The Pratt and Whitney PW4000 Turbofan Engine       

The Pratt and Whitney PW4000 engine family spans from 50,000lbs to a planned 100,000lbs thrust and comes from the Pratt and Whitney division of United Technologies and is assembled in Hartford, Connecticut. Although the PW4000 series of turbofans predates the 777 and first served in 56,000lb guise on the Boeing 747-400 and later on the Airbus A330, the PW4084 84,000lb variant was designed specifically for the 777. Perhaps the least innovative of the three engine offerings, the PW4000 engine core has a proven history and was chosen by launch customer United Airlines. Since then, the PW4000 has captured more orders than any of its competitors. One of Pratt and Whitney's key advantages in the PW4000 is its siginificant parts commonality with other PW4000 cored engines powering aircraft such as the Boeing 767, 747-400, as well as the McDonnell Douglas MD-11 and the Airbus Industrie A330. For many operators, this commonalty was a deciding factor whose resulting savings in service and parts inventory costs more than offset the lower thrust growth potential and higher specific fuel consumption from this older core design. With these commonality factors, its lower initial purchase cost, and lower maintenance costs, the PW4000 line provides the lowest cost of ownership to many, but not all, airlines. The PW4084, certified at 84,000lbs, features a 112inch fan with powder metal disks and single crystal turbine blades. Pratt and Whitney also claims its Floatwall (TM) combustor produces the lowest emissions of any 777 engine. Growth versions of the 112inch fan on a PW4000 core are planned for 90,000 and 98,000 lbs for growth version of the 777 such as the -300 and -200IGW. The PW4084 was used on the first 777 flights and was the first engine ever certified for 180 minutes ETOPS on the date of delivery. Customers include launch customer United Airlines, as well as all three Japanese operators, All Nippon Airways, Japan Air System, and Japan Air Lines. These three airlines share a common B-777 / PW4000 maintenance base thus further reducing their costs.