EASA AD US-2019-13-05
Fuselage - Main Transmission Forward and Aft Frame Assemblies and Adjacent Skins - Inspections
Summary
Federal Aviation Administration Airworthiness Directive 2019-13-05 is a final rule addressing certain Sikorsky Aircraft Corporation Model S-92A helicopters. It mandates inspections of the main transmission forward and aft frame assemblies and adjacent skins for cracks and loose fasteners, and establishes life limits for specific frame assemblies to ensure continued airworthiness.
What Changed
This new airworthiness directive introduces mandatory inspections prompted by fatigue analysis and the discovery of a crack in the STA 362 frame and skin. It requires operators to inspect for cracks and loose fasteners, repair or replace affected parts, and adhere to updated life limits for frame assemblies. The directive also revises previously proposed life limit hours to longer, FAA-approved intervals and removes daily inspection requirements.
Why It Matters
This directive is critical for aviation professionals as it addresses a potential unsafe condition that could lead to main transmission frame failure and loss of helicopter control. Compliance ensures the structural integrity of key airframe components, thereby enhancing flight safety and reducing the risk of in-service failures. Maintenance and compliance teams must update their inspection and replacement schedules accordingly to meet regulatory requirements.
What To Do
Operators of Sikorsky Model S-92A helicopters must perform inspections of the main transmission forward and aft frame assemblies and adjacent skins for cracks and loose fasteners as specified. Any cracked or loose parts must be repaired or replaced, and life limits for certain frame assemblies must be established and followed. These actions are effective starting August 29, 2019.
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