Re-engining at Sierra has encompassed several levels of improvement to the stock Cessna Citation aircraft, ranging from simple and inexpensive updates to the Pratt JT-15D to complete replacement with Williams FJ44-series engines. Not long after acquiring the EAGLE and LONGWING STC’s for the Citation 500/501SP, Sierra began offering upgrades of the original JT-15D-1 engine to -1A and -1B specs, providing up to 20% improvement in thrust at cruise altitudes. (LINK)

Sierra’s first engine replacement program, called the Eagle 400, was awarded an STC in 1992. This modification replaced the original Pratt & Whitney JT-15D-1 series engines with JT-15D-4 engines (the original Citation II engine) and added an increase in Gross Takeoff Weight to 12,500 lbs. With an increase in thrust from 2,200 lbs. to 2,500 lbs. the Eagle 400 provided a significant improvement in climb performance and cruise speed over the stock Citation I.

When the Williams International FJ44 turbofan engine was introduced in the late 1990’s, it established a new standard for efficiency and power. Sierra 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.

Sierra’s Citation re-engining programs now include the original FJ44-2A Eagle II and Stallion upgrades for the 500/501SP, the FJ44-3A Super II modification for the Citation 550 and our newest, the FJ44-3A Super S-II for the Citation S550 model. All these programs refit legacy Citations with state-of-the-art Williams FJ44 powerplants, dramatically boosting performance throughout the flight envelope. All have current FAA approval, and the Eagle II, Stallion and Super II are also EASA-approved. EASA approval is pending on the Super S-II and is expected in Q4 of 2009.

Sierra’s Super II/S-II program has its roots at Sierra in the early 1980’s when we did research about upgrading the Citation II (550) from the Pratt JT15D-4 engine to the -5 engine. This program went idle until the late 1990’s when we started the first Williams re-engining for the Eagle II. This re-engining program fits 2,820 lb. thrust Williams FJ44-3A engines to the Citation II and S-II airframes, adding up to 400 NM range and providing substantial increases in speed, climb performance, maximum fuel payload and fuel efficiency.

The Sierra Super S-II, a re-engined Citation S-II (S550) with Williams FJ44-3A powerplants is our most recent upgrade program. 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.