What happened
On 23 August 2013, a Yak-52, registration G-STNR, was performing a private flight inbound to Swansea Airport. During the process of an expedited approach, the pilot attempted to configure the aircraft for landing by selecting both the landing gear and the flaps.
As these systems were deployed simultaneously, the sudden demand placed on the aircraft's pneumatic system prevented the landing gear from fully extending and locking into position. Consequently, the aircraft made contact with the runway on its fuselage and trailing edge of the flaps. The impact caused damage to the propeller, flaps, and tailskid.
The investigation
Following the incident, the aircraft was recovered using slings. During this process, the three gear legs were observed to lower and subsequently lock into their proper positions.
Subsequent inspections of the aircraft's systems revealed that a small washer and various metallic particles had been trapped within the oil chip detector filter.