Summary
This document revises an earlier proposed airworthiness directive (AD), which would have superseded an existing AD that is applicable to all British Aerospace Model ATP airplanes. The existing AD currently requires inspections to detect cracking of the aft end of the wing rib boom angles on the left and right engine, and repair or replacement of the wing rib boom angle assemblies, if necessary. The existing AD was prompted by the detection of cracks in the engine outboard rib boom angles at the main landing gear (MLG) actuator attachment point. Its required actions are intended to prevent structural failure of the actuator attachment point, which could lead to collapse of the MLG. The previously proposed action would have limited the applicability of the rule to certain airplanes; revised the initial inspection threshold for certain modified airplanes; and would have required that modified boom angles be installed whenever replacement is necessary. This action revises the proposed rule by correcting the actions necessary to be accomplished for one specific type of cracking condition.