Airworthiness Directive · Amendment 39-19586 · Main rotor blade
MD Helicopters, Inc. (MDHI), Helicopters
This AD applies to MD Helicopters, Inc., Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, certificated in any category, with a main rotor blade (MRB) part number 369A1100, 369D21100, 369D21102, 369D21120, 369D21121, 369D21123, 500P2100, or 500P2300, all dash numbers, installed.
We are adopting a new airworthiness directive (AD) for MDHI Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This AD requires inspecting each main rotor blade (MRB) for a crack. This AD was prompted by reports of cracked MRBs. The actions of this AD are intended to address an unsafe condition on these helicopters.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 25 hours time-in-service, and thereafter at each 100-hour inspection or annual inspection, whichever occurs first:
(1) Using a 10X or higher power magnifying glass and a light, inspect each MRB trim tab end at the trailing edge corner where the trim tab and MRB meet for a crack. If there is a crack, before further flight, replace the MRB.
(2) Using a 10X or higher power magnifying glass and a light, inspect the top and bottom surface of each MRB adjacent to the inboard trim tab corner for a crack, from the trailing edge towards the leading edge. If there is a crack, before further flight, replace the MRB.
