bypass ratio of 4:1. As a result, there were many technical difficulties and failures of the initial prototype hardware. However, subsequent re-designs and the incorporation of more conventional systems resulted in the engine eventually meeting the NASA requirement of thrust. To achieve the required thrust-specific fuel consumption, the EJ22 turbofan was designed as a three spool engine having a fan, two axial compressors and three expansion turbines. As a result, the engine was significantly more complicated than any prior Williams International engine. While very impressive on the test stand, the EJ22 proved quite temperamental during the two years of its development process and it was frequently subject to problems starting, overheating, part failures and various subsystem issues. Specifications References High-bypass turbofan engines 2000s turbofan engines EJ22 Three-spool turbofan engines