The engine that launched the 747-400

The Pratt & Whitney PW4000-94, named for its 94-inch fan, was one of three engine families offered on the 747-400 - and the one that launched the type.

Key facts
Applications	747-400 (PW4056) and 747-400ER (PW4062A) - only 747 variants
Thrust classes	PW4056 56,750 lbf; PW4062A 62,000 - 63,300 lbf (rating standard dependent)
Bypass / fan	4.8 - 5.0:1; 94 in fan ("PW4000-94" family)
Launch customer	Northwest Airlines - ordered December 1985; first aircraft January 1989; first revenue flight 9 February 1989

The PW4000 programme was launched in December 1982 and the engine was FAA-certified in July 1986, first flying on the Airbus A310. Northwest became the launch customer for the PW4000-powered 747-400, and its first aircraft N663US entered revenue service on 9 February 1989, launching the 747-400 programme itself.

The 747-400 was the first type certified with three different engine families in a single flight-test programme - PW4000, CF6-80C2 and RB211-524G/H - receiving FAA certification on 10 January 1989. The 747-400 prototype N401PW (later N661US) served as the PW4056 testbed.

The PW4062A, a higher-thrust derivative with a higher overall pressure ratio, was created for the 747-400ER's 412,000 lb-weight, longer-range mission. Beyond Northwest, PW4000 customers on the 747-400 included United, Singapore Airlines, Korean Air, and many Asian carriers.

The engine that launched the -400

The PW4000-94 - named for its 94-inch fan - is the engine most associated with the 747-400 because it launched the type. Northwest Airlines ordered the PW4000-powered 747-400 in December 1985, the first aircraft entered service on 9 February 1989, and it flew the type's revenue launch flight. The 747-400 prototype itself, N401PW, served as the PW4056 testbed.

Three engines, one programme

The PW4000's place in 747 history is as much about competition as thrust. The 747-400 was the first airliner type certified with three different engine families - PW4000, CF6-80C2 and RB211-524 - in a single flight-test programme, receiving FAA certification on 10 January 1989. That competition gave airlines a genuine choice on the -400, in contrast to the 747-100's single-engine lock, and it is the era covered on the engines overview page.

The -400ER's engine

The higher-thrust PW4062A, with a higher overall pressure ratio, was developed for the 747-400ER's long-range, heavy mission, and it powered most -400ER freighters. The distinction between the PW4056 and the PW4062A is a good illustration of the thrust-rating trade-offs that ran through the whole 747 family: the higher rating bought range and payload at the cost of engine life and hot-and-high margin. Beyond Northwest, PW4000 747-400 customers included United, Singapore Airlines and Korean Air.

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