The Royal New Zealand Air Force has changed its procedures following a difficult landing in near white-out conditions in Antarctica with a plane low on fuel and carrying 130 people, including a Government minister.
A Transport Accident Investigation Commission (TAIC) report into the October 2013 landing, which forced crews to make the attempt three times, finally landing using a lower minimum descent altitude, was released today and recommended a review of risk management.
The New Zealand Defence Force (NZDF) has since released a statement saying the findings were in line with its own internal review, and changes to its risk assessment for future flights and meteorological data have already been implemented.
"We support the findings of the TAIC report, which have confirmed that our operating procedures for Antarctic flights are robust and appropriate, and has revalidated the decision-making process by the crew for this flight," Chief of Air Force Air Vice-Marshal Mike Yardley said.
"The findings are consistent with the investigation we carried out and the changes we made, following the landing, as part of our normal flight safety procedures.
"We've engaged actively and openly with the TAIC as they carried out their independent investigation, and it is pleasing that both investigations confirm the quality of the training provided to our personnel."
The report followed an inquiry into the landing of a Royal New Zealand Air Force Boeing 757 at Pegasus Field aerodrome in Antarctica in October 2013.
There were 117 passengers and 13 crew on board, including Minister of Foreign Affairs Murray McCully, staff from the Ministry of Foreign Affairs and Trade, and staff from Antarctica New Zealand and the United States Antarctic Program.
At the time, Mr McCully described the situation as "not a very good situation to be in".
"It was pretty scary and not a great place to be...".
Air Vice-Marshal Yardley said the TAIC report showed the flight personnel had "demonstrat[ed] considerable skill and professional airmanship appropriate to the situation".
"The report confirms that the preparation and training given to Defence Force pilots and crews is world class, and that they are prepared for the situations that can arise in flight," Air Vice-Marshal Yardley said.
The aircraft's captain, Squadron Leader Grant Rhind, had been given a Green Endorsement to recognise his sound decisions, adherence to regulations, and his skill and leadership on the day, Air Vice-Marshal Yardley said.
The report said crew on board the flight from Christchurch received reports that the weather had deteriorated at Pegasus Field and a fog bank was lying over the runway and surrounding area.
The plane did not have enough fuel to complete the return trip and had passed the point of safe return, so the crew continued on to Pegasus Field despite the conditions.
The report found the crew made two attempts to land at Pegasus Field but fog restricted their visibility.
After the first attempt crew waited two hours for the weather to clear before making a second attempt at landing using a lower minimum descent altitude.
The landing was aborted and a missed approach procedure was initiated.
The report said fuel on board the aircraft was dwindling and the crew chose to make a third attempt at landing using the lower minimum descent altitude.
When the aeroplane was about 110 feet above the runway, crew saw the runway approach lights and markings, and were able to make a successful landing in near whiteout conditions.
There was no damage to the aeroplane and no one was injured.
Prior to departing, the crew had gathered additional information on the weather forecast at Pegasus Field, and were told the fog bank was 5km from the runway.
The commission found that observed and forecast weather conditions as reported to the crew met the criteria for the crew to continue past the point of safe return.
It also found there was no safe alternative, and the actions of the crew in proceeding below the allowable "minimum descent altitude" for the aerodrome was appropriate.
However, the commission found the risk assessment procedures undertaken when considering the suitability of the Boeing 757 aircraft for Antarctic operations had not taken into consideration five key points.
These key points included the potential consequences of the weather deteriorating.
The commission said weather conditions such as the presence of low cloud and fog below the main cloud base should always be considered when choosing to continue with a flight.
It was also found there was an increased likelihood of weather conditions deteriorating below minimum descent altitude in the summer season, and the accuracy of instrument approaches should be treated with caution prior to re-calibration flights being conducted early in the summer season.
The commission also found the aircraft was capable of completing only one type of instrument approach in Antarctica.
The commission recommended that the Chief of the Air Force reviewed the risk assessment for using the Boeing 757 aircraft for Antarctic flight operations.
The commission found the incident demonstrated how a properly trained crew was able to function effectively in demanding circumstances and make a safe landing.
The Air Force has carried out 650 flights to Antarctica since it began working with the Antarctic Programme in 1965.