What happened
On 7 October 2013, a Royal New and Zealand Air Force Boeing 757 departed Christchurch, bound for Pegasus Field in Antarctica. The flight carried 117 passengers, including government officials and Antarctic program staff, along with 13 crew members. Due to the aircraft's limited fuel capacity, a return trip to Christchurch without refueling at Pegasus Field was not possible, necessitating a pre-calculated point of safe return.
While the crew initially received weather updates suggesting conditions would improve, a fog bank eventually enveloped the Pegasus Field runway. Having already passed the point of safe return, the crew was committed to landing at the only available airfield. After an initial failed attempt and a period of holding, the crew attempted a second approach using a descent altitude below published minimums. Following a missed approach, a third attempt was made. Despite the near-whiteout conditions, the crew identified the runway markings at approximately 110 feet and completed a successful landing. There were no injuries and no damage to the aircraft.
The investigation
The investigation examined the decision-making process regarding the point of safe return and the subsequent approach procedures. Investigators reviewed the weather observations provided by various international agencies and assessed the crew's use of descent altitudes below standard minima. The inquiry also scrutinized the broader risk assessment used to determine the suitability of the Boeing 757 for Antarctic operations.
Findings
While the investigation concluded that the crew's decision to proceed past the point of safe return met established criteria and that their actions during the low-visibility approach were appropriate given the lack of alternatives, several systemic failures were identified. The primary finding was that the risk assessment for using this aircraft type in Antarctica was inadequate. Specifically, the assessment failed to account for:
- The high-risk nature of using an aircraft with limited alternative approach options and no secondary aerodromes.
- The need to consider low-level fog and cloud as a critical limiting factor when determining the point of safe return.
- The increased probability of weather degradation during the early summer season.
- The potential for reduced accuracy in instrument approaches before seasonal re-calibration flights are completed.
- The limitation that the Royal New Zealand Air Force Boeing 757 is restricted to only one type of instrument approach in the region.
Safety action
The Commission recommended that the Chief of Air Force conduct a comprehensive review of the risk assessment protocols for Antarctic Boeing 757 operations, ensuring that the identified environmental and operational limitations are integrated into future planning.