At 0300 MYT there was a changeover in the Controllers at KL ATCC.
At 0000 MYT (midnight and prior to the departure of MH370) the number of Controllers in the KL ATSC was scaled down by half to enable the Controllers to take a scheduled 3-hour break from duty. At 0300 MYT the first group of Controllers returned from their break and the second group started their break which would last until 0600 MYT.
Safety Investigation Report MH370/01/2018 2.2.8 ATS Operational Issues after Last Radio Communication with MH370 and subsequent ATS Activities/Actions
m) KL ATSC Duty Shift System for Air Traffic Controllers
ii) Operations in Restricted/Collapsed Mode
(1) From 1600 UTC [0000 MYT] until 2200 UTC [0600 MYT] the number of Controllers in the KL ATSC was scaled down by half to enable the Controllers to take a scheduled break from duty:
- the first group from 1600 UTC [0000 MYT] to 1900 UTC [0300 MYT] and
- the second group from 1900 UTC [0300 MYT] to 2200 UTC [0600 MYT].
This practice had been approved by DCA. According to DCA, the scale-down of personnel during lean hours is a norm in air traffic control centres all around the world where air traffic services can continue safely.