Deliveries of the carrier's 19 new Boeing 777-300ERs commenced in mid-2011, with the aircraft forming the new "backbone of its future longhaul operations. " The new Boeing 777-300ERs replaced the Boeing 747-400s on routes to U. S. destinations such as Los Angeles, New York, and San Francisco, but was expected to first enter service on flights to Paris from March 2012. The Boeing 777-300ER began to replace most 747 service once sufficient numbers entered the fleet. Air China expanded its operations in India with a Beijing-Mumbai route begun in September 2011, while the existing Delhi route was upgraded to the A330. The airline also launched service to Mumbai from Chengdu on 2 May 2012. The airline began using the Boeing 777-300ER on one of its two daily Beijing-Los Angeles flights on 1 February 2012. Beginning in late-2012 to early 2013, the airline will replace the Boeing 747-400s currently servicing the New York and San Francisco routes with the Boeing 777-300ER. With the addition of the Boeing 777-300ERs on the US routes, Air China increased frequency on the Beijing-New York route, changing the flights from 7 to 11 flights a week by adding two new flights to the route (CA989/990). On 21 January 2014, the airline launched its service to Hawaii with flights from Beijing to Honolulu, the first nonstop flights between the two cities. The airline also increased the frequency of service on the Beijing-Houston Intercontinental route from four times weekly to daily service from 30 March 2014. Beginning 10 June 2014, Air China introduced new nonstop service from Beijing to Washington-Dulles, operated by a Boeing 777-300ER. As of September 29 2015, Air China also introduced a 3 times weekly flight to Montréal–Pierre Elliott Trudeau International Airport in a codeshare with Air Canada. The Montreal flight was extended to Havana from 27 December 2015.