Introduction
On 28 April 2021, at approximately 1315 hrs, a Hawker Sea Fury T Mk 20, registration G-RNHF, was destroyed when it struck the ground about 0.5 nautical miles from Runway 04 at RNAS Yeovilton, Somerset. The aircraft was on a private training flight with a crew of one pilot and one passenger. The pilot, aged 60, held an Airline Transport Pilot’s Licence and had 11,550 total flying hours, including 36 on type. The passenger sustained minor injuries; the pilot was uninjured.
History of the Flight
The aircraft was prepared for a training flight with the front seat pilot and a non-rated pilot in the rear seat for familiarisation. After a comprehensive brief, the crew started the engine using external electrical power. The engine started smoothly, with oil pressure initially indicating 110 psi while cold. During engine run-up checks, the pilot noted an excessive rpm drop on one magneto but after adjusting the throttle friction, the drops were within limits. Oil pressure was steady at 100 psi at 2,000 rpm. The pilot inadvertently omitted the supercharger gear change check but later completed it.
At 1300 hrs, the pilot began taxiing. During the pre-takeoff checks, at around 600 rpm, oil pressure dropped to about 60 psi, which was outside normal limits. Increasing power to 1,200 rpm restored the pressure. The pilot attributed this to higher oil temperature from the earlier engine run. The aircraft took off at 1309 hrs and turned northwest. Seeing weather ahead, the pilot turned east. Shortly afterward, low oil pressure was noted. The pilot made a PAN PAN call and turned back toward the airfield. The engine ran roughly, and after lowering gear and flap, the engine failed with violent thumps and seized. The pilot was unable to feather the propeller, and the increased drag prevented reaching the runway. A MAYDAY call was made. The aircraft struck the ground about 0.6 nm from the runway threshold.
Accident Site and Wreckage
The aircraft first struck a telegraph pole, clearing a nearby house by about 6 m, then struck the ground in a level attitude in a paddock. Ground marks indicated the right main landing gear and tailwheel were extended; the right mainwheel separated and the leg folded rearward. The left main gear was found retracted. The aircraft slid 95 m before striking a hedge and earth berm, causing the wing and engine to separate from the fuselage. The fuselage came to rest inverted, covered in light oil. No fire occurred. The propeller was in fine pitch with all blades folded rearward.
Engine Examination
The Centaurus XVIII engine had extensive damage in the rear crankcase due to overheating of the rear crankpin bearing. The bearing was a steel sleeve coated with a tin-based white metal alloy. Oil was supplied through drillings in the hollow crankshaft. The cause of the bearing overheating could not be determined due to the severe damage.
Conclusion
The aircraft was destroyed, but both occupants were able to exit the cockpit without assistance. The engine seizure resulted from rear crankpin bearing overheating, the root cause of which was not established.