Airworthiness Directive 98-23-18
one-timeAirworthiness Directives; Bell Helicopter Textron, Inc. Model 214B, 214B-1, and 214ST Helicopters
What this AD requires
This amendment adopts a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. (Bell) Model 214B, 214B- 1, and 214ST helicopters. This action requires a visual inspection of thin-flanged attachment barrel nuts (barrel nuts) manufactured by Kaynar Technologies, Inc. for cracks or lubrication residue, and replacement of the barrel nuts and corresponding attaching bolts, as necessary. These barrel nuts have been installed in main rotor grips, pitch horns, and tailboom assemblies. This amendment is prompted by a report of a cracked barrel nut, which was discovered on a helicopter being prepared for shipment. The actions specified in this AD are intended to detect cracks in a barrel nut, which could lead to failure of a main rotor grip, pitch horn, or tailboom, and subsequent loss of control of the helicopter.
Which aircraft AD 98-23-18 applies to
Applies to Kaynar Technologies Inc.-manufactured barrel nut P/N NAS577B-10A identified as a 'thin' flange type (0.155-in. installed edge distance) at main rotor grip, pitch horn, or tailboom attachment points; 'thick' flange Kaynar nuts (0.115 in.) are excluded. Per Bell ASB 214-97-59 (214B/B-1) and ASB 214ST-97-78 (214ST).
Whether AD 98-23-18 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.