If two competing companies have their way, Cessna 550 owners will soon be able to take their jet farther and higher, all while paying less per mile to do it. Cessna Citation modifier Sierra Industries of Uvalde, Texas, and industry newcomer Clifford Development of Toledo, Ohio, are simultaneously developing modification kits that they hope will bring Williams International FJ44-3 engines with dual-channel fadec to the Citation II within the next seven months.

According to Sierra Industries owner and president Mark Huff-stutler, about 900 Citations qualify for the modification.

New 3,000-pounds-thrust Williams FJ44-3 engines for the Citation II (550) spell major performance improvements for owners. Sierra expects that by replacing the jet’s original 2,500-pounds-thrust Pratt & Whitney Canada JT15D-4 and -4B engines, it can give the conversion, which it calls the Super II, a 420-knot maximum cruise (up from 376 knots); 365-knot long-range cruise (up from 307 knots); two-engine climb of 4,500 fpm (versus 3,070); 1,775-nm NBAA IFR range (versus 1,378 nm) with three passengers, one pilot and 45-minute reserves; and payload with maximum fuel of 1,629 pounds (versus 629 pounds).

Clifford is touting similar numbers, although it thinks 370 knots is possible in long-range cruise. The company also said that time to climb to 43,000 feet, which is virtually impossible with an unmodified Citation II, will be reduced 80 percent, to 20 minutes. Perhaps most impressive, however, is that Clifford is touting a 20-percent reduction in fuel cost per seat mile, from 46 cents to 37 cents. Overall, the new engines promise to improve reliability as well, according to Huffstutler.

Sierra, which usually brokers airplanes it has converted, said a typical low-time airframe will sell for about $3.45 million. Given that a standard unmodified Citation II can be had for anywhere between $1.5 million and $2.5 million, depending on the year, the Sierra conversion will likely end up being less expensive than Clifford’s. Though Clifford has yet to price its conversion, the current thinking is that it will sell for around $2 million, a representative said.

Where Clifford feels it has the edge, though, is its business approach. Clifford CEO James Clifford said his company will bring its product to market in a different way from Sierra, which has had success with its Citation I mod.

In essence, the company will develop the STC and then license various service centers around the country to install and service the product, almost like an OEM. This allows the company to sell as many kits as is necessary to meet demand, while continuing to develop new products, which will definitely happen in the future, Clifford said. “How many airplanes can I do in a year? How many customers want it?”

With Clifford’s approach, his company and the service center receive a portion of the sale. He added, “My modification brings a lot of secondary work.” Sierra has already proved this is the case, as the company is offering other options during customer modification such as paint, interior, avionics and digital engine instrumentation upgrades.

Both companies expect to fly the mod this month, and both expect the modification to be certified in the third quarter, with Clifford ready to take orders at the NBAA Convention in September.

Both companies have high hopes for the future. Clifford confirmed it will be aggressively pursuing other opportunities. As a forecast of what might be to come, a company spokesman told AIN, “You look across three different airframes and you engineer once with all three airframes in mind.” Sierra also expects to expand its success to the Citation S-II almost concurrently with the standard II. In fact, the modification should be certified in January, the company said.