On 31 March 2014, an Airbus A320 departed Auckland, New Zealand for a scheduled passenger flight to Gold Coast, Queensland. On departure from Auckland, the local barometric pressure (QNH) was 1025 hPa, and the crew had selected ‘STD’ for the standard atmospheric pressure of 1013 hPa on the altimeters during climb to flight levels.
During the cruise, about 15 minutes prior to commencing the descent for the Gold Coast, the crew obtained the automatic terminal information service (ATIS) for Gold Coast and the captain wrote the details onto the take-off and landing data (TOLD) card. The crew then conducted the approach briefing, including a review of this information, which was entered into the flight management guidance computer (FMGC) for the approach.
Approaching transition altitude, the ‘BARO REF’ warning flashed however the captain was communicating with ATC, hence the page in the FMGC with the QNH displayed was not selected. The first officer glanced at the TOLD card, and entered 1025 into the altimeter, possibly inadvertently interpreting either the cloud (025) or the temperature (25) as the QNH, instead of 1018.
The captain then completed the communication with ATC and commenced the transition check by stating ‘transition’. At this time the captain omitted to select the FMGC onto the flight plan page to display the QNH that had been entered. The first officer stated ‘set QNH 1025’ and the captain entered that into the second altimeter and the first officer entered the same value into the standby altimeter and a cross check confirmed that all three altimeters matched.
Passing about 1,000 ft AMSL, as the first officer completed the turn onto final, he observed the T-VASIS indicating a ‘fly-up’ profile. The RADALT callout of 500 ft sounded and the first officer realised that the approach path was incorrect. When at about 159 ft above ground level, the enhanced ground proximity warning system (EGPWS) ‘TERRAIN’ warning sounded, and the first officer commenced the missed approach. The captain first officer checked the QNH on the TOLD card and realised an incorrect QNH had been set.
This incident highlights the impact distractions can have on aircraft operations, particularly during a critical phase of flight.