TAIPEI (AFP/REUTERS) - Taiwan rescuers scoured a river for 12 people still missing from a TransAsia plane crash on Thursday as the pilot was hailed as a hero for apparently battling to avoid hitting built-up areas shortly after issuing a "mayday" call.

TransAsia identified the pilot as 42-year-old Liao Chien-tsung. He and the co-pilot of the almost-new turboprop ATR 72-600 were among those killed, Taiwan's Civil Aeronautics Administration (CAA) said.

Both the pilots' bodies have been recovered, TransAsia said on Thursday.

Mr Liao was applauded by aviation experts for apparently steering the plane away from populated areas and high-rise buildings to avoid causing more damage with the aircraft, which had 53 passengers and five crew on board.

Taiwanese media reported that it appeared that Mr Liao had fought desperately to steer his stricken aircraft between apartment blocks and commercial buildings close to Taipei's Songshan airport before crashing into the river.

The head of Taiwan's CAA, Mr Lin Tyh-ming, has said Mr Liao had 4,916 flying hours under his belt, and the co-pilot 6,922 hours.

Taiwanese media reported that Mr Liao came from a poor family.

The son of two street vendors, he studied hard before passing exams to join Taiwan's air force. He later flew for China Airlines, Taiwan's main carrier, before joining TransAsia.

"Based on the flight path, the pilot deviated and tried to avoid obstacles. The pilot apparently made a conscious effort to avoid further and unnecessary casualties by ditching in the river. It was a very courageous move," Hong Kong-based aviation analyst Daniel Tsang told AFP.

Emotional citizens posted their praise and condolences on social media sites.

"I believe the pilot managed to steer the plane away from high-rise buildings, he is a hero," Ms Gin Oy, a writer and actress, said on her Facebook page.

The Apple Daily newspaper ran a front-page story headlined thanking "the pilot for saving Taipei".

"Pilot Liao Chien-tsung struggled to avoid high-rise buildings to find a site to crash land along Keelung river to reduce casualties. Many netizens thought the judgement he made in an instant saved numerous people on the ground," it said.

"We are proud of him. He was very brave to avoid the buildings," Mr Liao's aunt told reporters at a funeral home in Taipei.

Taiwan President Ma Ying-jeou was scheduled to pay his respects to the victims at a funeral home and visit the wounded at several hospitals later on Thursday, his office said.

Tales of miracle escapes emerged, as television footage showed a father cuddling his toddler son as they were taken to shore by boat after being rescued on Wednesday.

Together with the child's mother, the family had switched seats on the plane "out of a hunch" that saved their lives, the United Daily News said.

"The family originally sat in the heavily damaged left side but Lin Ming-wei felt uneasy after he heard noises before taking-off and requested to switch seats," the report quoted Mr Dai Bi-chin, a friend of the family, as saying after visiting them in hospital.

Their new seats put them next to a crack in the plane after it crashed, and the newspaper said Mr Lin was able to pull his wife to safety and then revive his son after spotting him in the water, blue and unresponsive.

"My brother just can't live without his son. When he found him, after lying in cold water for three minutes and with no signs of breathing or heartbeat, he performed CPR. He brought his son back," survivor Mr Lin's brother Lin Ming-yi told reporters.

Hundreds of rescuers in boats, as well as divers and soldiers mounted the search in the chilly waters, as the death toll rose to 31 with more bodies located, including those of the pilot and co-pilot, the authorities said.

The TransAsia ATR 72-600 crashed shortly after take-off from Songshan Airport in northern Taipei on Wednesday, hitting an elevated road as it banked sidelong towards the Keelung River, leaving a trail of debris including a smashed taxi.

The CAA has grounded a total of 22 ATR planes from two Taiwanese airlines for safety checks after the accident on a domestic route to the island of Kinmen - the second fatal crash for TransAsia after 48 people were killed in July.

"This morning we have some 60 divers going underwater to search" in addition to 20 boats scouring the river, said Mr Liu Yung-chou, an official from the national fire agency, which is coordinating the rescue operation.

Desperate crew shouted "Mayday! Mayday! Engine flameout!" as the plane plunged out of the sky, according to a recording thought to be the final message from the cockpit to the control tower played on local television.