At 15:50 the engines of DC-8 ZK-NZB were started in preparation for a routine crew training flight within the Auckland terminal zone, which was scheduled to last two hours. The aircraft taxied to runway 23 for departure. At 15:59 the flight was cleared for takeoff when ready. The aircraft made an apparently normal takeoff roll. Rotation appeared more rapidly achieved and steeper than usual and the aircraft’s tail passed unusually close to the runway surface. Almost immediately, the starboard wing dropped and the aircraft began turning to starboard while still in a nose-up attitude. The aircraft lost height by sideslipping inward and the starboard wing tip then struck a grassed area close to the edge of the runway. The aircraft pivoted about its nose at a fuselage-to-ground angle of about 50 degrees. Fire broke out in the vicinity of the starboard wing root and the aircraft rapidly began to disintegrate. Following nose impact, the entire flight deck section broke loose and eventually came to rest inverted. PROBABLE CAUSE: “The incurrance of reverse thrust during simulated failure of no. 4 engine on takeoff. 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.”