Main Rotor System - Hub Lead-lag Bolts - Removal
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of the affected MD Helicopters models must identify and remove from service any main rotor hub lead-lag bolts with the specified part number 369D21220 and listed serial numbers within three months of June 30, 2020, or at the next main rotor overhaul, whichever is sooner. They must not install any affected bolts after this date. Coordination with MD Helicopters for replacement scheduling and adherence to the service bulletins is required.
Summary
The Federal Aviation Administration's Airworthiness Directive 2020-11-07 addresses MD Helicopters Inc. models 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N. It mandates the removal from service of certain main rotor hub lead-lag bolts, part number 369D21220, that have non-conforming serial numbers due to unauthorized cadmium plating repairs. This directive aims to ensure continued airworthiness and safety of these helicopter models.
What changed
This new airworthiness directive requires operators to remove affected bolts from service within three months or at the next main rotor assembly overhaul, whichever occurs first. It prohibits the installation of any bolts with the specified part and serial numbers after the effective date. The directive also updates labor hour estimates for compliance to include removal of the main rotor blades, driveshaft, and head.
Why it matters
This directive is critical for aviation professionals as it addresses a safety risk from bolts with reduced fatigue life that could lead to main rotor blade loss and loss of helicopter control. Operators and maintenance organizations must ensure timely bolt replacement to maintain compliance and prevent potential accidents. Accurate labor and cost estimates help maintenance planners allocate resources effectively.
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