aeroplane
Illustrative image. The incident resulted in a series of navigation errors, but the Batik Air airline flight's 153 passengers and four flight attendants were unharmed during the two-hour-and-35-minute flight. Image Credit: Pixabay

Jakarta: Indonesia's transport ministry said Saturday it would open a probe into local airline Batik Air after two of its pilots were found to have fallen asleep during a recent flight.

A pilot and co-pilot were simultaneously asleep for approximately 28 minutes during a flight from South East Sulawesi to the capital Jakarta on January 25, a preliminary report by the National Transportation Safety Committee (KNKT) said.

The incident resulted in a series of navigation errors, but the Airbus A320's 153 passengers and four flight attendants were unharmed during the two-hour-and-35-minute flight.

The transport ministry "strongly reprimands" Batik Air over the incident, air transport director-general M. Kristi Endah Murni said, calling on airlines to pay more attention to their air crew's rest time.

"We will carry out an investigation and review of the night flight operation in Indonesia related with Fatigue Risk Management for Batik Air and all flight operators," Kristi said in a statement.

Batik Air said in a statement on Saturday that it "operates with adequate rest policy" and that it was "committed to implement all safety recommendation".

The pilots involved in the January 25 incident had been temporarily suspended, the statement added.

A spokesperson of Lion Air Group, which comprises Batik Air, did not immediately respond to AFP's request for comment.

The KNKT report, seen by AFP on Friday, was uploaded to the agency's website in late February.

One of the pilots had not rested adequately on the night before the flight, according to the report.

About half an hour after the plane took off, the captain asked permission from his second-in-command to rest for a while, with the request being granted.

The co-pilot then took over command of the aircraft, but also inadvertently fell asleep, the report said.

"The second-in-command had one-month twin babies. His wife took care of the babies and he assisted while at home," the report said.

A few minutes after the last recorded transmission by the co-pilot, the area control centre in Jakarta tried to contact the aircraft. It received no answer.

Twenty-eight minutes after the last recorded transmission, the pilot woke up and realised his co-pilot was asleep and that the aircraft was not on the correct flight path.

He immediately woke his colleague up, responded to the calls from Jakarta and corrected the flight path, the report said.

The plane landed safely after the incident.

Investigators did not identify the pilots, but said they were both Indonesians and were aged 32 and 28.