Airworthiness Directive 2006-08-12
recurringAirworthiness Directives; MD Helicopters, Inc. Model 600N Helicopters
What this AD requires
This amendment supersedes an existing airworthiness directive (AD) for the MD Helicopters, Inc. (MDHI) Model 600N helicopters, that currently requires inspecting both upper tailboom attachment fittings, nut plates and both angles for a crack or thread damage, and repairing or replacing any cracked or damaged part. That AD also requires replacing the upper right tailboom attachment bolt with a new attachment bolt, and if the upper right attachment bolt is broken, replacing the three remaining attachment bolts with airworthy bolts. Adding a washer to each bolt and modifying both access covers is also required. Thereafter, inspecting the upper tailboom attachments and repairing or replacing any cracked part is required by that AD. That AD was prompted by the discovery of a cracked attachment bolt on a helicopter. This AD requires those same actions, plus installing additional inspection holes in the aft fuselage skin panels and inspecting the upper and lower tailboom attachment fittings, the upper longerons, and the angles and nut plates for cracks. It also requires, within a specified time, replacing the upper right tailboom attachment fitting, painting the inspection area, and replacing existing nut plates. Additionally, it requires inspecting the attachment bolts for any damage or wear. This amendment is prompted by an accident involving a Model 600N helicopter. The actions specified by this AD are intended to prevent failure of the tailboom attachment fittings, separation of the tailboom from the helicopter, and subsequent loss of control of the helicopter.
Which aircraft AD 2006-08-12 applies to
Applies only to helicopters with serial numbers with a prefix 'RN' and 003 through 058, that have not been modified in the fuselage aft section to strengthen the tailboom attachments and longerons in accordance with MD Helicopters Technical Bulletin TB600N-007, dated January 12, 2004, or TB600N-007, Revision 1, dated April 13, 2006. Certificated in any category.
Whether AD 2006-08-12 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.