AD 99-09-05 Amendment 39-11137

This amendment adopts a new airworthiness directive (AD) that is applicable to BHTC Model 230 helicopters. This action requires initial and repetitive visual inspections and verification of the torque of the bolts on the main rotor hub. This amendment is prompted by a report of fatigue cracks around the bolt holes of the main rotor pitch horn (pitch horn) and a cracked main rotor flapping bearing assembly (flapping bearing assembly) on a similar model helicopter. This condition, if not corrected, could result in fretting-induced fatigue cracking of the flapping bearing assembly and around the bolt holes of the pitch horn, loss of the rotor system, and subsequent loss of control of the helicopter.