HONG KONG, Dec 22 (Reuters) - Air China plans to raise up to 6.0 billion yuan ($842 million) in a private share sale on the Shanghai Stock Exchange to expand its fleet and replenish working capital, it said on Friday.

The flagship carrier is aiming to sell up to 854.7 million shares, equivalent to 30% of its existing capital, to its controlling shareholder China National Aviation Holding Corporation Limited, it said in a statement to the Shanghai exchange.

Air China will use 4.2 billion yuan of the proceeds to fund the purchase of 17 airplanes, with the remaining 1.8 billion yuan used to boost its working capital, according to the filing.

The Chinese airline did not disclose the details of the aircraft acquisition plan.

At the end of November, the group operated a fleet of 900 aircraft, including 386 company-owned aircraft, 215 under financial leases and 299 under operating leases.

Separately, Air China also said it planned to raise up to HK$2.0 billion ($256 million) via a private placement of H-shares to replenish capital.

($1 = 7.1248 Chinese yuan renminbi)

($1 = 7.8135 Hong Kong dollars) (Reporting by Twinnie Siu in Hong Kong and Ella Cao in Beijing Editing by Mark Potter)