The New Zealand Transport Accident Investigation Commission (TAIC) concluded that stress factors caused a pilot to descend below decision height while on approach to Christchurch Airport in poor visibility conditions.
On Saturday 29 October 2011, an Air New Zealand Boeing 737-300 was on a flight from Auckland to Christchurch with six crew and 128 passengers on board. The captain was the “pilot flying” and the first officer was the “pilot monitoring”. A check captain was also on the flight deck. He was conducting an annual route check on the captain.
When the flight departed Auckland the forecast weather conditions for Christchurch were favourable for a successful landing. However, the weather conditions at Christchurch deteriorated en route, with low cloud and fog restricting visibility on the approach path to the runway.
The airplane made a standard instrument approach to the runway from the south. The procedure allowed the airplane to descend to the decision height of 200 feet above the ground.
The airplane was still in cloud/fog when it reached a height of 200 feet, but the captain did not initiate a missed approach. Both the first officer and the check captain were about to intervene when the runway approach lights became visible at a height of about 100 feet. The captain then landed the airplane.
A pilot not initiating a missed approach when they do not have the required visual reference at decision height is a safety issue. Before reaching the decision height, the captain had failed to respond to two other procedural check calls, and these two failures went unchallenged by the first officer, which is another safety issue.
TAIC determined that the captain did not comply fully with the procedures and perform the mandatory missed approach because he was under stress brought on by a combination of factors comprising:
– the Canterbury earthquakes and their aftershocks
– personal health issues
– anxiety associated with the route check flight.
The Commission also determined that the captain’s failure to respond on two occasions should have been picked up and challenged by the first officer before the airplane reached the decision height.