Airworthiness Directive 2004-05-29
one-timeAirworthiness Directives; Eurocopter France Model EC 155B Helicopters
What this AD requires
This amendment adopts a new airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) model helicopters that requires installing a tail rotor blade (blade)-to-torsion bar attachment tuning weight assembly on each blade of the Quiet Fenestron tail rotor and replacing each blade attachment bushing. This amendment is prompted by the discovery of tail rotor induced vibrations during flight tests. The actions specified by this AD are intended to prevent vibration in the tail rotor and the pilot's anti-torque pedals, blade pitch control failure, and subsequent loss of control of the helicopter.
Which aircraft AD 2004-05-29 applies to
Applies only if an upgraded Quiet Fenestron tail rotor hub P/N 365A33-3501-02, tail rotor attachment bushing P/N 365A33-3530-20, and either tail rotor gearbox P/N 365A33-6005-04 (without reinforced control shaft P/N 365A33-6161-21) or tail rotor gearbox P/N 365A33-6005-06 (with reinforced control shaft P/N 365A33-6214-20) are installed.
Whether AD 2004-05-29 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.