Indonesia called off until first light a search for an AirAsia plane carrying 162 people from Indonesia's Surabaya to Singapore, which went missing on Sunday just after pilots requested a change in course to avoid bad weather.
There was no distress call issued by Flight QZ8501, operated by Indonesian AirAsia, 49 percent owned by Malaysia-based budget carrier AirAsia (AIRA.KL), which has had no crashes since it started flying in 2002.
Singapore said it would send two planes to join the search for the missing Airbus (AIR.PA) A320-200 early on Monday, while the United States, Malaysia, Britain, South Korea, Australia and India offered help, from planes and navy boats to experts and investigators.
"We are deeply shocked and saddened by this incident," said Sunu Widyatmoko, CEO of AirAsia Indonesia. "We are cooperating with the relevant authorities to the fullest extent to determine the cause of this incident."
On board were 155 Indonesians, three South Koreans and one each from Singapore, Malaysia and Britain, plus a French pilot.
The pilot "was requesting deviation due to en-route weather before communication with the aircraft was lost", the airline said.
The pilots were experienced and the plane last underwent maintenance in mid-November, it said. The aircraft had accumulated about 23,000 flight hours in some 13,600 flights, according to Airbus.
QZ8501 fell out of contact with Jakarta air traffic control at 6:17 a.m. (2317 GMT Saturday). It was roughly halfway between Surabaya and Singapore when it went missing in bad weather, somewhere from Tanjung Pandan on Indonesia's Belitung island to Pontianak, in West Kalimantan, Borneo.
Malaysia AirAsia chief Tony Fernandes went to Surabaya to update dozens of relatives of passengers who waited anxiously. The carrier swapped its distinctive bright red logo for a grey background on its website and social media accounts.
"This is my worst nightmare," Fernandes said on Twitter. "But there's no stopping", he said of the search.
The incident caps a disastrous year for Malaysia-affiliated airlines. Malaysian Airlines Flight MH370 went missing on March 8 on a trip from Kuala Lumpur to Beijing with 239 passengers and crew on board and has not been found.
On July 17, the same airline's Flight MH17 was shot down over Ukraine, killing all 298 people on board.
Praying for passengers
Indonesia President Joko Widodo urged his people to pray for the safety of the passengers and crew. During his Sunday address at St. Peter's Square in the Vatican, Pope Francis said those on board were in his prayers.
The head of Indonesia's transport safety committee expressed hope of locating QZ8501 quickly and said it was too soon to detect the so-called electronic pings from its black box recorder.
"We are using our capacity to search on sea and land," Tatang Kurniadi told a news conference in Jakarta.
"Until now, we have not found out how the plane fell or what kind of emergency it was."
There was bad weather over Belitung at the time and the aircraft had been flying at 32,000 feet before asking to fly at 38,000 feet to avoid clouds.
Malaysia was sending vessels and a C130 aircraft while Singapore had also sent a C130. Australia had a P3 Orion aircraft on standby and India offered three navy boats.
Louise Sidharta was at Singapore's Changi Airport waiting for her fiancée to return from a family holiday. "It was supposed to be their last vacation before we got married," she said.
A man named Purnomo told TVOne in Surabaya of his lucky escape. "I should have been on the flight … but this morning I had an emergency. I had my passport in hand."
Like all affiliates of AirAsia, which include Thailand, the Philippines and India, Indonesia AirAsia operates Airbus jets, of which it has 30 of the A320 model.
AirAsia has ordered several hundred jets from the European planemaker, making it one of its most important customers. The missing plane has been in service for just over six years, according to airfleets.net.
Indonesian officials from the civil aviation authority and transport safety committee, which are responsible for crash investgiations, arrived in Surabaya on Sunday. A transport ministry official said Indonesia would handle the probe.
"The aircraft was registered in Indonesia and it looks to be missing over Indonesian territory, so we will lead the investigation," said the official, who asked not to be named as he was not authorised to speak to media.
"We have the expertise to do this."