Sierra Industries is turning from base to final for approval of its Williams FJ44-engine modification program for the Cessna Citation 501SP, which it calls the FJ44 Eagle II. “We’ve been flying the aircraft very hard for the last three months and, barring any big problems, hope to be finished shortly after Thanksgiving,” said Chip King, Sierra program engineer. The solo Eagle II prototype had accumulated about 200 hr by the middle of last month and the company has been feeding test data to the FAA on a continuous basis. Earlier, said King, FAA officials had indicated they would not have time to do any flight testing and that Sierra should do it all. Now, however, he expects the FAA will want to do two to three days of flying to spot check Sierra’s data. Approval of the STC could come as early as the middle of this month, but this depends on the FAA. King said he expects Sierra will have the STC in hand by the end of the year.
When AIN spoke with King last month, Sierra’s airplane had just returned from high-altitude testing in Roswell, N.M., where coincidentally Cessna and Bombardier flight-test crews were doing similar tests with the CJ2 and CRJ-900, respectively. The last major test on the Eagle II’s docket is a retake of the engine fire-extinguishing system. The system passed the first test, but one of the 12 test sensors (located farthest from the extinguisher’s ejector) measured just slightly more than the 6 percent Halon/air concentration required. (Sensors near the front measured up to 80 percent concentrations.) Sierra engineers modified the ejector port and King expected the subsequent “Halonizer” test would show improved concentrations at the more remote sensors.
As soon as the STC is received, Sierra plans to ship two Eagle IIs, which are nearly completed, and soon after another pair, which are about 75 percent completed. The prototype Eagle II will also go eventually to a customer, but Sierra plans to hold it for a while to obtain operating data for the flight manual. The basic price of the Sierra FJ44 Eagle II retrofit is $1.55 million, less a to-be-determined trade-in discount for the Pratt & Whitney Canada JT15D-1A engines.