An AirAsia jet with 162 people on board disappeared Sunday while flying from western Indonesia to Singapore on a scheduled two-hour flight. Here’s a look at the key developments.

Air Asia Flight 8501 takes off from Surabaya, Indonesia’s second-largest city, at 5:31 a.m. Sunday (2231 GMT Saturday), bound for Singapore.

The last communication between the pilot and air traffic control is made at 6:13 a.m. (2313 GMT Saturday), when the pilot asks to turn left and climb to 34,000 feet (10,360 meters) to “avoid clouds,” according to Djoko Murjatmodjo, Indonesia’s acting director general of transportation, who also said there was no distress signal from the cockpit.

AirAsia says the Airbus A320-200 was on the submitted flight plan route. Murjatmodjo says it is believed to have gone missing somewhere over the Java Sea between Tanjung Pandan on Belitung island and Pontianak, on Indonesia’s part of Borneo island.

A search and rescue operation is launched involving Indonesia, Singapore and Malaysia. Three Indonesian aircraft are dispatched to the area, while Singapore’s air force and navy search with two C-130 planes. The air search is suspended at nightfall, and is set to resume at 6 a.m. Monday.

Dozens of relatives of people aboard the plane gather in a room at Surabaya airport to await word about their loved ones. Among the passengers were three South Koreans and one each from Singapore, Malaysia and the United Kingdom. The rest were Indonesians.

Malaysian businessman Tony Fernandes, AirAsia’s chief and the face of the company, tweets, “This is my worst nightmare.” He also tweets that he is heading to Surabaya.

Photo Credit: Passengers queue for their flights at the AirAsia check-in counter in Changi International Airport on Sunday, Dec. 28, 2014 in Singapore. An AirAsia plane went missing on Sunday while flying over the Java Sea after taking off from a provincial city in Indonesia for Singapore. Wong Maye-E / Associated Press