Comac is using a dual supplier system to manufacture critical and potentially challenging parts of the C919 airframe, to ensure quality control and to prevent any major delays to the programme.
These include the aircraft's aft fuselage as well as its vertical and horizontal stabilisers, all of which are made of composites, Comac's chief engineer Jiang Liping tells Flightglobal in an interview in Shanghai.
She explains that Chinese suppliers are unfamiliar with the use of composites and that the airframer's concern is that the quality and strength of the parts produced by one supplier may not match the required standards.
An example is how the first aft fuselage delivered by Shenyang Aircraft Corporation had to be strengthened.
Comac also engaged two suppliers to build the C919's centre wingbox and mid fuselage due to anticipated complexities in the wing-to-body join of the aircraft.
"We do this so that we have a backup... the costs will go up but this is for quality control and also to ensure that the the programme's timeline is under control," says Jiang.
She adds, however, that Comac has stuck to the main suppliers thus far, since the manufactured parts have generally met standards.
Comac has largely completed the final assembly of the first flight test aircraft for the C919 programme, and is working towards a year-end roll-out followed by first flight in 2016.
Source: Cirium Dashboard
