Sierra Industries (static display) is debuting its Sierra Super S-II after the modified Citation made its first flight on September 26.

The Super S-II flew for 36 minutes at Sierra’s Uvalde, Texas modification center and is the company’s latest Williams re-engine modification program.

The Super S-II uses the dual FADEC Williams FJ44-3A engines to increase performance to the Cessna Citation S-II (Model S550). The extra power from the new engines meant the aircraft climbed to 18,000ft in just 3min 45sec. Sierra’s CEO and chief test pilot Mark Huffstutler says: “This was a superb first flight. Everything worked so well, it seemed almost routine. There is no substitute” for sheer power – just what this aircraft needed to achieve its full potential.

With the Super S-II modification, the aircraft now has 2,820lb thrust and it becomes more fuel-efficient. It will be able to cruise at 424kt.

Sierra Super S-II

Sierra says it can also reduce carbon emissions by as much as 27% while it cuts time-to-climb to FL430 to less than 25min. The modification claims to increase range to 2,300nm and increased maximum fuel payload. Sierra also says that there are “dramatic” reductions in take-off field length – more than 20% reduction at 5,000ft ISA +20.

The cost of the Super S-II modification is just shy of the $2m mark. The prototype made a follow-up 2h 55min flight on October 1 to validate initial impressions. The second flight “easily achieved 43,000ft crusing altitude and well over 400kt true airspeed with surprisingly low fuel consumption” Huffstutler says.  The aircraft landed with fuel tanks still more than half full.

Sierra holds an FAA Repair Station certificate and after nearly 30 years holds more than 75 proprietary Citation modifications.  The company holds over 300 FAA STCs.


Source: Flight Daily News