By 1990, as Boeing was studying the enlarged 767-X, Rolls-Royce was proposing its Trent engine with a larger fan driven by a new, bigger LP turbine, a modified IP compressor and no exhaust mixer. It would attain, to be certified in early 1995 for a mid-1995 introduction, with growth potential to with a new HP core. After being rebutted by British Airways, Rolls-Royce launched the Trent 800 in September 1991 with a £250 million order from Thai Airways to power 15 Boeing 777s, certification was then planned for 1995 and first deliveries for January 1996. Certification was applied for on 2 April 1992. By September 1992, its fan was to be tested in December and a full test was planned for September 1993. Certification was granted by the EASA on 27 January 1995. The Trent 800 entered service on the Boeing 777 in 1996, with Thai Airways on 31 March. In 1995, the Trent 800 won a large order from Singapore Airlines, a traditional Pratt & Whitney customer. In 1996, Rolls-Royce had a 32% market share, above GE but behind PW. By June 1998, the 33 aircraft fleet had a Trent 800 dispatch reliability over 99.96%. By July 1999, Rolls had won 45% of all engine orders for the 777. The Trent 800 later reached a 40% share of the engine market on the 777 variants for which it is available. The Singapore order was followed by large orders from American Airlines and Delta Air Lines. British Airways announced in September 1998 that it was returning to Rolls-Royce for its second batch of 777s, and did so again in April 2007. Other major operators include Air New Zealand or Kenya Airways. The last Trent 800-powered 777 was delivered in 2010. The later -300ER, -200LR, 777F, Boeing 777X-8 and -9 are powered exclusively by GE Aviation engines. As of 2014 Rolls-Royce is offering an upgraded version of the engine, known as the Trent 800EP. It incorporates technology from Trent 1000 and Trent XWB engines including elliptical leading edges on intermediate- and high-pressure compressor blades. Rolls-Royce claims that it provides a 0.7% fuel-burn benefit.
Design
The Trent 800 is an axial flow, high bypass turbofan with three coaxial shafts. The fan is driven by a 5-stage axial LP turbine, the 8-stage IP compressor and the 6-stage HP compressor are each powered by a single stage turbine. It has an annular combustor with 24 fuel nozzles and is controlled by an EEC. The engine has a 6.4:1 bypass ratio in cruise and an overall pressure ratio of 33.9 to 40.7:1 at sea level, for a 340.6-413.4 kN take-off thrust. The fan has 26 diffusion bonded, wide chordtitanium fan blades. Rolls-Royce claims it is the lightest Boeing 777 engine, citing a weight saving over the GE90 and over the PW4000. The Trent 800 weighs 6.078 t dry, while the GE90 is, and the PW4000 is. Japanese KHI and Marubeni Corporation are risk and revenue sharing partners on the Trent 800.
Operational history
On 17 January 2008, a British Airways Boeing 777-236ER, operating asBA038 from Beijing to London, crash-landed at Heathrow after both Trent 800 engines lost power during the aircraft's final approach. The subsequent investigation found that ice released from the fuel system had accumulated on the fuel-oil heat exchanger, leading to a restriction of fuel flow to the engines. This resulted in Airworthiness Directives mandating the replacement of the heat exchanger. Rolls-Royce developed a modification to prevent the problem recurring that involved replacing a face plate that had many small protruding tubes with one that is flat.
