FJ44-powered Learjet Program Progressing Slowly

After some 100 flights, Spirit Wing Aviation of Guthrie, Okla., has completed development testing of its Williams FJ44-powered Learjet 25D and expected to begin about five months of FAA certification flying. The FJ44-2C turbofans replace the Learjet 25D’s original GE CJ610-8A turbojets. The prototype airplane first flew in January last year, at which time Calvin Burgess, Spirit Wing owner and president, expected the modification would be awarded its STC this summer. Certification is now expected in the fall. Burgess said the airplane has demonstrated the capability to achieve a range of more than 2,000 nm at 456 knots with NBAA IFR reserves. He hopes to keep the cost of the modification below $2 million. Some 163 Learjet 25Ds were built between 1976 and 1982, and about 145 are still flying. Published prices for the older Learjets range from $450,000 to $1.29 million.