Clifford Development has certified 35 improvements as part of a recently issued STC, including: an Ametek digital engine display, heavy duty BFG brakes and a dual FADEC system certified to July 2007 standards. The Williams FJ44-3A engines are thermodynamically rated at 3,000 lbs. (with takeoff flat-rated thrust of 2,820 lbs.) versus the original engine’s 2,500-lbs. rating. With this modification, the typical Citation 550/S550’s basic operating weight is reduced 250 lbs.