What happened
On the morning of 3 March 1997, a Cessna 185F, registration ZK-PRM, departed from runway 16 at Wellington International Aerodrome. The aircraft's takeoff occurred shortly after a Boeing 727 had departed from the same runway, positioned directly in the path of the smaller aircraft.
As the Cessna 185F climbed, it encountered the wake turbulence generated by the preceding heavy jet. This encounter caused the pilot to lose control of the aircraft at an altitude too low to allow for a successful recovery. While the aircraft suffered substantial damage, there were no injuries to the two occupants on board.
The investigation
Investigators determined that the pilot had departed from a mid-point position on the runway. Prior to takeoff, the pilot had requested and received permission to bypass standard wake turbulence separation requirements. The investigation focused on the pilot's positioning and the decision-making process regarding the separation waiver.
Findings
Technical analysis established that the pilot misjudged the location of the wake turbulence along the takeoff path. This error was attributed to a lapse in concentration, which was influenced by two primary factors: the routine nature of the flight and the pilot's preoccupation with personal matters.
Safety action
Following the investigation, safety issues were raised regarding the practice of granting waivers for wake turbulence separation standards. Specific safety recommendations were issued to address these concerns.