Executive summary
On Monday 3 March 1997 at 1014 hours, Cessna 185F ZK-PRM became airborne from runway 16 at Wellington International Aerodrome, behind a Boeing 727 which had departed directly ahead. The Cessna encountered wake turbulence which caused the pilot to lose control of the aircraft at a height from which recovery was not possible. Neither of the two occupants was injured but the aircraft was substantially damaged. The pilot took-off from a mid-point runway position and had requested and been granted a waiver of the wake turbulence separation standards. The pilot misjudged the likely region of wake turbulence in his take-off path. The error resulted from a lapse in concentration, partly due to the routine nature of the flight and partly because of his preoccupation with his personal concerns. Safety issues discussed include the appropriateness of allowing waivers of the wake turbulence separation standards. Safety recommendations were made on the safety issues.
Related Recommendations
Publish another article on wing-tip vortices, in the Vector magazine, to alert pilots and operators to wake turbulence concerns. This article should highlight the dangers of encountering wake turbulence and explain how it can be avoided.
Ensure that waivers of the wake turbulence separation standards are: (i) restricted to VMC, by day only; and (ii) specifically acknowledged by pilots with words such as "ACCEPT WAIVER"; and (iii) not permitted under certain circumstances, for example: when a light aircraft: (a) will take-off behind a heavy or medium aircraft from a point on the runway more than 150 m beyond where the heavy or medium aircraft started its take-off roll; or