AirAsia Indonesia failed to brief the pilots of the doomed QZ8501 flight about the weather report, and the plane ultimately crashed into the Java Sea after encountering bad weather, a leaked document from the nation's met agency has revealed.
The news comes days after it came to light that AirAsia had flown the Surabaya-Singapore flight on an unauthorised schedule.
Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) had sent a document to the Transportation Minister last week, stating that the pilots of QZ8501 had not received the weather report that showed that the route was very cloudy.
The met agency had also released a report last Friday that weather charts before the flight's take-off on 28 December had indicated "worrying conditions".
"AirAsia took the [BMKG] weather report at 7 am," on 28 December (the plane took off at 5.35 am), BMKG head Andi E. Sakya said in the letter, according to The Jakarta Post.
An AirAsia flight operations officer (FOO) reportedly received the weather report only after the plane lost contact with Jakarta air traffic control at 6:17 am.
According to standard procedure, pilots are required to get the weather report at least ten minutes before takeoff.
"According to standard procedures, every time pilots chart flight plans, they must consider [BMKG] weather reports. So how could the plane fly without a weather report from the agency?" Former National Transportation Safety Committee (KNKT) investigator Ruth Hanna Simatupang told The Jakarta Post.
However, AirAsia Indonesia head Sunu Widyatmoko has denied the allegations of violations of protocol.
"AirAsia Indonesia really considers and is very careful in evaluating weather reports from the BMKG before every flight," he said.
AirAsia Indonesia also flouted the schedule by flying its plane on Sunday, though it is authorised to use the Surabaya-Singapore route only on Mondays, Tuesdays, Thursdays, and Saturdays.
Indonesia's Transport Ministry said it was possible to revoke AirAsia's license for flying on an unauthorised schedule, and is set to begin investigation of all AirAsia Indonesia flight schedules from Monday.
"You should abide by the regulation. Don't even try to break the rules. I can revoke your license," Transportation Minister Ignatius Jonan had said.
The airliner's permit to ply planes on the route will remain frozen till further investigation, officials have said.
The AirAsia plane crashed in the Java Sea on Sunday a little after take-off, with 162 people on board.