Chinese leasing company ICBC Leasing has inked an order for 45 Comac C919 narrowbodies and agreed to become the launch customer for the aircraft.
This is the largest order for the aircraft, which is being developed in China as a possible competitor to the Airbus A320 and Boeing 737 family of aircraft.
Neither ICBC Leasing nor Comac revealed the financial details of the order.
"As launch customer, ICBC Leasing will actively participate in projects related to C919 research and development, and aircraft design," said Comac in a statement.
Jiang Jianqing, chairman of ICBC Leasing's parent company, the Industrial and Commercial Bank of China, said that his company's order reflected its support of the development of China's aviation industry.
"This signing is bound to promote the smooth implementation of China's large aircraft project, the national aviation industry, the development of the leasing industry which has a very important role," he added.
It gives Comac 145 firm orders for the aircraft, almost all from Chinese airlines and leasing companies.
The C919 is scheduled to make its first flight in 2014 and receive its certification in 2016, but that is widely expected by industry sources to be delayed.
CFM International's Leap-X1C will be the sole powerplant to launch the C919. Several other western suppliers have also come on board as suppliers of various key components of the aircraft.