NAS577B8A

BARREL NUT

Specifications

Part Number: NAS577B8A
Manufacturer: Bell
ATA ChapterMaintenance system chapter: 57 — Wings
CapabilitySystem area (hydraulics, avionics, landing gear…): Consumables / Hardware
Inventory ClassRotable, expendable, or consumable: —
Certification: —
Aircraft Category: Rotorcraft
Criticality: Standard

Service Reliabilityfrom FAA SDR (Service Difficulty Reports)

—

Component-change rate (FAA K-code)*

low confidence

* Structural ATA chapter (57). Verb-based propensity is suppressed because "REPAIRED" in the SDR text typically refers to the airframe being repaired around the part, not the part itself. FAA K-code component-change rate is the honest signal.

SDR reports: 2
Replace events: 1
Repair events: 0
K-code events: 2

Reporting window 2003-01-10 – 2015-01-12Dominant chapter ATA 57

Directional indicator only. Reflects what operators reported to the FAA when a difficulty was logged — not a fleet-normalized failure rate or a cost-based BER. Use alongside operator-specific data.

Airworthiness Directive coverage

FAA / EASA public regulatory data

4directives reference this part number — recurring compliance demand wherever it flies

Most recent

FAAAD 2024-16-19effective Nov 8, 2024Prohibition
The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Inc. Model 212, 412, 412CF, and 412EP helicopters. This AD was prompted by reports of cracked tail boom attachment barrel nuts (barrel nuts). This AD requires replacing all steel alloy barrel nuts with nickel alloy barrel nuts, replacing or inspecting other tail boom attachment point hardware, repetitively inspecting torque, and repetitively replacing tail boom attachment bolts (bolts). This AD also prohibits installing steel alloy barrel nuts. The FAA is issuing this AD to address the unsafe condition on these products.
FAAAD 2024-17-02effective Nov 8, 2024Prohibition
The FAA is adopting a new airworthiness directive (AD) for all Bell Textron Inc. (Bell) Model 204B, 205A, 205A-1, 205B, and 210 helicopters. This AD was prompted by an accident and incidents involving failure of the tail boom attachment structure. This AD requires inspecting the tail boom assembly hardware, replacing tail boom attachment hardware, greasing the bolt shanks, and inspecting torque. This AD also prohibits installing steel alloy nuts on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
EASAAD 2022-0046effective Mar 24, 2022Mixed actions
No summary available - see the EASA publication.
EASAAD 2022-0035effective Mar 14, 2022Mixed actions
No summary available - see the EASA publication.

Directives citing this part number in the FAA / EASA regulatory corpus we have processed — not a complete historical AD list. An AD is a compliance requirement that drives scheduled work (inspections, replacements, modifications) on the fleets that carry the part; a directive naming this PN as the replacement part is install demand, not an action against it — and none of this is a prediction that the part will fail.