After a longer-than-expected development flight test program, during which the name Citation 500 was tried, and a number of changes to the design, the finished aircraft was debuted with the new name Citation (Model 500) and received its FAA certification in September, 1971. The aircraft was powered by two Pratt & Whitney Canada JT15D-1 turbofan engines. With fan engines, rather than turbojet engines such as powered the contemporary Learjet 25, and a straight, rather than swept wings, the Citation was over 120 knots slower than the Lear 25 (max speed of 350 kts compared with 473 kts for the LJ25), which led to nicknames such as "Slowtation" and "Nearjet", and raised eyebrows in the aviation media.