Less than 11 months after first flight and a year and a half of design, engineering and test flights, the FAA has awarded Sierra Industries, Ltd. STC ST09559AC Approved Model Listing (AML) for their Citation 550-based Sierra Super II modification.

The Sierra Super II modification upgrades the Citation II’s performance by re-powering the aircraft with Williams International’s FADEC-controlled 2820 lb. thrust FJ44-3A engines. Williams’ high-performance FJ44-series turbofan engines are currently utilized on more than 20 different business jet designs. Sierra Industries is the ONLY non-OEM company to receive FAA certification to install Williams engines on a certificated aircraft, with a current offering of 6 different models of FJ44-powered aircraft.

As of this writing, the company has 6 Sierra Super II aircraft in current production at its facilities in Uvalde, Texas, with an order book stretching well into 2009. Sierra’s test pilots flew the aircraft the equivalent of some 1-1/2 times around the globe, verifying the Sierra Super II’s performance and reliability. During 87 test flights totaling 123 hours of flying time, the Super II test aircraft achieved its projected top speed of 404 KTAS and demonstrated altitude performance at 50,000 feet. The Super II STC includes all the latest FAR amendments and is fully Stage IV noise compliant.

The Super II provides an 'across-the-board' performance enhancement for the Citation II – boosting fuel efficiency and reducing carbon emissions by as much as 27%, cutting time-to-climb to under 25 minutes to FL430, extending range to nearly 1800 NM, and increasing maximum fuel payload. Dramatic reductions in takeoff field length (more than 20% reduction at 5000 ft., ISA +20º), coupled with increased climb rates make the Super II a superb all-around performer for virtually any field conditions or altitude. Dual Channel FADEC controls provide smooth, vibration-free flight for passengers and a reduced workload for the pilot.

Building on Sierra’s 25 years of Citation modification history and 15 years of experience in Citation re-engining, the Super II development program has been leveraged on the FAA and EASA-approved Eagle II and Stallion modifications, which also feature Williams International FJ44 advanced turbofan engines. The Super II modification extends Sierra’s history of producing more than 40 FJ44 re-engined Citations since 2002.

Sierra Industries has specialized in Citation aircraft for nearly 30 years and holds more than 75 proprietary Citation modifications and company total of 300 FAA STCs. Sierra is a wholly owned subsidiary of The SkyWay Group, Inc., which owns a business portfolio of six aviation related companies, including FlighTime Business Jets and the Uvalde Flight Center.

Next; Sierra’s newest re-engining program involves adding the 2820 lb. thrust Williams FJ44-3A engines to the Cessna S550 Citation S-II model. With its supercritical wing design, the FJ44-powered Sierra Super S-II promises improvements in across-the-board performance. The Super S-II program is well underway with FAA approval expected to follow shortly after the Super II STC.

FMI: www.sijet.com