What happened
On 21 June 2003, a Rans S6-ES Coyote II, registration G-MZMS, was performing a private flight from Popham Airfield in Hampshire. The aircraft departed from the grass Runway 08 following a standard takeoff roll. As the aircraft climbed to an altitude level with the surrounding woodland, the right wing dropped. In an effort to maintain control, the pilot lowered the nose and leveled the wings.
However, the aircraft had reached a point where a left turn was necessary to avoid a petrol station located on the eastern edge of the airfield. During this maneuver, the aircraft began to lose altitude. Despite the application of full engine power, the pilot was unable to maintain height. Realizing the aircraft was sinking, the pilot attempted an emergency landing on Runway 03. The aircraft subsequently struck the ground with significant force east of the runway, resulting in major disruption to the airframe. There were no fatalities and no injuries to the two occupants.
The investigation
The investigation examined the wind conditions at the time of the accident and the local airfield environment. While the pilot observed a light and variable wind via the windsock prior to takeoff, meteorological aftercasts indicated a south-easterly surface wind. The investigation noted that the airfield's anemometer was recording a south-westerly wind, suggesting a discrepancy between the surface indicators and the actual wind flow.
Investigators also reviewed the adequacy of obstacle warnings. Although Popham is an unlicensed airfield, flight guides for the area explicitly warn of trees up to 50 feet high along the aerodrome boundaries. The investigation focused on whether the wind encountered above the tree line created a tailwind component or turbulence that the aircraft's engine could not overcome.
Findings
- The aircraft's climb was interrupted by the need to perform a left turn to avoid an obstacle.
- The primary cause of the loss of altitude was likely a combination of the aircraft's low power-to-weight ratio and transient wind effects encountered when climbing above the tree line.
- While the pilot believed a significant downwind component caused the sink, the investigation suggested that any tailwind component resulting from the wind direction was likely minimal.