AD 97-15-16 Amendment 39-10152

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 97-15-16, which was sent previously to all known U.S. owners and operators of BHTC Model 430 helicopters by individual letters. This AD requires inspections of all 4 main rotor adapter assemblies for evidence of flapping contact between the adapter liners and the upper stop assembly plugs, and for evidence of lead-lag contact between the adapter pads and the yoke assembly; installing a never-exceed-velocity (VNE) placard; marking the airspeed indicator to reflect the airspeed restriction; installing a slippage mark on the airspeed indicator glass and instrument case; and inserting revisions to the rotorcraft flight manual to reflect the airspeed revision. This amendment is prompted by a report of a main rotor tip path plane separation, which occurred during a ferry flight at an airspeed of more than 140 knots indicated airspeed (KIAS). The actions specified by this AD are intended to prevent tip path plane separation, increased vibrations, possible damage to the main rotor system, and subsequent loss of control of the helicopter.