Comac appears to be on the verge of finally getting its much delayed ARJ21 regional jet certificated, after having completed all the necessary ground tests and 95% of all flight test modules.

Its four flight test aircraft have so far completed 2,652 flights, accumulating 4,812 flight hours.

The programme’s vice-chief designer Zhao Keliang tells Flightglobal there are about 10 flight test certification modules left to be done. These include tests on the aircraft’s maximum break energy, rejected takeoff and its flight control system.

The ARJ21 also needs to undergo functional and reliability testing, which would require the aircraft to fly for another 150 hours. This means that the test fleet would surpass the 5,000 flight hour mark by the time it is certificated by the Civil Aviation Administration of China.

Zhao admits frankly that Comac’s inexperience in aircraft development, supply chain management and certification has led to the long delay in the programme, which started in 2002.

“The aircraft flies, issues are detected, and then changes have to be made. This is a very time consuming process. This speaks of our inexperience.”



He adds that changes often have to be made to various aircraft systems – from avionics to landing gear - after test data is crunched, and suppliers could take months to make the modifications.

Issues with the aircraft’s emergency landing gear system, for example, took four years to resolve. The airframer also passed the natural icing test only on its fifth attempt, because the necessary weather conditions could not be met in China.

Comac has so far secured commitments for 258 ARJ21 regional jets, mostly from Chinese airlines and leasing companies.

The airframer is aware that the ARJ21 would be dated by the time it enters service, especially when facing pressures from newer types such as the Mitsubishi MRJ regional jet and Embraer’s E2 family of re-winged and re-engined jets. Early discussions on an improved version of the regional jet has thus been started to ensure that the aircraft stays competitive.

Full-swing discussions will commence once CAAC certification is obtained, says Zhao. Comac wants to reduce the aircraft’s structural weight, improve its avionics and power systems, and also enhance the manufacturing of its exterior to produce a smoother surface to reduce drag.

There are, however, no near term plans to re-engine the ARJ21, partially because of an agreement that makes GE Aviation the sole supplier of the type’s engines. The ARJ21 is powered by GE’s CF34-10A engines.

Zhao expects Comac to produce 30 to 40 of the current ARJ21s, before the improved variant is rolled out.

Already, the airframer is building a second assembly line for the ARJ21 at its in-construction final assembly centre near Shanghai’s Pudong International airport. The new facility will have a more efficient straight flow line, unlike the current system at Shanghai Aircraft Manufacturing Co where the aircraft has to be towed to four different stations.

When construction is complete, the two lines will have a combined capacity to produce 50 ARJ21s annually.

Publicly, Comac says securing US Federal Aviation Administration's certification of its regional jet is still an objective, but it appears it is no longer a priority.

Source: Cirium Dashboard