Airworthiness Directives; Aerospatiale Model ATR42-300 and ATR42- 320 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to all Aerospatiale Model ATR42-300 and ATR42-320 series airplanes, that currently requires repetitive ultrasonic inspections to detect fatigue cracks of the lower lugs of the barrel of the main landing gear (MLG); and replacement of cracked lower lugs with new or serviceable parts, and a follow-on inspection. This amendment expands the applicability of the existing AD. This action also provides for an optional terminating action, which, if accomplished, terminates the repetitive inspection requirement. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to detect and correct fatigue cracking of the lower lugs of the barrel of the MLG, which could lead to the collapse of the MLG.