S1/2006 Bell 206B, G-WLLY
The aircraft was engaged upon a standard pipeline inspection flight. During the flight the vertical fin detached from the aircraft striking the tail rotor, and the tail rotor and its gearbox were torn from their mountings. The aircraft crashed, with fatal injuries to the two persons on board. Examination of the fin supports revealed evidence of fatigue in fractures through and around all four attachment bolt holes. Corrosion was evident on some of the fracture surfaces. The fin supports are subject to visual inspections every 100 flying hours; however the cracks originated in an area that cannot be seen without removing the fin, which is not required. The Special Bulletin includes two Safety Recommendations. The first of these is addressed to the UK CAA and recommends, for Bell and Agusta-Bell 206 series helicopters on the UK register, a one-off visual inspection of the fin supports with the fin removed. The second recommends that Transport Canada (the State of Manufacture), the EASA and the FAA each consider introducing a similar inspection.
S1-2006 G-WLLY.pdf (290.30 kb)