What happened
On 14 September 2014, a Skyranger Swift 912S, registration G-CFIA, was performing a private flight at Brookfield Farm Airfield in Lincolnshire. During the landing phase, the aircraft had decelerated to approximately 20 knots when it encountered an uneven section of the grass runway. Following this bump, the aircraft suddenly veered toward the right, leaving the runway and moving into an adjacent cultivated field.
As the aircraft departed the runway, it pitched forward and to the left. This movement resulted in the propeller and the left wing striking the ground. There were no injuries to the pilot or the single passenger on board, though the aircraft sustained significant damage to the engine cowlings, propeller, engine, nosewheel, left landing gear, and left wing.
The investigation
Investigators examined the sequence of events following the excursion. The pilot reported that the aircraft's left wheel had entered a rut or hole in the grass surface. This impact caused the left landing gear spoke to break free and rotate forward over the wheel. This mechanical failure had the direct consequence of making the left brake non-functional.
Findings
- The primary cause of the excursion was the failure of the left brake due to the structural displacement of the landing gear spoke.
- The loss of the left brake meant that only the right brake remained effective when the pilot attempted to decelerate.
- The resulting asymmetrical braking force caused the aircraft to veer sharply to the right, leading to the runway departure.