Beijing - The Chinese aircraft manufacturer COMAC has suspended the flight tests of its single-aisle C919 for three months. The certification remains planned for 2020 the manufacturer says.

Commercial Aircraft Corporation of China (COMAC) announced the suspension of C919 tests for modifications, including flaps and empennage.

Changes are also made to the fuel tanks. Two of the three test aircraft have already been modified, and the third is being modified. Three more planes will be available next year for the certification campaign.

Flight tests will restart in July. In the meantime, the single-aisle underwent maximum-rate pressurization tests last week.

COMAC assures that the three months lost should not change the expected certification date of the C919 for the year 2020, with first deliveries the following year.

Recall that the C919 had made its maiden flight in May 2017. The aircraft is aimed to be a direct competitor to the A320 family and B737 series aircraft. It has accumulated 815 orders to date, mostly from Chinese leasing companies and airline operators.

In early June, The HNA group announced a framework agreement for 200 additional C919, but also 100 ARJ21, the regional jet produced by COMAC, which already entered service at Chengdu Airlines.