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Airworthiness Directive 95-21-12

recurring
Official AD 95-21-12 · FR doc 95-25522 · 1995-10-16 · airframe

Airworthiness Directives; Eurocopter Deutschland GmbH (ECD) 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), applicable to Eurocopter Deutschland GmbH (ECD) (Eurocopter) Model MBB- BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, that requires initial and repetitive inspections of the main rotor (M/R) blade upper and lower surfaces for bulging. This amendment is prompted by two reported incidents in which a balance weight became detached from inside the M/R blade structure and migrated toward the tip of the M/R blade. The actions specified by this AD are intended to detect movement of a balance weight and to prevent severe vibrations and a subsequent precautionary landing.

Repetitive inspection. Re-inspect. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 95-21-12 applies to

MakesEurocopter Deutschland GmbhMbb
ModelsBK117

Within 5 hrs TIS and thereafter every 50 hrs TIS, visually inspect upper/lower surfaces of main rotor blades near the outboard lead balance weight for bulging (mark inspection area if not already marked); if bulging exceeds 1mm (0.040 in), remove and replace blade with an airworthy blade. Per Eurocopter Deutschland (ECD) Alert SB ASB-MBB-BK 117-10-108 Rev 1.

Whether AD 95-21-12 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:

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 95-21-12 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.