There was a low likelihood of the weather conditions at Pegasus Field aerodrome deteriorating below minima after an aeroplane passed the point of safe return. However, the potential consequences of that happening were elevated for the Boeing 757 aircraft because of the lack of alternative approach paths and aerodromes suitable for this aircraft type.
There are five factors that were not considered, or only partly considered, but should have been when assessing the risk of using the Boeing 757 aircraft for Antarctica operations:
- the weather criteria for an aeroplane passing the point of safe return should consider the presence of low cloud and fog below the main cloud base as a limiting factor
- there is an increased likelihood of weather conditions deteriorating below minima early in the summer season
- the accuracy of instrument approaches should be treated with caution prior to calibration flights being conducted early in the summer season
- the RNZAF aircraft is capable of completing one type of instrument approach only in Antarctica - a GPS approach
- the lack of suitable diversion airfields and the consequences of a whiteout landing.
The Commission recommends that the Chief of Air Force review the risk assessment for using the Boeing 757 aircraft for Antarctic flight operations, taking into account these matters and any other matters not considered during the initial risk assessment.