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Airworthiness Directive 2004-01-10

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Official AD 2004-01-10 · FR doc 04-267 · 2004-01-07 · airframe

Airworthiness Directives; Eurocopter Deutschland Model MBB-BK-117 A-1, A-3, A-4, B-1, B-2, and C-1 Helicopters

What this AD requires

This amendment adopts a new airworthiness directive (AD) for Eurocopter Deutschland (Eurocopter) Model MBB-BK-117 A-1, A-3, A-4, B- 1, B-2, and C-1 helicopters with a certain tail rotor (TR) transmission or intermediate (INT) gearbox installed. This action requires inspecting the magnetic plug of the TR transmission and INT gearbox for metal particles before the first flight of each day. Replacing an unairworthy TR transmission, INT gearbox, or bearings with airworthy parts is also required within 30 days after the effective date of this AD. This amendment is prompted by a report of production-related cracks on the cage of bearings installed in certain TR transmissions and INT gearboxes. This condition, if not corrected, could result in cracking and separation of the bearing cage, failure of a bearing, failure of the TR transmission or INT gearbox, and subsequent loss of control of the helicopter.

Which aircraft AD 2004-01-10 applies to

MakesMbb
ModelsBK117A-1, BK117A-3, BK117A-4, BK117B-1, BK117B-2, BK117C-1, BK117
Serial-conditional — narrows to serials 900–932, 902–928, 3246–3598.
Part-conditional — 4639003001, 4639003007, 4639310006, 4639002001, 4639002005.

Applies only if equipped with either (a) TR transmission P/N 4639003001 or 4639003007, S/N 900 through 932 (plus any S/N overhauled or repaired after July 15, 2001), and bearing P/N 4639310006, S/N 3246 through 3598; or (b) INT gearbox P/N 4639002001 or 4639002005, S/N 902 through 928 (plus any S/N overhauled or repaired after July 15, 2001), and bearing P/N 4639310006, S/N 3246 through 3598.

Whether AD 2004-01-10 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:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.
Date — When the work was done.
Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.
Signature & certificate — The A&P/IA who returned it to service, with certificate number.
Is AD 2004-01-10 complied with on your aircraft?

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.