BEIJING, March 1 (Reuters) - China Eastern Airlines , the launch customer for China's home-built C919 jets, signed a firm order with the state planemaker on Monday to buy five of the narrowbody aircraft, the Commercial Aircraft Corporation of China (COMAC) said.

The carrier, which signed a letter of intent with COMAC in 2010, is expected to take delivery of the first C919 aircraft this year once they are certified by China's aviation regulator.

The C919, which will compete with Boeing Co's 737 and the Airbus SE A320, is widely regarded as a symbol of China's civil aerospace ambition.

Without disclosing a value for the deal, COMAC said in a statement on social media that the aircraft would be based in China Eastern's headquarters in Shanghai and be deployed in routes to Beijing, Guangzhou, Shenzhen, Wuhan and others.

COMAC's C919 plane has received 815 provisional orders, but very few from airlines or leasing firms outside China.

(Reporting by Stella Qiu in Beijing and Jamie Freed in Sydney; Editing by Edmund Blair)