Mitsubishi Aircraft aims to complete the design of its MRJ regional jet by the end of August and is working on a plan to develop an after-sales support network.

Company president Hideo Egawa says "we are working on the final details so we can freeze the design". This is expected by the end of August.

Mitsubishi has completed the preliminary design review and is working on the joint definition phase, he adds. The company in September made major changes to the aircraft's design, in response to airline feedback. It was originally planning to adopt carbonfibre for the wings, but switched to aluminium alloy.

Egawa says the wings on smaller aircraft such as the MRJ have more curvature than on a large airliner like the Boeing 787, which has composite wings. As a consequence, the smaller wings require more structural support inside the wing, he adds.

He adds that wings need manholes to allow access for maintenance engineers, and that all manholes must be reinforced. The problem with the MRJ is that the manholes are significant in size in proportion to the wing.

Trans States MRJ

These weight-gaining factors mean there is no great benefit in having composite wings for the MRJ, adds Egawa.

Another factor behind the decision is that Mitsubishi is considering a 100-seat stretched version of the MRJ, says Egawa. It is easier to adjust the size of the wing during the manufacturing process if the wing is made from metal, he adds.

Despite the switch to aluminium alloy for the wings, Mitsubishi still plans to use carbonfibre for the empennage, using the vacuum-assisted resin transfer moulding production process, says Egawa.

One advantage of this technique is that Mitsubishi can bake the empennage - to harden it - using a non-pressurised oven. Composite parts manufactured using other techniques often need to go into a pressurised autoclave oven, an expensive piece of equipment.

The MRJ is due to fly in 2012 and first delivery is scheduled for 2014 to launch customer All Nippon Airways. It has also added US airline Trans States Holdings to its customer list.

In an effort to win more customers, Mitsubishi is working to create a customer support network. This involves signing maintenance, repair and overhaul firms as approved MRJ facilities.

Mitsubishi will also work to ensure there are spare parts warehouses in key locations around the world, so customers have ready access to spares. A support centre will also be available offering customers 24h technical assistance, adds Egawa.

Source: Flight International