Engine commonality may help aftersales

The engine that will power the ARJ21-700 is the same type powering the Embraer 190, another 90-seat regional jet that will operate in China - and could help when it comes to establishing after-sales product support.

There will be an engine maintenance, repair and overhaul facility in China for the ARJ21-700 is General Electric CF34-10A engine and GE has previously said it may select a completely new provider or appoint an existing MRO in China to do the work.

It has also said the MRO that handles ARJ21-700 engines could also be handling the CF34-10E, which powers Embraer 190s. No E-190s now fly in China, but Hainan Airlines has 50 on firm order.

Chuck Nugent, GE Aviation general manager small commercial engines, declines to say which engine MRO will be chosen, citing the fact that the first ARJ21-700 is only due to enter service in late 2009 so it is several years away before any engines will need to be overhauled.

But having an engine MRO in China for CF34-10A engines is crucial because it means ARJ21 operators will avoid the costs involved in shipping engines overseas for repair.

GE is also looking to generate cost savings by having CF34-10A engines assembled in China, but Nugent says that initially all the engines will be assembled at GE's plant in Durham, North Carolina.

Some of the engine's components are already being made in China, "and we have a clear strategy to source more components in China", Nugent says, but he declines to say which engine maker will be chosen.

Final assembly of the first ARJ21-700 airframe is under way in Shanghai and Nugent says GE will deliver the first two engines at the end of this year. ACAC is due to roll out the first aircraft towards the end of the year.

Because the CF34-10A is similar to the -10E there has been no need for GE to conduct flight tests for the CF engine, says Nugent. Instead, the -10A's first flight will take place next year when the ARJ21-700 has its first flight. Nugent says GE plans to have "four engines plus flight-test engines as part of the test programme".

But he says the CF34 is proven technology and "the CF34-10E will have had 1 million flight hours before the -10A goes into service".

Nugent says ACAC's thrust requirements for the ARJ21-700 "have pretty much stayed the same". This is despite the fact that ACAC encountered some issues with the aircraft's overall weight.

The CF34-10A has a nine-stage compressor and delivers 17,500lb of thrust (78kN), says Nugent, adding that "there is clearly potential to increase the thrust and we can go up to 20,000lb". This is important for the ARJ21-900, the stretched version that ACAC plans to build later.

Nugent says about 80% of the CF34-10A is common to the CF34-10E, but there are some key differences because the ARJ21 engines are rear-fuselage mounted whereas the E-190's engines are mounted under the wing - the gearbox has been relocated, for example.

To ensure that this high-cycle engine is cost-efficient to maintain, GE has gone for "modular architecture and a simple single-stage turbine", says Nugent.

He adds that the engine has a "wide-chord fan blade, fewer fan blades and more thrust".

Source: Flight International