1103 GMT January 27, 2021
Flight tracking data showed the Sriwijaya Air Boeing 737-500 plunged into a steep dive about four minutes after it left Soekarno-Hatta International Airport, AFP reported.
Sixty-two passengers and crew were on board, including 10 children, Transport Minister Budi Karya Sumadi told reporters.
The suspected crash site is near tourist islands just off the coast of Indonesia's sprawling capital.
The plane took off on Saturday afternoon and a search and rescue operation began with no official results available on Saturday night.
"We deployed our team, boats and sea riders to the location suspected to be where it went down after losing contact," Bambang Suryo Aji, a senior official at the agency, told reporters after nightfall.
Sriwijaya Air flight SJ182 was bound for Pontianak on Indonesia's section of Borneo island, about 90 minutes flying time over the Java Sea.
"I have four family members on the flight -- my wife and my three children," Yaman Zai said as he sobbed at Pontianak airport.
"They haven't arrived. They're not here," he was heard saying as he spoke on his mobile phone.
Data from FlightRadar24 said the plane reached an altitude of nearly 11,000 feet (3,350 meters) before dropping suddenly to 250 feet. It then lost contact with air traffic control.
"Sriwijaya Air flight #SJ182 lost more than 10,000 feet of altitude in less than one minute, about 4 minutes after departure from Jakarta," the tracking agency said on its official Twitter account.
Broadcaster Kompas TV quoted local fishermen as saying they had found debris near islands just off the coast of the capital Jakarta, but it could not be immediately confirmed as having belonged to the missing jet.
Authorities and the airline gave no immediate indication as to why the plane suddenly went down.
The budget airline, which has about 19 Boeing jets that fly to destinations in Indonesia and Southeast Asia, said only that it was investigating the loss of contact.