Two pilots from an Indonesian airline are facing criticism following the revelation in an incident report that both of them fell asleep during a January flight with over 150 people on board.

The pilots were reportedly unreachable for about half an hour, awakening to discover that the aircraft had deviated from its intended course, as outlined in the report.

The incident transpired during a roundtrip Batik Air Indonesia flight between Halu Oleo Airport in Kendari and Soekarno-Hatta International Airport in Jakarta on January 25.

While preparing for the initial leg of the flight from Jakarta to Kendari, the second-in-command pilot, a 28-year-old with approximately 1,600 hours of flying experience, informed the pilot in command that he hadn’t had sufficient rest, according to the report by Indonesia’s National Transportation Safety Committee.

In response, the commanding pilot, a 32-year-old with around 6,300 hours of flying experience, permitted the second pilot to rest for about half an hour during that leg of the journey.

On the return flight to Jakarta, carrying 153 passengers and four flight attendants, the commanding pilot, who had rested during the first leg, asked the second pilot if he could take a turn to rest, which was granted.

After a while, the commanding pilot woke up and offered the other pilot a chance to nap, but they declined, CBS News reported.

Approximately 20 minutes later, according to the incident report, the second pilot “inadvertently fell asleep” while the aircraft was at an altitude of approximately 36,000 feet.

Attempts by air traffic controllers and other pilots to contact the sleeping pilots were unsuccessful.

The commanding pilot woke up 28 minutes after the last recorded transmission and immediately realized that the aircraft was not following the correct flight path.

“The PIC [pilot in command] then saw the SIC [second in command] was sleeping and woke him up,” the report says. “About the same time, the PIC responded to the call from another pilot and Jakarta ACC. The PIC advised the Jakarta ACC that BTK6723 experienced radio communication problem and currently the problem has been resolved. The flight then continued and landed at Jakarta uneventfully.” 

Investigators said nobody was injured and the aircraft was not damaged. 

Written by B.C. Begley