EASA Regulations for Textron Aviation 421C

Wings - Lower Forward Carry Through Spar Cap - Inspection / Replacement

The Federal Aviation Administration's Airworthiness Directive 2018-03-03 R1 revises the original AD 2018-03-03 for certain Textron Aviation Inc. Models 401, 401A, 401B, 402, 402A, 402B, 402C, 411, 411A, 414, 414A, 421, 421A, 421B, 421C, and 425 airplanes. This directive addresses the inspection and replacement of the left and right forward lower carry through spar caps to detect and correct cracks caused by metal fatigue. The AD aims to prevent potential failure of the spar cap during flight, which could lead to loss of control.