What happened
On 24 November 2017, a Titan T-51B Mustang, registration G-CIXK, was performing a private flight from Shacklewell Airfield in Lincolnshire. During the takeoff roll, after the tailwheel had transitioned into the airborne position, the aircraft began to swing toward the left side of the runway. The pilot attempted to counteract this movement using right rudder, but the control input was ineffective.
As the aircraft approached a fence and hedge located in an adjacent field, the pilot determined there was inadequate space to abort the takeoff. In an attempt to avoid the obstacle, the pilot tried to lift the aircraft off the ground to clear the hedge. However, the main landing gear made contact with the vegetation, causing the aircraft to depart the runway and come to rest in a nearby field with the nose and left wing on the ground. There were no injuries to the pilot, though the aircraft sustained damage beyond economic repair.
The investigation
Investigators examined the aircraft and the runway surface to determine the cause of the directional instability. Analysis of tyre marks left on the grass runway showed that the tracks on the left side were deeper than those on the right. This indicated that the ground on the left side of the 15-meter-wide runway was wetter and softer than the right side.
Further investigation into the pilot's actions revealed that the pilot had landed further down the runway earlier that day, where the ground had been firmer. The pilot noted that the increased drag caused by the soft, wet ground on the left side of the runway likely exceeded the available rudder authority during the takeoff roll. The pilot also acknowledged that a pre-departure inspection of the runway threshold might have identified the soft ground, potentially allowing for a takeoff along the firmer right side of the runway.