AOPA Turbine Pilot Magazine - June 2018 - 20

WAYPOINTS

Watching the magic box

BY THOMAS B. HAINES
Editor in Chief

Catbird seat to one of the most complicated
approaches on Earth
THE ELEVATED JUMPSEAT in the center of the wide
Airbus A320 cockpit gave me a commanding view of
the flight deck. Feeling like Star Trek's Captain Picard,
I wanted to point my finger and say, "Make it so!" as we
began the complicated instrument approach procedure
to Runway 23 at Queenstown, New Zealand. I wasn't
sure whether the Kiwi pilots would get the Yankee reference, so I sat quietly mesmerized as the airplane began
its descent from 10,000 feet to 8,700 feet and then followed a curved path down to 7,600 feet at the next fix.
Ultimately, the procedure would descend us through a
series of valleys down to the airport on the shore of Lake
Wakatipu at an elevation of 1,171 feet. All the while, the
autothrottles worked hard to manage the speed.
The approach, one of the most complicated in the
world, looks like a question mark lying on its side-
or at least it
does when you
start at the initial approach
fix we used
on the flight
from Auckland.
The minimum
safe altitude
within 15 miles
is 10,000 feet;
within 25 miles
A SECTION of the New Zealand Civil Aviation Authority
it is 11,400 feet.
approach plate shows the question mark approach.
In other words,
there's a lot of brown terrain shading on the approach
procedure, and the terrain depiction on the Airbus navigation display was a glimmering mass of green, brown,
and yellow.
Air New Zealand Capt. Perry Earwaker and First
Officer Scotty Vincent briefed the approach carefully
as we dodged rain showers over the southern portion
of the North Island. The pair is only one set of 20 flight
crews in the whole airline who are authorized to fly
the approach at night, which requires use of the headup display. Even during the day, the approach requires
Editor in Chief
special training. Earwaker explained that the approach
TOM HAINES owns
is complicated not just by the terrain, but also by the
a 1972 Beechcraft
A36 Bonanza
shifting winds. Starting at 10,000 feet, the Airbus may
that is also capaenter the curved procedure with as much as a 120ble of flying RNP
knot tailwind while beginning a descent-go down and
approaches.

20 | AOPA PILOT June 2018

slow down. However, as the airplane descends into the
valleys, the tailwind may disappear or become a headwind as the flight path changes directions. Further
complicating are The Remarkables, a string of mountains on the edge of Queenstown that end just before
the lakeshore and at about the time the Airbus swings
around a corner to set up for the final segment. There,
at about the time the crews click off the autopilot,
the winds often shift from a headwind to perhaps a
30-knot crosswind-or maybe a tailwind. All this while
trying to line up with a runway that is less than 6,300
feet long-not very long for an airliner. So you better
have the speed nailed.
Although most airline operations require a stabilized
straight-in approach from miles out, Queenstown has
the lowest runway alignment of any Required Navigation
Performance (RNP) approach in the world, according to
Graham Cheal, manager of aircraft operations and airline technical support for Air New Zealand. He provided
an in-depth briefing about how the approach was developed to attendees at the International Council of Aircraft
Owner and Pilot Associations' biennial World Assembly
held in Queenstown in March. An Air New Zealand
Airbus can be as low as 400 feet above the ground-in
the clouds-before it is fully aligned with the runway,
with towering terrain all around. The missed approach
procedure is almost as complicated, requiring a maximum-effort climb and a curved path down the lake.
As if that isn't sporting enough, the GPS-calculated
flight path can move left or right as much as 100
meters throughout the day, depending on atmospheric
conditions.
The current version of this RNP approach, first used in
2016, was years in development and provides minimums
hundreds of feet lower than earlier RNAV approaches.
The airline brought in a human factors expert to develop
training procedures for the approach and to help pilots
transition from flight director guidance to visual guidance in the final seconds of the procedure. As recently as
2008, experts had concluded that night minimums as low
as those flown today were simply too dangerous.
Fortunately on the day of my flight, skies were clear
and I got to see the magic box do its thing without a
cloud in sight; and what an amazing sight it is. AOPA
EMAIL thomas.haines@aopa.org

AOPA Turbine Pilot Magazine - June 2018

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