Comac is on a mission to optimise and upgrade its ARJ21, following feedback from launch customer Chengdu Airlines.
The carrier took delivery of its first ARJ21 last November, and started deploying the aircraft between Chengdu – its home base – and Shanghai in June. Speaking to FlightGlobal in Shanghai, programme vice-chief designer Zhao Keliang says Comac is working through a list of improvements for the jet. These include reducing cabin noise, simplifying the aircraft’s alert and warning systems, installing a satellite communications system, resolving door pressure issues and making it safe for operations even in heavy rain.
Zhao says Comac will add a layer of soundproofing material to reduce cabin noise, which is especially loud towards the rear of the aircraft near its GE Aviation CF34-10A engines. He expects installation of satellite communications equipment and simplifying of the warning system to be relatively straightforward.
Sources say the last two rows on Chengdu Airlines’ ARJ21 are left empty due to the loud engine noise, and that the aircraft operates only in fine weather.
Zhao explains that the aircraft is allowed to operate in moderate rain and only where water on the runway does not exceed 3mm deep. This is because the Chinese manufacturer was unsuccessful in several water indigestion tests during the certification process, with water splashing into the engines, affecting thrust.
Comac is working through these issues, and Zhao says the changes should be completed by the end of 2017, allowing Chengdu Airlines to operate the aircraft smoothly and without any restrictions.
The more challenging task, however, lies in upgrading the aircraft’s systems and functions, as well as reducing weight and drag.
The ARJ21 is currently “a few hundred kilograms overweight”, Comac says. The rookie airframer’s more conservative approach meant it specified greater strength for its structures, adding weight to the aircraft. The company is now looking at using lightweight composite seats, and also refining its design to allow for overall weight reductions. An improved ARJ21 should be ready by 2019.
FlightGlobal understands that the Civil Aviation Administration of China has also given Comac a list of seven or eight improvements it must make to the jet before it will provide a production certificate for the type.
Officially, the manufacturer hopes to achieve a production certificate by the end of 2016. Until then, each aircraft has to be certificated individually before it can be delivered.
The second ARJ21 is also ready for Chengdu Airlines, which has a further 28 on order. Comac is aiming to deliver three to four of the regional jets next year.
“Right now, it’s like we just graduated from primary school,” says Zhao. “Even with entry into service, we still need to continually improve the aircraft and mature it.”
Source: Flight International
