Chinese airframer Comac is cutting down on the use of composites for its C919 narrowbody programme.
The airframer had initially planned for composites usage on the C919 to amount to around 20%, but that figure could now drop to less than 10%, sources familiar with the project tell Flightglobal Pro.
The reduction in composite usage is intended to avoid complications and possible delays, which the five-year-old airframer may not be experienced enough to handle, sources add.
Comac has yet to ascertain the material mix it will use for its 150-seat jet, and has "two workflow lines". One line will work on a more traditional design with the aluminum-lithium alloy, while the other on the wider use of composites. If composites prove too challenging, the company can quickly shift to a more traditional approach.
The low use of composites however means that the C919 will - from a structural perspective - be a little more advanced than the current generation of Airbus A320 and Boeing 737 aircraft, against which it was intended to compete with.
In January, Comac said that the C919 central wing structure had passed a critical design review. The design of its composite structure was also evaluated and allowed to proceed to the next phase.
This year, the C919 is due to complete detailed design and start on comprehensive manufacturing.
To speed up the development and test process, the airframer will have two iron birds to mount equipment for static tests. The first iron bird ground rig had already been set up when Flightglobal Pro visited Comac's facilities in Shanghai recently, although no equipment had been installed.
To avoid delays in certification similar to those suffered by the ARJ21, a project started over 11 years ago, Comac is also working more closely with the Civil Aviation Administration of China (CAAC) earlier on in the process.
Last August, Comac signed a project specific certification plan that details procedures and schedules to ensure that work is carried out efficiently between the airframer and the CAAC to expedite the certification of the aircraft.
Suppliers say they are looking forward to a smoother transition into certification work and entry into service for the C919, as Comac puts lessons learnt from its regional jet programme to use.
They add that Comac needs to get its ARJ21 certificated soon, so that it can focus its limited resources on the C919. This is because there is a limited pool of design, development and engineering capability in the country, and many of those involved in the ARJ21 are also a part of the C919 team.
The C919 is scheduled to have its first flight in 2014, with deliveries to begin in 2016. Comac has so far received commitments for 380 of the aircraft, mostly from Chinese airlines and leasing companies.