Turbine-engine technology development is going in two directions. One is the development of new technology to push the envelope of performance, operational safety, maintainability and reliability. The other is to refine and update existing engines for long-term use, especially in light of more stringent Stage 4 requirements and existing Stage 3 rules.
The PW600 family of small turbofans, in the form of a 2,500-lb-thrust demonstrator engine, entered flight test last month mounted on P&WC’s Boeing 720 testbed. The engine was tested to an altitude of 43,000 ft and performance, handling and relight testing “exceeded our expectations,” said P&WC director of small turbofans Maurice Weinberg. The engine has not yet been selected for any specific airframe.
Early next year Boeing will offer a kit for BBJs and BBJ2s that will provide a 6,500-ft cabin at FL 410 instead of the standard 8,000-ft cabin. The kit, which can be installed on green and in-service BBJs, is expected to cost less than $100,000. Components include new cabin-pressure-controller boxes with revised software, a new cabin-altitude indicator and two pressure-relief valves.
Two NASA-industry partnerships could produce tangible benefits for aircraft operators in the near term. The turbofan engine research is being conducted by NASA Glenn Research Center in Cleveland as part of its aerospace propulsion and power program, the same division that Williams International teamed up with to develop the 700-lb-thrust FJX2 turbofan.
Turbine engine overhauler Red River Turbines has built the world’s first commercial T-9 military spec depot-level engine test cell.
Pratt & Whitney Canada last month announced its plan to invest $90 million in the construction of a new flight-test operations center at Montreal Mirabel International Airport. The 164,000-sq-ft facility will feature two bays and will support a range of engines, from turboprops to turbofans producing up to 90,000 pounds of thrust.
Starting with its first “clean sheet” engine design since 1972, but minus one of the two original customers, Honeywell brought the new AS907 to dual FAA engine and production certification in June, just 44 months after the project was launched.
Cessna 650 Citation III, Madison, Wis., Oct. 9, 2005–The inadequate design of the engine’s interstage transition duct yielded after the low pressure turbine (LPT) stage-3 blades had separated and allowed the uncontained release of turbine debris, according to the NTSB. A contributing factor was the separation of a turbine blade.
Reports of six uncontained turbine-wheel separations attributed to fatigue damage have prompted a proposed AD to require replacing certain turbine stator assemblies on Honeywell TPE331 turboprops. The directive would affect 2,350 engines installed on U.S.-registered aircraft at an estimated cost of approximately $8,200 per engine.
Hawker Beechcraft Beechjet 400A, Norfolk, Va., June 14, 2006–The NTSB said the probable cause of the dual engine flameout was the accretion of high-altitude ice crystals on the compressor vanes and their ingestion into the engine high-pressure compressor when the pilots pulled back the power levers. This caused compressor surges and the flameouts of both engines.