EASA AD US-2019-05-04
Main Rotor - Blades - Inspection
Summary
Federal Register Volume 84, Number 49 (March 13, 2019) Final Rule titled 'Main Rotor - Blades - Inspection' issues a new airworthiness directive (AD 2019-05-04) for MD Helicopters, Inc. models 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N. The AD mandates inspections of specific main rotor blades (MRBs) for cracks to address safety concerns. It applies to helicopters equipped with Helicopter Technology Company, LLC MRB part numbers 369A1100, 369D21100, 369D21102, 369D21120, 369D21121, 369D21123, 500P2100, or 500P2300.
What Changed
This new airworthiness directive introduces mandatory inspections of the MRB trim tab area for cracks using a 10X or higher magnifying glass and light. It requires initial inspection within 25 hours time-in-service and repetitive inspections at every 100-hour or annual inspection thereafter. The AD also requires immediate replacement of any MRB found cracked before further flight.
Why It Matters
This AD is critical for aviation professionals because cracks in main rotor blades can lead to blade failure and loss of helicopter control, posing a significant safety risk. Operators and maintenance organizations must incorporate these inspections into their routine maintenance schedules to ensure continued airworthiness. Compliance helps prevent accidents and ensures regulatory adherence, protecting both personnel and equipment.
What To Do
Operators of affected MD Helicopters must inspect each main rotor blade trim tab area for cracks within 25 hours time-in-service after April 17, 2019, and continue inspections at every 100-hour or annual inspection. If any cracks are detected, the affected MRB must be replaced before further flight. Maintenance teams should use a 10X or higher magnifying glass and proper lighting to perform these inspections and follow the specified service bulletins for guidance.
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