THIS paper describes the equipment and specific technique used for rapidly determining the shape and location of the compressor stall area. Complete fuel feed analysis for optimum performance operation at sea level can be accomplished in 4 hr. Information is presented on the tests conducted to date, and the general trends observed regarding compressor stall.The instrumentation used consists of a direct writing rectilinear plotting board and a universal electronic fuel control. The fuel control permits the selection of any desired acceleration fuel schedule and thus provides a medium for an exact examination of engine characteristics.When selecting an acceleration fuel schedule, consideration must be given to the shift in the stall area caused by throttle manipulation and past engine history. Illustrations are presented to show the variation between ideal and practical fuel schedules.The effect of ambient temperature on compressor stall is discussed. Theories on steady-state fuel flows have been substantiated, but some question exists as to the validity of computation under transient conditions. Comparison is made between the calculated and measured fuel flows for two modern axial-flow-type engines.