What I-A needs for Alliance Air's regional operations is a rugged, reliableand economical workhorse. The B717 fits that bill admirably. Its range withfull passenger load of 1,500 nm is only half that of its competitors, but isadequate for Mumbai-Hanoi - well beyond what I-A requires. A competitor oncesaid that the B717 fits neatly between the antiquated B707 and B727. Notquite, says Rolf D Sellge, director, 717 product marketing.

"The B717 is about 18,000 lb lighter than the A318 with Pratt & Whitney(P&W) PW 6000 engines". On a flight of one hour to 1.5 hour, Sellge pointsout, the B717 takes about 18 minutes to climb to 30,000 feet and 20 to 30minutes for the descent. Coming to reliability, Sellge points out thatduring the 10-day proving flights over launch-customer AirTran's 33-citynetwork, the only mechanical delays was caused by a loose hydraulic pipe inthe wheel well. There was no delay or spares requirement on the recentflight to China and India.

The B717's BMW Rolls-Royce BR715 engines are the most modern and advanced oftheir type, with emphasis on maintainability, reliability and performanceretention. These are most vital under the punishing conditions of very shortflights and large numbers of cycles. The BR715 has a 10-stage high-pressure(HP) compressor - bigger than on the A318's PW6000 engine. While that makesit heavier, it also reduces compressor loading per stage.

P&W claim that the PW6000 has four compressor and turbine stages less, andthat the airfoils make up 60 per cent of the parts cost in maintaining anengine. In any case, the BR715's overall pressure ratio of 33:1 is quitegood for that segment, and offers high efficiency. Also, the BR715's turbineentry temperature is very conservative at 1,050 to 1,100 degrees K.

Additionally, the very heat-resistant turbine blades have the latest coolingtechnology to keep metal temperatures low. All that minimises wear and tear.The BR715 engine offers a very low cabin as well as airfield noise. The B717is claimed to have "The quietest interior sin its class." All types ofairfield noise are well below Federal Aviation Administration Stage IIIlimits, with approach noise being eight decibels lower. Similarly engineemissions - oxides of nitrogen, smoke, carbon monoxide and unburnthydrocarbons - are all well below current International Civil AviationOrganisation (ICAO) limits. The BR715 is a gem of an engine, and shouldfind wide application.

Not having advanced technologies like fly-by-wire controls and advancedstructural composites helps to keep the B717's list price down. It is about$31 million for the B717, $36 million for the A318, but only $27 to $29million for the Avro RJ100. While this amounts to comparing apples andoranges, the B717 does have a very competitive list price. After duebargaining, the B717 could be had for something over $25 million.

Sellge expects the overall 100-seat aircraft market to be 2,600 units over20 years, of which the B717 hopes to win 1,000 orders. Currently ordersstand at 115 firm and 110 options. Soon to be added is a Hawaiian Airlinesorder - 13 firm and seven on option. Sellge adds that a leasing company isabout to place 15 firm orders and take 15 options. That will take the totalto 143 firm orders and 132 options. The B717 should appeal to operators ofthe 651 DC-9s, 916 B737-200s and 428 Fokker jets still in service globally.It may also be right for operators of large turboprop aircraft graduating totheir first jets. Some major carriers can also order the B717 for theirregional subsidiaries. Future stretched and shortened versions could furtherwiden the market.

Of all the advantages of the A318, including greater speed and range, amajor one is commonality with the A320 family, though not in engines. Pilotsof one aircraft will be able to fly the other, for more efficient crewutilisation. I-A now have a rare, never-to-be-repeated chance to eliminateone aircraft type from their fleet, and thus to effectively standardise on asingle aircraft type. The biggest question for I-A will be how farcommonality is offset by greater simplicity, maintainability and otherfactors indispensable to effective multi-sector shorthaul operations.