Executive summary
On Wednesday 10 August 2005, at about 0845, ZK-WWH, a Cessna U206G, took off from Queenstown Aerodrome for Mount Cook Aerodrome with a pilot and 5 passengers on board. Just after take-off, the pilot encountered control difficulties that culminated in the aircraft striking the runway with its left wing tip and failing to remain airborne. The aircraft was substantially damaged, but no one was injured.
Although the pilot had taken action to remove frost from the aircraft, a layer of frost remained on the wing upper surfaces for the take-off. It was possible that wake turbulence from a preceding Cessna 206 initially upset ZK-WWH, but the frost on the wings was considered to be the main reason for the loss of control. In addition, the centre of gravity position was probably aft of the rear limit for take-off.
Safety issues identified included:
• the need to ensure critical aircraft surfaces are completely free of contaminants, such as frost, before flight
• pilots’ awareness of wake turbulence and the need to report severe wake turbulence encounters
• the specification of all relevant conditions in weight and balance calculations
• the accuracy of safety briefing information provided to passengers
• the proper restraint of baggage and cargo.
Safety recommendations were made to the operator and to the Director of Civil Aviation, as appropriate, to address these issues.
Related Recommendations
revise the educational material on wake turbulence to include guidance for operations at uncontrolled aerodromes, and to emphasise that pilots should observe the ICAO recommended minimum separation distance between light aircraft and report any severe wake turbulence incidents.
Amend the Cessna 206 passenger safety information cards to show accurately how to operate the cargo doors and exit the aircraft, including when the flaps are extended.
Revise the GAP booklet "Winter Flying" to emphasise that hard ice will not be removed by brushing.
Instruct his pilots to perform a tactile check before take-off, when conditions dictate, to ensure that critical surfaces are free of contaminants such as frost and ice.
Amend his standard load plans to specify the baggage or cargo conditions that must be met if pilots are to rely on the plans to keep the centre of gravity within limits.