What happened
On 15 September 2009, a Grob G115E Tutor, registration G-BYXD, was conducting a training flight at Boscombe Down, Wiltshire. The flight, operated by a University Air Squadron, was intended to include a practice forced landing exercise. Although the forecast indicated winds of 20 kt from 010° with gusts up and to 26 kt, the actual wind conditions were reported to be approximately 5 kt higher than predicted.
During the landing on Runway 35, the student pilot followed the standard pattern. As the aircraft approached the runway, the instructor advised the student to lower the nose to maintain a target airspeed of 75 kt. While the student performed a final speed check just below 100 ft and transitioned into the flare, the aircraft experienced a sudden, sharp increase in the rate of descent. This caused the aircraft to strike the runway surface with significant force. The instructor took control of the aircraft following the initial impact and landed the aircraft after a subsequent bounce. The aircraft was then brought to a stop on a grass area beyond the runway end.
The investigation
The investigation examined the damage sustained by the aircraft, which included impacts to the main and nose landing gear, a cracked engine mounting frame, and damage to the firewall near the nose leg attachment point. Investigators reviewed the flight data and found that the on-board meter recorded a peak normal load factor of 6.5g during the landing event. The investigation also looked into the loss of braking and nosewheel steering functionality following the touchdown, which likely resulted from the severity of the impact.
Findings
- The aircraft experienced a sudden increase in the rate of descent during the flare phase of the landing.
- The instructor suggested that wind shear was the probable cause of the sudden descent rate increase.
- The landing resulted in no injuries to the two crew members on board.