A body recovered from the crashed AirAsia plane was wearing a life jacket, raising new questions about how the disaster unfolded.

Seven bodies have been recovered from the sea, some fully clothed, which could indicate the Airbus A320-200 was intact when it hit the water. That would support a theory that it suffered an aerodynamic stall.

The fact that one person put on a life jacket suggests those on board had time before the aircraft hit the water, or before it sank. And yet the pilots did not issue a distress signal.

AirAsia Flight QZ8501 bodies
Members of a search and rescue team run with the body of an AirAsia flight QZ8501 passenger at Iskandar airbaseBeawiharta/Reuters
AirAsia Flight QZ8501 bodies
A helicopter is seen behind three covered bodies recovered from the AirAsia plane, on the deck of KRI Bung Tomo warshipAntara Photo Agency/Reuters
AirAsia Flight QZ8501 bodies
Members of the Indonesian Air Force carry a coffin containing the body of a passenger who was on AirAsia flight QZ8501 at Iskandar air base in Pangkalan Bun district, IndonesiaBeawiharta/Reuters
AirAsia Flight QZ8501 bodies
A coffin of a victim of AirAsia flight QZ8501 is transferred from a local hospital in Pangkalan BunAFP

Authorities in Surabaya were making preparations to receive and identify bodies, including arranging 130 ambulances to take victims to a police hospital and collecting DNA from relatives.

Most of those on board were Indonesians. No survivors have been found.

AirAsia Flight QZ8501
Government security officials carry a relative who collapsed at Juanda International Airport after rescuers announced they had seen bodies and luggage off the coast of BorneoBeawiharta/Reuters
AirAsia Flight QZ8501 bodies
Relatives of AirAsia QZ8501 passengers take part in the identification process at Juanda International Airport in SurabayaRobertus Pudyanto/Getty Images

Rescuers believe they have found the plane on the ocean floor off Borneo, after sonar detected a large, dark object beneath the water near where debris and bodies were found on the surface.

Ships and planes had been scouring the Java Sea for flight QZ8501 since Sunday (28 December), when it lost contact during bad weather about 40 minutes into its flight from the Indonesian city of Surabaya to Singapore.

A pilot who works for a Gulf carrier said the life jacket indicated the cause of the crash was not "catastrophic failure". Instead, the plane could have stalled and then come down, possibly because its instruments iced up and gave the pilots inaccurate readings.

"There was time. It means the thing didn't just fall out of the sky," said the pilot, who declined to be identified.

AirAsia Flight QZ8501 search
A passenger's relative reacts after seeing an unidentified floating dead body during a search and rescue mission with Indonesian military personnel over the Java Sea for the missing AirAsia flight QZ8501Juni Kriswanto/AFP
AirAsia Flight QZ8501 body bags
Members of a search and rescue team carry body bags to a waiting aircraft on Bangka Island, IndonesiaEd Wray/Getty Images
AirAsia Flight QZ8501 debris
Members of a search and rescue team carry debris recovered from the seaAntara Foto/Kenarel/Reuters
AirAsia Flight QZ8501 debris
Members of the Indonesian Air Force show items retrieved from the Java Sea during search and rescue operations for the missing AirAsia flight QZ8501Bay Ismoyo/AFP
AirAsia Flight QZ8501 search
Indonesian Navy airmen search the waters near Bangka Island for debrisEd Wray/Getty Images
AirAsia Flight QZ8501 search
Indonesian Navy divers, part of a search effort for AirAsia Flight QZ8501, transport scuba gear to a waiting plane on Bangka IslandEd Wray/Getty Images

Strong wind and waves have hampered the search. "We are all standing by," Dwi Putranto, heading the air force search effort in Pangkalan Bun, told Reuters.

"If we want to evacuate bodies from the water, it's too difficult. The waves are huge and it's raining."