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Aviation History
2002
2002 - 1320.PDF
Prog ramme update delayed from early next year to mid-2005 as the engine undergoes a major redesign (see panel). Although the delay was a major blow, as most A318 customers had speci fied the P&W engine, Airbus has coped by reshuffling the programme, and PW6000 customers Frontier Airlines and Inter national Lease Finance have switched to the CFM56. Of the 108 A318s on order, around two-thirds are now CFMI powered. Flight-testing of the first aircraft at Air bus's centre in Toulouse is going well, says Engler, with 80h accrued to date. "The engine is performing very well. There have been no snags or isolated problems and the engine has been very reliable so far." The first phase of the certification pro gramme has been completed. It involved exploring and exceeding the normal flight envelope. The aircraft has been operated beyond its normal Mach 0.78 cruise speed to M0.87. Auto-land and auto-braking systems have also undergone initial tests. The first A318 is concentrating on tests of the engine/aircraft and nacelle integra tion for the PW6000, as well as the power- plant's new Papillion thrust reverser developed by Hurel-Hispano. The second aircraft, also fitted with PW6000s, will join the flight-test programme in June, when the prototype will be grounded for re- engining with CFM56s at Hamburg. This aircraft will resume flying in late August. "The 'identification' of the A318 [ie the defining of the control laws for the fly-by- wire control system] and aero-elasticity testing will be completed by June using the PW6000 version," says Engler. The third aircraft, the first production CFM56-powered version, is due to fly in May next year and will be used for a "very small" function and reliability test pro gramme. The CFM56 model is due for certification in May next year, with deliver ies commencing the following month to Frontier. This has been brought forward by three months to compensate for the delay. Meanwhile, the prototype A318 will be grounded again and returned to P&W power with the revised production stan dard PW6000. "This is due to take place by October 2004," says Engler. The entire flight-test programme will total l,050h, he adds, of which around 450h will be flown by the CFM56 version and the remain der by the PW6000 model. • T/»e Spirit of f/»e West 0 0 0 C 0 0 0 0 COO ENGINES GUY NORRIS / LOS ANGELES Pratt & Whitney strains every nerve to rescue PW6000 Pratt & Whitney will virtually restart the Airbus A318 PW6000 pro gramme, after setbacks have allowed CFM International (CFMI) to come from nowhere, overtake the incumbent, and assume pole- position. The result is a 30-month effort by P&W, based on the MTU- designed six-stage HDV12 high-pressure compressor (HPC), to resolve the performance snags that have dogged the engine from its initial tests. Although P&W appears to have had good warning that the once- rejected MTU design was the ready-made answer to boosting compressor flow and reducing fuel-burn, why has it fought so doggedly to use its home-grown five-stage design? Aside from value-per-engine factors, P&Ws focus on its simpler core reflected a determination to cut parts count and costs to a minimum. Arguments that the PW6000 would involve costs around one- third that of the CFM56 were convincing, and until Air France opted for the commonality of the existing engine, P&W enjoyed virtual exclusivity on the A318 from the moment of its launch. The subsequent problems, and its decision in early 2002 to delay entry-into-service by 30 months to mid-2005, have seen a gradual erosion of its market as Frontier Airlines followed International Lease Finance in switching to the CFM56. Added to the loss of TWA's A318 order following its take-over by American Airlines the previous year, P&W's stranglehold has disappeared. In view of the extensive changes to the PW6000 which will come with the likely selection of the MTU HPC (expected around 15 May) over an indigenous seven- stage HPC option, P&W says: "We are just not ready to talk about it". It adds, however, that, should the MTU decision be positive, the German company will negotiate for a risk-revenue shareholding of between 15 and 20%. MTU is a life-time preferred vendor to the PW6000 with its low pressure tur bine, but as Flight International went to press, not yet a full partner. CFMI is busy applying for joint European and US certification of two new CFM56-5B variants for the A318. Launch customer Frontier will receive its first A318 in July next year. The baseline -5B8/P is rated at 21,600lb (96kN) and the -5B9/P provisionally at 23,300lb. These engines will be derated versions of the A319/A320/A321 's -5B family, which is capable of higher thrust, and is rated at 32,000lb on the A321. So CFMI's savings are bun dled up in the dramatic derating of the A318 operation, and common ality benefits of interoperability, shared spares and maintenance. "We will use an identical bill of materials for the -5B in service on A318s, A319s, A320s and A321s," says CFM56-5 programme gen eral manager Ken Foley. Although not enjoying the installed weight benefit of the PW6000, "the commonality advan tage outweighs anything else," Foley adds. Early CFM56-powered A318 operators flying other A320 family members are expected to "mix and match" -5B engines to manage life cycle and mainte nance costs. The idea will be to remove higher-thrust rated engines from A321s, de-rate them and put them on A318s for another two years of service before removal. Conversely, new engines intended ultimately for A318s, will provide initial power on A321s before being swapped. The de-rated exhaust gas temperature margin of the -5B8/9 is so large, says Foley, that a life of 20,000 cycles on wing before major overhaul is expected. The dual annular combustor option is offered on the B9 but not on the B8, as emission certification tests were not conducted at this lower power level. xii 30 APRIL - 6 MAY 2002 FLIGHT INTERNATIONAL CENTRAL EUROPE SURVEY www.flightinternational.com
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