Airworthiness Directive 2011-14-05
one-timeAirworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters
What this AD requires
This amendment supersedes an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model MD900 helicopters. That AD currently requires visually inspecting the main rotor lower hub assembly (lower hub) for a crack, and if you find a crack, before further flight, replacing the unairworthy lower hub with an airworthy lower hub. Additionally, within 10 days of finding a cracked lower hub, the existing AD requires reporting the finding to the Los Angeles Aircraft Certification Office (LAACO). That AD was prompted by two reports of cracks detected in the hub in the area near the flex beam bolt hole locations during maintenance on two MDHI Model MD900 helicopters. Since we issued that AD, we determined that one manufacturer had incorrectly inserted flanged bushings into the lower hub bore that resulted in local corrosion, leading to fatigue cracking. Examination of lower hubs from the other manufacturer shows correct bushing installation. Therefore, this amendment limits the applicability to the affected lower hubs; retains the visual inspection but at a different compliance time; adds an eddy current inspection; retains the requirement to replace a cracked lower hub with an airworthy lower hub before further flight; and removes the requirement to report to the LAACO. The actions specified by this AD are intended to detect a crack in the lower hub and prevent failure of the lower hub and subsequent loss of control of the helicopter.
Which aircraft AD 2011-14-05 applies to
Applicability depends on the aircraft’s type certificate — check it against the specific tail.
Whether AD 2011-14-05 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.