What happened
On 10 March 2015, a Kolb Twinstar MkIII, registration G-MZGJ, was conducting a private flight departing from Runway 25 at Otherton Airfield, Staffordshire. Shortly after takeoff, while performing a shallow left turn at an altitude of roughly 450 ft, the pilot experienced a restriction in pitch control. This limitation prevented the aircraft from maintaining its altitude, forcing the pilot to execute an emergency landing.
During the final stages of the forced landing approach, the aircraft's left wheel made contact with a wooden post. This impact caused the aircraft to yaw sharply to the left, resulting in the left landing gear digging into the ground. The aircraft then slewed across the terrain for about 15 metres before coming to a halt. There were no injuries to the pilot or the single passenger on board.
The investigation
The investigation, supported by findings from the Light Aircraft Association (LAA), focused on the sudden loss of pitch control. Although the pilot had conducted control checks prior to departure that showed no issues, the restriction was present during the flight but notably absent following the landing.
Technical examination of the Kolb Twinstar MkIII suggested that the control restriction was likely due to excessive slack in the elevator control cables. This slack allowed the cables to make contact with the tail boom. Investigators also considered that the pilot's bulky clothing might have played a role by pushing a turnbuckle against the side of the boom, creating a temporary mechanical interference.
Findings
- The primary cause of the control restriction was excessive slack in the elevator control cables, which allowed them to contact the tail boom.
- The clothing worn by the pilot may have contributed to the incident by displacing a turnbuckle into the boom.
- The aircraft sustained significant damage, including a buckled airframe, damage to the left landing gear, a cracked nose cone, and internal damage to the left wing structure.