On 4 July 1966, an Air New Zealand Douglas DC-8-52 crashed on takeoff from Auckland International Airport on a training flight, killing 2 out of the 5 crew members on board.

The other two crew members of the flight were Captain Bernard Wyatt and First Officer Kenneth Sawyer, who had no official flying duties.

The aircraft rolled sharply to the right, and the first officer, who was the pilot flying, was unable to maintain directional control even when applying a full left rudder.

Instead of using the aforementioned technique to reduce power on the engine, he used the spoiler disarm extension, a rod attached to the number four thrust lever.

[5] The flight crew started up the aircraft engines at 15:50 NZST and four minutes later, air traffic control cleared ZK-NZB to the holding position at the threshold of runway 23.

After VR, he described that the drag on the right side of the aircraft was so severe that he thought that Captain McLachlan simulated the failure on engine number three and four.

[5] The investigation board interviewed twelve witnesses to the crash, eleven employees of Air New Zealand and one executive officer of a different airline.

Most witnesses reported that the takeoff appeared normal, the rotation being steeper than usual, the right wing moving downward, and the aircraft never reaching more than 100 ft (30 m).

To do this, the investigation used an Air New Zealand DC-8 aircraft that would replicate the path of the test flight, activating the reverse thrust when and where the witnesses said it was on ZK-NZB.

Using a parked DC-8, investigators replicated Captain McLachlan's technique and found that at sufficient speeds, the inertia force created by the movement could cause the thrust brake lever to enter the reverse detent.

Based on the evidence, the investigation determined that the captain inadvertently activated the reverse thrust on the number four engine, noticed the problem, but deactivated it too late to recover the aircraft.

However, with an activated thrust reverser on the number four engine, Vmca was 141 kn (261 km/h; 162 mph), which only increased with reduced controls.

That condition arose when very rapid rearward movement of the power level generated an inertia force which caused the associated thrust brake lever to rise and enter the reverse idle detent.

After lift-off, the minimum control speed essentially required to overcome the prevailing state of thrust imbalance was never attained and an uncontrollable roll, accompanied by some degree of yaw and sideslip in the same direction, ensued.

When the condition of reverse thrust was recognised and eliminated, insufficient time and height were available to allow the aircraft to recover from its precarious attitude before it struck the ground.

The report summarized the problem that resulted in the crash by saying: For it is a well-recognised fact that if a particular thing can be done, albeit quite unintentionally, then sooner or later some person will do it.

[5]: 29 Within three hours after it was discovered that a fast movement to idle power could cause a reverse thrust deployment, the AIB notified the Douglas Aircraft Company of the flaw, who later sent out notices to all DC-8 operators and pilots of the risk.

In the final report, the AIB called for a mechanical intervention to stop the deployment of reverse thrust in the circumstances that led to the accident, although it makes no mention as to whether this was followed through.