An automatic warning, "Don't sink, don't sink", sounded in the cockpit as Pacific Blue Flight 89 took off from Queenstown Airport on June 22, 2010, the Queenstown District Court heard yesterday.
An Air New Zealand pilot of 39 years, Colin Glasgow, now retired, told the court the pilot flying 71 passengers to Sydney received warnings no pilot should hear in their career.
"Pilots will fly their entire career and not hear these warnings," the prosecution witness said.
On trial is a 54-year-old Auckland pilot, who has denied a charge of operating a plane carelessly. His name is suppressed.
Mr Glasgow told the court, in his opinion "a number of elements" were breached in this flight that placed the aircraft at undue risk.
The pilot's intention to place the plane on an automatic pilot system would not have worked because the plane was not in stable condition, he said.
"Queenstown is known for severe turbulence. The existence of crosswinds cannot have been a surprise for the defendant."
Shortly after the plane took off, the pilot was warned by the first officer regarding his speed. Also triggered was an automatic warning from the cockpit - "Don't sink, don't sink" - as the pilot descended slightly to avoid clouds blocking visibility.
The Civil Aviation Authority had alleged the defendant left the airport at 5.25pm, breaching the airline's rule that flights could only leave at a minimum of 30 minutes before the evening civil twilight (ECT) time of 5.45pm.
"The point is, the defendant was aware he was to depart 30 minutes before ECT.
"The defendant took off within ECT. This in itself was unsafe," Mr Glasgow said.
The plane took off at 5.25pm, which the expert witness said "effectively took away the procedure that would save them" [the plane occupants] if an engine failure had occurred.
One flight had been cancelled before the Pacific Blue flight because of the conditions.
"While aviation will always involve risk, pilots will endeavour to minimise risk, even if it means holding a flight."
Mr Glasgow said the first part of any flying procedure out of Queenstown required the pilot to see visually before instrument flight rules (IFR) were implemented.
The late take-off would have affected the pilot's visibility within the "visual segment" before the plane had reached its reference point (between Deer Park Heights and the Remarkables) which is effectively when IFR could begin.
"The first part of the procedure must be flown where the pilot can actually see."
He said it was "probable" the plane had flown within a cloud barrier - a required distance of 2km vertical and 500m horizontal.
"In my opinion, there are a number of elements breached at this flight that placed the aircraft at undue risk.
"If the defendant managed to avoid cloud, this was sheer luck."
Mr Glasgow told the court the defendant had committed a "highly unusual and dangerous operation" in which he exceeded a speed limit of 180 knots as well as cutting a corner at Slopehill.
"Aviation safety is reliant on rules.
"They are not guides or pointers but protocol and procedures to be followed by the letter," he said.
"Strict compliance with rules is the best way to ensure the safety of the plane and its passengers.
"The pilot is not free to choose what alternate route to take."
Queenstown Airport was one of the most technical for pilots to fly in and out of because ofsurrounding mountains and valleys, and its narrow runway.
This meant pilots using the airport were required to undergo "special training" to adhere to the "restrictions and controls" as a category X airport (the highest of the four-level system).
"It is an airport that commands respect and discipline to ensure safety."
