On 27 July 2021, an Airbus A320 departed uneventfully at night from runway 20L at Changi as cleared despite the crew observing that runway lighting was not as they expected. The Investigation concluded that the runway had been completely unlit and that it was likely that both the pilots and the controller involved had been affected by ‘expectation bias’ in respect of their perception that the lighting had been either as normal (the controller) or partially on (the pilots). Some issues with controller direct or display visibility of lighting status were also identified.