Citation IIs Sierra Style
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Sierra Industries' modifications of the Cessna Citation II and S-II offer dramatic improvements in range, cruise speed, fuel efficiency and climb performance. When coupled with paint, interior and avionics updates, the total cost of a package is typically about half of what a comparable new business jet would be.
The fuel efficiency is another benefit both in terms of cost and utility. Both Sierra airplanes have substantially better range than the originals, thanks to higher cruise speeds and more efficient engine design. According to Sierra's numbers, the Super II has an NBAA range of 1,775 nm, a 397 nm improvement over the Citation II, and its 400 knot max normal cruise speed is 45 knots faster than the unmodified airplane. The Super S-II has an NBAA range of 2,300 nm, which is 461 nm better than the S-II, and its 420-knot typical cruise speed is 35 knots faster than the already fast Citation II's 385-knot figure. With the Sierra mods, max fuel payload is especially noteworthy in the Super II, which has 1,278 pounds of payload compared with just 328 for the Pratt-equipped Citation II. The Super S-II improves on the S-II's 1,036-pound max fuel payload by better than 400 pounds.
The speed and range improvements are striking, but the climb performance upgrade is arguably the most noteworthy benefit that owners will see. As part of the STC, the ceiling on both IIs increases from FL 410 to FL 430, and while both previous airplanes needed to step climb to their maximum altitude, a process that would take well over an hour or substantially longer depending on temperatures, the Super II and Super S-II can get up to 430 with no intermediate stops in right around 25 at max takeoff weight. As you might guess, this is one of the main drivers of the improved range figures, as the airplanes get up to more fuel efficient altitudes much faster, saving fuel and increasing trip speed.
Flying the Super II: An Eye Opener
A short while back Mark Huffstutler and Gary Buchanan from Sierra flew up to Austin in a Super II to pick me up and fly me down to Uvalde so I could see firsthand just what Sierra does and how they do it.
What they mainly do, of course, is make good airplanes better, and my experience in the airplane was an eye-opening introduction to that fact.
For the first flight, Mark was at the controls, and he, like demo pilots the world around, wanted to show me what his airplane could do. We were fairly light, with 2,100 pounds of fuel and roughly 600 pounds of people aboard, for a takeoff weight of 10,374 pounds.
After getting cleared to take off, Mark lined it up and advanced the throttles while holding the brakes. The Super II is a single-pilot airplane, and the addition of fadec makes it without question a better and safer single-pilot airplane. When Huffstutler released the brakes, we rocketed forward. It was quite a spectacular display, and as we departed and climbed out he had to raise the nose to an extremely high deck angle, in order to keep the airspeed at the desired 200 knots. It seemed as though it took no more than 30 seconds to reach our preliminary clearance altitude of 4,000 feet, and Huffstutler had to push the nose hard over to level off. It's not how one would normally fly the airplane, but it made the point. There is performance to spare. We were, in fact, seeing a rate of climb of around 5,000 fpm. Single-engine climb is better than 1,700 fpm at max takeoff weight.
As usual, we didn't get a direct climb to FL 430, but factoring out the brief level-offs it took us less than 18 minutes to get to our ceiling. And at FL 430 we were seeing a true airspeed of 390 knots on 775 pounds of fuel per hour. In all, the trip down to Uvalde -- we made a lengthy detour so I could see the airplane do its thing -- covered 279 nm, took one hour and seven minutes to fly, and we burned 900 pounds of fuel in the process. The flight culminated in an RNAV approach to near minimums at Uvalde.
Based on our flight compared with the POH figures for the original, Pratt-powered airplane, the Super II is 44 knots faster at the same fuel burn under the same conditions. When you pull the power back to the same cruise speed as the Pratts, the fuel burn is around 25 percent lower with the FJ44s.
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Among the many Sierra STCs for the Citation lineup is enlarging the door. The mod is popular with air ambulance companies and cargo haulers.
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Touring Sierra
Normally, I'd call what I did when in Uvalde a "factory tour," but I had to remind myself that Sierra doesn't really build new airplanes, even though it does seem like it at times.
The municipal airport at Uvalde has a single, 5,000-foot-long runway with hangars huddled around it. Many of those hangars belong to Sierra Industries. As of my visit, the company had 85 full-time employees and 84,000 square feet of hangar space, where workers perform every imaginable kind of maintenance work on airplanes, mostly Citations but not exclusively.
On my visit I got the chance to see not only the scope of what Sierra does -- it's quite an operation -- but how it goes about it.
I saw a number of Citations in various states of modification, some just getting started on the project and some nearly ready to fly. On one airplane Sierra technicians had just gotten finished installing the engine support for the new FJ44s, and the structure itself was telling. Instead of removing and beefing up the existing supports, Sierra adds an extra member running through the fuselage side to side, supporting each engine, adding strength without compromising the existing underlying support structure. It's a smart and robust solution.
As a part of its core work, Sierra has to create new parts, and to this end it has invested in that capability, with state of the art machine and sheet metal shops, as well as a separate fabrication shop.
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