On 6 December 2016, a Boeing 737-800 approaching Darwin at night in the vicinity of thunderstorm activity suddenly encountered very heavy rain just before landing which degraded previously good visual reference. After drifting right of centreline just before and after touchdown, the right main gear left the runway for 400 metres before regaining. The landing and taxi-in was subsequently completed. The Investigation attributed the excursion to difficulty in discerning lateral drift during the landing flare to an abnormally wide runway with no centreline lighting in poor night visibility and noted similar previous outcomes had been consistently associated with this context.