According to The West Australian:
The Brisbane to PerthQF943 flight was scheduled to land in Perth at 11.50pm, instead it was diverted to the Goldfields town due to strong winds on approach into the capital.
While on the tarmac, where the 737 which has capacity for 174 passengers was refuelled, a mechanical issue was detected which meant the plane could not continue to Perth.
A replacement aircraft has been sent to Kalgoorlie and passengers have boarded and are due to depart for Perth shortly.There was no accommodation available in Kalgoorlie so passengers spent the night in the terminal. It is understood passengers were offered breakfast at the airport.
METARs for the relevant period:
METAR YPPH 281730Z 09011KT CAVOK 18/09 Q1017=
METAR YPPH 281700Z 05009KT CAVOK 18/08 Q1017=
METAR YPPH 281630Z 06011KT CAVOK 19/08 Q1017=
METAR YPPH 281600Z 06010KT CAVOK 19/07 Q1016=
METAR YPPH 281530Z 07009KT 040V120 CAVOK 20/07 Q1017 RF00.0/000.0=
METAR YPPH 281500Z 08009KT 020V130 CAVOK 20/07 Q1017 RF00.0/000.0=
TAFs for the relevant period:
TAF YPPH 281407Z 2815/2918 08010KT CAVOK FM281700 09017G28KT CAVOK FM290200 09014KT CAVOK FM291500 10015G25KT CAVOK=
TAF YPPH 281121Z 2812/2918 08012KT CAVOK FM281700 09017G28KT CAVOK FM290200 09014KT CAVOK FM291500 10015G25KT CAVOK=
TAF YPPH 280805Z 2809/2912 07012KT CAVOK FM281700 09017G28KT CAVOK FM290200 09014KT CAVOK=