JAKARTA (Jakarta Post/Asia News Network) - Leaked official documents have given rise to allegations that AirAsia Indonesia violated procedures which resulted in the pilots of doomed flight QZ8501 not receiving a required weather report before takeoff.

The allegation comes on the heels of a revelation on Saturday that the airline did not have permission to operate the Surabaya-Singapore flight on Sundays. The ill-fated flight took off on the morning of Dec 28, a Sunday, before crashing into the Java Sea mid-way through its scheduled two-hour journey to Singapore.

In a leaked document that was originally sent by Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) to Transportation Minister Ignatius Jonan on Wednesday, an AirAsia flight operations officer (FOO) received the required report from BMKG only after the plane lost contact with Jakarta air traffic control at 6:17 am.

"AirAsia took the [BMKG]weather report at 7 am," on Dec 28, BMKG head Andi E. Sakya said.

The plane had departed from Surabaya's Juanda International Airport at 5:35 am. Former National Transportation Safety Committee (KNKT) investigator Ruth Hanna Simatupang said that pilots were required to obtain weather reports from the BMKG at least 10 minutes before takeoff.

"According to standard procedures, every time pilots chart flight plans, they must consider [BMKG]weather reports," she said. "So how could the plane fly without a weather report from the agency?"

Hanna said one factor might be the early-morning departure.

"The flight departed really early in the morning and the crew had to get ready at least 2.5 hours before that because it was an international flight. Did Juanda airport prepare the crew at 4 am? That may be why the FOO didn't take the weather report from the BMKG. Or it could be the BMKG did not have its officials (ready)," said Hanna.

Sunu Widyatmoko, the president director of AirAsia Indonesia, which is an associate carrier of Malaysian budget airline AirAsia, denied the allegation.

"AirAsia Indonesia really considers and is very careful in evaluating weather reports from the BMKG before every flight," he said.

Sunu said the BMKG's station at Soekarno-Hatta International Airport sent reports via e-mail four times a day to the AirAsia Indonesia operations center.

"These reports are accepted by the operations control centre at all AirAsia Indonesia hubs, which are Jakarta, Medan, Surabaya, Bandung and Denpasar, where they are printed out and kept by pilots," he said.

The agency's weather map shows that the Surabaya-Singapore route taken by the flight on that day was very cloudy, lending support to the theory that thick cumulonimbus clouds contributed to the crash.

The Transportation Ministry had already grounded AirAsia flights from Surabaya to Singapore following its finding that the airline did not have permission to fly on Sundays.

The suspension, effective from Jan. 2, will be in place until the KNKT completes its investigation.

AirAsia Indonesia safety and security director Achmad Sadikin has denied the flight was unauthorised.

Hanna said that AirAsia Indonesia might have obtained a licence to fly outside its regular schedule, considering the high demand for year-end travel.

"There must have been a new licence proposed by AirAsia to the ministry. We must check how it could obtain such a permit and what did it take to get it?" Hanna said.

The Transportation Ministry's acting director-general for air transportation, Djoko Murjatmodjo, said on Saturday the ministry would investigate any irregularities.

"We know (someone) must have given the permit. We're looking into the who and why," he said, adding that those responsible for possible violations might be suspended.

Responding to the allegations, Transportation Minister Ignasius made an unannounced visit to the AirAsia Indonesia office in Cengkareng, Tangerang, on Friday.

Jonan reportedly expressed anger after learning some AirAsia Indonesia pilots had not been directly briefed by the FOO on weather conditions.

The minister was said to have been disappointed with a statement from AirAsia officials that said pilots could download information from the BMKG's website.

"You should abide by the regulation. Don't even try to break the rules. I can revoke your licence," Jonan said.

Meanwhile in Surabaya, some family members of passengers on the AirAsia flight said they had not considered filing a lawsuit following the allegations.

"We're focusing now on finding information about Adrian," said Ronny Tanubun, a relative of 13-year-old Andrian Fernando, one of the passengers on the plane.