A plane in Indonesia strayed off its course after both pilots of the aircraft fell asleep for 28 minutes, according to a report released by the National Transportation Safety Committee (KNKT), a government agency.
The Indonesia Transport Ministry will launch an investigation into the incident that took place on January 25.
According to the KNKT preliminary report, both the pilot and the co-pilot of the Batik Air BTK6723 fell asleep during a flight from Kendari in Southeast Sulawesi province to Indonesian capital Jakarta. However, none of the 153 passengers and four flight attendants on board the plane were injured during the flight, and the aircraft did not suffer any damage either.
Later, the flight - which lasted two hours and 35 minutes - successfully landed in Jakarta.
According to the KNKT report, the aircraft was scheduled to go from Jakarta to Kenderi, and then return. During the flight preparation in Jakarta on January 25, the co-pilot had notified his pilot that he had not had "proper rest". After the plane cruised at an altitude of 36,000 feet, the pilot asked the co-pilot to take rest, and he slept for "about 30 minutes" inside the cockpit. The co-pilot (also known as the second-in-command pilot) woke up before the plane began descending to Kenderi.
During transit, both the pilots ate "instant noodle cups in the cockpit"
After the BTK6723 aircraft departed from Kenderi, and reached a cruising altitude, the pilot (also known as pilot-in-command) sought permission to sleep from the co-pilot, which he was granted. A few seconds later, the pilot slept off and the co-pilot took over as the 'pilot monitoring (PM)'.
The pilot, however, woke up some time later and asked if the co-pilot wanted to take some rest. Upon the co-pilot's decline, the pilot continued to sleep.
Around 90 minutes into the flight, when the pilot remained asleep, and the co-pilot was acting both as 'pilot flying' and 'pilot monitoring', the co-pilot "inadvertently fell asleep", according to the KNKT report.
Around 12 minutes after the last recorded transmission from the co-pilot, the Jakarta area control center (ACC) tried to contact the BTK6723 pilots, but there was no reply from them. The Jakarta ACC also got other pilots to call the Batik Air pilots, but to no avail.
Nearly 28 minutes later, the pilot woke up and was aware that the "aircraft was not in the correct flight path". At this point, he woke up the co-pilot, and told the ACC that the flight had experienced a "radio communication problem" which had been resolved.
The flight was then safely landed in Jakarta.
The KNKT report did not reveal the names of the pilots, but identified the pilot as a 32-year-old and the co-pilot as a 28-year-old - both Indonesian males. The co-pilot had one-month-old twins and "had to wake up several times to help his wife take care of the babies", the report added.
The Indonesia Transport Ministry will conduct a probe into the incident, state news agency Antara, citing the civil aviation director-general M Kristi Endah Murni, said.
"We will conduct an investigation and review of the night flight operation in Indonesia regarding the Fatigue Risk Management for Batik Air and other flight operators," Murni added.
She further stated that flight crews of BTK6723 have also been grounded according to the Standard Operating Procedure (SOP) pending further investigation.
