An Indonesian naval patrol vessel has found what could be the tail of a crashed AirAsia passenger jet, the section where the crucial black box voice and flight data recorders are located, officials said on Monday.
News of the possible breakthrough came as the transport ministry in Jakarta said some officials on duty at the time of the accident will be moved to other roles. It also announced it was tightening rules on pre-flight procedures.
Ships and aircraft scouring the northern Java Sea for debris and bodies from the Airbus A320-200 have widened their search to allow for currents eight days after Flight QZ8501 plunged into the water en route from Indonesia's second-biggest city of Surabaya to Singapore with 162 people on board.
"We found what has a high probability of being the tail of the plane," Yayan Sofyan, captain of the patrol vessel, told reporters.
He was speaking after his ship returned to the port in Surabaya on Monday, and it was not immediately clear if he was referring to one of the five large objects pinpointed by search vessels over the weekend.
Indonesia's meteorological agency has said seasonal tropical storms probably contributed to the December 28 crash and the weather has persistently hampered efforts to recover bodies and find the cockpit voice and flight data recorders that should explain why the plane crashed into the sea.
The recorders are housed in the tail section of the Airbus, making retrieval of that part of the aircraft crucial.
"I am not saying it's the tail yet," the head of Indonesia's search and rescue agency, Fransiskus Bambang Soelistyo, told a news conference in Jakarta. "That is suspected. Now we are trying to confirm it."
Transport ministry crackdown
The transport ministry said some officials at the country's airport operator and air traffic control agency who were involved with the AirAsia flight will be moved to other duties while the accident investigation is completed.
The ministry gave no reason.
It also said that, three days after the crash, it had issued a directive making it mandatory for pilots to be briefed in person by an airline official on weather conditions and other operational issues before every flight.
"A circular has been signed by the transport ministry on December 31, stating that pilots must have a face-to-face briefing with a flight operation officer so the briefing officer will know the pilot is in a healthy condition and so on," said Djoko Murjatmodjo, acting director general of air transportation.
Aviation experts said this was a common practice in the industry, but it was not immediately clear if it has been normal procedure in Indonesia.
The main focus of the search is about 90 nautical miles off the coast of Borneo island, where five large objects believed to be parts of the plane - the largest about 18 metres (59 feet) long - have been located in shallow waters by ships using sonar.
While experts say the shallow sea should make the recovery fairly straightforward in good weather, strong winds and big waves have frustrated the multinational force of ships and divers that has converged at the site.
"The seas haven't been very friendly, but the black boxes have a 30-day life and they will be able to find them," said Peter Marosszeky, a senior aviation research fellow at the University of New South Wales in Sydney. "It's the weather that is causing the delay."
Thirty-seven bodies of the mostly Indonesian passengers and crew have been recovered, including some still strapped in their seats. Many more may be trapped in the body of the aircraft.
Indonesia AirAsia has come under pressure from authorities, who have suspended its Surabaya-Singapore licence, saying the carrier only had permission to fly the route on Mondays, Tuesdays, Thursdays and Saturdays. Flight QZ8501 took off on a Sunday.
"Please differentiate between the probe into flight licences and the air crash investigation," he said.
Singapore's civil aviation authority and its Changi Airport Group said AirAsia had the necessary approvals to operate a daily flight between Surabaya and Singapore.
Indonesia AirAsia is 49% owned by Malaysia-based budget carrier AirAsia, whose shares fell nearly 5% on Monday.
While the licence investigation could have serious consequences for the airline's operations, insurance industry experts said insurers were expected to pay claims whether or not the airline was properly licensed to fly on the day.
The crash was the first fatal accident suffered by the AirAsia budget group, whose Indonesian affiliate flies from at least 15 destinations across the archipelago.