You could be forgiven for developing a fear of flying in and out of the Wakatipu after sitting in Queenstown District Court these past two weeks.
During a defended hearing for a Pacific Blue pilot accused of operating an aircraft in a careless manner, details have emerged about the challenges of Queenstown Airport that pilots face on a daily basis.
Retired Civil Aviation Authority inspector and pilot Colin Glasgow, an expert witness in the case, told the court that it has a “Category X” rating in CAA and airline operator circles – the highest rating according to degrees of difficulty.
“It is an airport which commands respect and commands discipline by all concerned to ensure it remains safe and incident free,” he told the court on Monday.
On the good days – and there are many – Queenstown is fabulous to fly in to. It’s even been voted by travellers as the seventh-best airport arrival in the world.
But conditions can change rapidly, and it can be very difficult for aviation when the weather’s bad, Glasgow explains.
Because the aerodrome is situated at the confluence of three mountain valleys, it can be subject to strong, gusty and variable winds.
Departing either towards the Kawarau Valley or up Frankton Arm, aircraft must achieve certain climb rate altitudes throughout their departure procedure so they can fly over the mountains and away.
And being among the mountains brings added issues with air pressure, Glasgow says.
Most airfields in New Zealand are at sea level, whereas Queenstown’s is 357 metres – 1171 feet – above mean sea level.
“At 1200ft the air level is affected by a low of air pressure which in turn reduces the take-off and landing performance of aircraft. Aircraft do not perform as well in the Queenstown environment as compared to sea level airports,” he says.
Mountains also prevent the use of radar in the local airport’s air traffic control tower.
“This means the air traffic control cannot see on the radar other aircraft in the area which may be obscured from the tower by the terrain or bad weather,” Glasgow adds.
“For this reason Queenstown Airport is in Class D airspace. This is a CAA-defined airspace around the airport where aircraft have to visually avoid each other because the aircraft cannot be seen on the radar.
“This means [pilots] have to maintain visual contact with the ground and comply with the visual flight rules …”
Queenstown Airport’s runway is narrower and shorter than normal. It’s 30m wide, compared to the usual 45m width, and less than 1800m long.
This presents a danger for “runway excursions” – when the aircraft veers off the runway caused by strong cross-winds – and can also cause an optical illusion for the pilot during landing, Glasgow says.
“This means that aircraft cannot operate into the airport with any malfunctions in braking or steering systems.”
It’s because of all these issues that Queenstown has been given the Category X rating. As a result, commercial airline pilots must have the most amount of training available when flying in to the resort.
The rating is the most severe of a four-tier system. Category A airports like Christchurch or Auckland have no unusual features, Category B airports have “sufficiently unusual” features, and Category C airports, like Dunedin and Wellington, have “sufficiently difficult or unusual features which require a special briefing”.
“Queenstown, as a Category X airport, has more numerous and significant considerations,” Glasgow says.
Another major challenge is the aerodrome’s large amount of general aviation activity.
The court has heard that Queenstown is the second-busiest airfield in New Zealand, and it’s common knowledge that it’s the second-fastest growing airport in Australasia. It is this month preparing to celebrate the arrival of its one millionth passenger for the first time in a calendar year.
Glasgow: “The more aircraft in the air, the greater the need to ensure those aircraft do not collide with each other.”