the SCAR Program. This paper describes some of the advanced engine concepts and VCEs that were evaluated, and summarizes the features and problems of each engine. Based on the results from this study, one engine has been identified as being the most promising, the Variable Stream Control Engine (VSCE). It has the potential to significantly reduce jet noise and to improve airplane performance relative to first-generation supersonic transport (SST) engines.