When the Williams International FJ44 turbofan engine was introduced in the late 1990’s, it established a new standard for efficiency and power. Sierra Industries immediately launched a program to certify the FJ44-2A for re-engining the Citation I. Offering as much as 25% greater fuel efficiency and dramatic across-the-board performance increases, the FJ44 Eagle II was certified in 2002 and its sibling, the Stallion, in 2006. To date, some 40 Citation I aircraft have been re-engined, accumulating well over 15,000 trouble-free flight hours.
Citation re-engining programs now include the original FJ44 Eagle II and FJ44 Stallion upgrades for the 500/501SP and the newest, the FJ44 Super II modification for the Citation 550 (featuring Williams FJ44-3A turbofan engines). All these programs refit legacy Citations with state-of-the-art Williams FJ-44 powerplants, dramatically boosting performance throughout the flight envelope. Both the Eagle II and Stallion have current FAA and EASA approval, and FAA approval for the Super II was received in early 2009.
The Super II program has its roots at Sierra Industries in the early 1980’s when they did research to upgrade the Citation II (550) from the Pratt JT15D-4 engine to the -5 engine. This program went idle until the late 1990’s when they started the first Williams re-engining for the Eagle II. The Super II re-engining program fits 2,820 lb. thrust Williams FJ44-3A engines to the Citation II airframe, adding 400 NM range and providing substantial increases in speed, climb performance, maximum fuel payload and fuel efficiency.
Following shortly after Super II certification, is the Sierra Super S-II, a re-engined Citation S-II (S550) with Williams FJ44-3A powerplants. With performance improvements comparable to the Super II, this aircraft will boast a range of up to 2,300 nautical miles, climb to FL430 in under 25 minutes and achieve cruise speeds up to 420 KTAS.