Federal Register #FAA20264666

FAA Proposes Airworthiness Directive for MD Helicopters Main Transmission Coupling Inspection and Replacement

The Federal Aviation Administration (FAA), under the Department of Transportation, is proposing a new airworthiness directive for MD Helicopters, LLC models 369D, 369E, 369F, 369FF, 369H, and 500N. - Affected OEM: MD Helicopters, LLC (MDHI) - The directive targets the main transmission drive shaft coupling (part number 369H5660) - Applies to helicopters with couplings serial numbers 85640001 through 85640308 - Requirements: - One-time visual inspection of the main transmission drive shaft coupling for cracks using bright light and 10X magnification - If cracks are found, the coupling must be replaced before further flight - If no cracks are found, replacement is required within 300 hours time-in-service after the directive's effective date - Approximately 568 helicopters in the U.S. registry are affected - The directive references MD Helicopters service bulletins SB369H264R1, SB369D230R1, SB369E130R1, SB369F121R1, and SB500N067R1 - No specific purchase quantities for replacement couplings are provided, as replacements are only required if cracks are found during inspection - The proposal aims to address unsafe conditions and ensure continued operational safety of the affected helicopter models

Description

The FAA proposes a new airworthiness directive for certain MD Helicopters, LLC models 369D, 369E, 369F, 369FF, 369H, and 500N. This directive is prompted by reports of mechanical damage to the main transmission drive shaft coupling. It requires a one-time visual inspection of the couplings for cracks and replacement if necessary to address unsafe conditions. Comments on the proposal are due by August 17, 2026.

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