Aircraft and Registration
The aircraft involved was a Schweizer S 269C helicopter, registration I-GUAN.
Date and Location
The incident occurred on 27 May 2002 at 07:30 UTC near Caresana (VC), Italy.
Event Description
During an agricultural flight involving the spraying of substances for anti-larval treatment of rice fields, the pilot, while in translational flight at about 6 meters above ground, perceived strong vibrations from the tail rotor. As a precaution, he decided to perform an off-field landing. After touchdown, it was found that the tip of one tail rotor blade had ruptured.
Pilot Information
The pilot was a 30-year-old male of Italian nationality, holding a valid commercial helicopter pilot license and a valid medical certificate. He had a total of 628 flight hours, of which about 616 on type. In the last 24 hours, he had flown 0 hours; in the last 7 days, 18 hours 40 minutes; in the last 30 days, 38 hours 43 minutes.
Aircraft Information
The Schweizer S 269C is a single-engine helicopter with a maximum takeoff weight of 930 kg. It has a length of 9.40 m, a height of 2.66 m, and a main rotor diameter of 8.18 m.
Meteorological Information
Visibility was greater than 10 km, no wind, and 6/8 cloud cover.
Analysis
Examination of the tail rotor blade indicated that the tip failure likely resulted from the detachment of the resin fillets securing the basal tip during operation. This material, flung outward by centrifugal force, would have caused the rupture of the tip cap. The breakage and partial detachment of paint along the entire trailing edge and partial laminate failure indicated that the blade had undergone significant deformation, predominantly elastic, due to a strong stress applied in a rear-to-front direction. This stress was probably caused by an impact. The investigation did not find evidence to determine whether the impact occurred before or after the resin fillet detachment.
Probable Cause
The cause of the detachment of the blade tip was attributed to a technical factor, likely due to a strong stress.