MS21042L5

Name: MS21042L5
SKU: MS21042L5

LOCK NUT

PMA

Specifications

Part Number: MS21042L5
Manufacturer: —
ATA ChapterMaintenance system chapter: 57 — WingsField reports: 55 (50%) · 57 (50%) — 4 reports
CapabilitySystem area (hydraulics, avionics, landing gear…): Consumables / Hardware
Inventory ClassRotable, expendable, or consumable: Consumable
Certification: PMA
Aircraft Category: Unknown
Criticality: Standard
Life & ShelfTypical service/shelf life — verify against OEM data: —

Service Reliabilityfrom FAA SDR (Service Difficulty Reports)

80%

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: 5
Replace events: 4
Repair events: 0
K-code events: 4

Reporting window 1997-05-16 – 2012-10-15Dominant 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

2directives reference this part number — recurring compliance demand wherever it flies

Most recent

FAAAD 2022-20-04effective Dec 23, 2022ProhibitionNamed as replacement part
The FAA is superseding airworthiness directive (AD) 2021-26- 08, which applied to certain Bell Textron Canada Limited Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. AD 2021-26-08 required removing certain nuts from service; installing newly designed nuts; applying a specific torque, and a torque stripe to each newly installed nut; after the installation of each newly designed nut, inspecting the torque; and depending on the inspection results, either applying a torque stripe, or performing further inspections and removing certain parts from service. AD 2021- 26-08 also prohibited installing any affected nut on any tail rotor drive shaft (TRDS) disc pack (Thomas) coupling. Since the FAA issued AD 2021-26-08, the FAA determined certain torque values and part numbers (P/Ns) need to be revised. This AD was prompted by reports of cracked or missing nuts installed on the TRDS Thomas couplings and the need to revise certain torque values and P/Ns in AD 2021-26-08. This AD requires removing certain nuts from service; installing newly designed nuts; applying torque and a torque stripe; and additional corrective actions if necessary. This AD also prohibits installing any affected nut on any TRDS Thomas coupling, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
FAAAD 2021-26-08effective Jan 27, 2022ProhibitionNamed as replacement part
The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. This AD was prompted by reports of cracked or missing nuts on the tail rotor drive shaft (TRDS) disc pack (Thomas) couplings. This AD requires removing certain nuts from service, installing newly designed nuts, and applying a specific torque and a torque stripe to each newly installed nut. This AD then requires, after the installation of each newly designed nut, inspecting the torque and, depending on the inspection results, either applying a torque stripe or performing further inspections and removing certain parts from service. Finally, this AD prohibits installing any affected nut on any TRDS Thomas coupling. The FAA is issuing this AD to address the unsafe condition on these products.

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.