Early Learjets are set to benefit from a re-engining that will dramatically reduce noise and operating costs. Guthrie, Oklahoma-based Spiritwing Aviation has begun flight testing a Learjet 25D re-engined with Williams Rolls FJ44-2C turbofans, and plans to offer the conversion for all 20-series Learjets.

Replacing the original General Electric CJ610 turbojets is expected to cut fuel consumption by 60%. "We have to give up 1,300lb [590kg] of fuselage fuel, because certification rules won't allow fuel next to the engine, but we still increase range to 1,650nm [3,000km]," says director of operations Mike Penwell. This compares with around 2,000km for the original aircraft.

Spiritwing is hoping for supplemental type certification by the end of the third quarter, and is aiming for approval on all 20-series Learjets. The conversion is expected to cost around $1.7 million. Spiritwing is also developing a reduced vertical separation minimum upgrade for 20-series Learjets.

Source: Flight International