JAKARTA—Indonesia focused rescue efforts on Sulawesi island on Tuesday after an Adam Air Boeing 737-400 plane went missing with 96 passengers and six crew on board.
The plane lost contact with the ground on Monday about an hour before it was due to land in Manado in North Sulawesi, Tatang Ikhsan, director general at the transport ministry, said. It had been flying at 35,000 feet (10,670 metres).
An official said efforts to reach the co-pilot by mobile telephone indicated the plane was on the ground rather than in the sea, where the telephone would be unlikely to work.
"There was a ring tone, but no answer," said Abdul Gani, a Search and Rescue duty officer at Makassar, capital of the region from where a distress signal was picked up by satellite.
Speaking to Reuters by telephone, Gani said the signal indicated the plane might be in a mountainous area. Air and sea searches would begin in the morning, he said.
Ikhsan said the flight had originated in Jakarta, taken off from a stopover in Surabaya on Java island at 1 p.m. (0600 GMT) and been scheduled to land just over two hours later in Manado.
At a news conference late on Monday he said the satellite, in Singapore, had dectected the distress signal 83 nautical miles (154 km) northwest of Makassar, the capital of South Sulawesi province, 1,400 km (870 miles) east of Jakarta.
"We call on other flights which crossed this route to provide information on any distress signal," he said.
Transport Minister Hatta Rajasa said the plane had been sighted by another plane above the Mamuju forest on Sulawesi.
"Let's hope it made an emergency landing," he told Elshinta radio, adding that rescuers had been sent to the area.
At Jakarta's main commercial airport, where the flight began its journey, taxi driver Oswald Mamalani told Reuters his younger sister and her child were aboard the plane.
"When I arrived home, I got a phone call from a relative in Manado asking me to pray... for the safety of my sister," he said. "So far I feel that my sister is still alive."
Weather Warning
First Marshal Eddy Suyanto, commander of Hasanuddin air base in Makassar, told Metro television: "We have contacted related agencies and several groups have travelled by road to locations where we think the plane might have gone down but so far there has not been any information."
The transport ministry's Ikhsan said the plane was airworthy and last serviced in December 2005. It has 45,371 flying hours, and according to Adam Air the 17-year-old aircraft's engines are CFM56-3C1 models made by General Electric.
"The weather conditions all over our country are not very good. We have notified all airlines... All flights should have received complete information," he said.
Much of Indonesia was cloudy with rainfall on Monday.
An Adam Air Boeing 737-300 plane was forced to make an emergency landing in February at a small airport in East Nusa Tenggara province after a navigational failure caused the pilot to lose contact with the destination airport in Makassar.
Adam Air, one of about a dozen budget airlines in the world's fourth most populous nation, operates 19 Boeing The airline was established by two Indonesians, Agung Laksono, the speaker of the house of representatives, who is chairman of the company, and Sandra Ang, in 2002 and commenced operations on Dec. 19, 2003.
In January a newspaper report said Adam Air was planning a share listing in Singapore for 2008.
Air travel in Indonesia, home to 220 million people, has grown substantially since the liberalisation of the airline industry after the Asian financial crisis in the late 1990s, which enabled privately owned budget airlines to operate.
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