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NAS1149D0416K – Textron Aviation OEM High-Strength Aluminum Flat Washer
Available now on the Airparts.aero Marketplace.
The Textron Aviation NAS1149D0416K is a precision-engineered structural flat washer manufactured to the National Aerospace Standard (NAS) and certified as an OEM component for the Textron fleet, including Cessna, Beechcraft, and Hawker aircraft. Specifically designed to replace the legacy AN960 series, the NAS1149 standard provides tighter dimensional tolerances and more stringent material controls. The "D" code signifies that this washer is fabricated from 2024-T3 aluminum alloy, a high-strength material chosen for its exceptional strength-to-weight ratio and fatigue resistance in demanding airframe environments.
As a "Regular" thickness washer, the NAS1149D0416K provides a robust bearing surface and precise load distribution under the heads of bolts or nuts. Its primary engineering function is to protect the underlying aircraft skin or structural component from "marring" and to prevent the fastener from "sinking" into the material, which would cause an immediate loss of critical preload. Finished with a Type II yellow dichromate chemical conversion coating, this washer offers excellent corrosion protection and electrical bonding properties. For Textron operators, utilizing this OEM-certified hardware ensures that every structural joint maintains the exact engineering margins specified in the aircraft's original Type Certificate.
Key Features
2024-T3 Aluminum Alloy: Offers high tensile strength and stiffness while remaining significantly lighter than steel alternatives, essential for weight-sensitive aerospace applications.
Precision Textron OEM Tolerance: Manufactured to the modern NAS1149 standard, ensuring consistent inner and outer diameters that meet Textron Aviation’s stringent Quality Assurance requirements.
Chemical Conversion Coating: Treated with MIL-DTL-5541 (Yellow) for superior galvanic corrosion resistance and improved paint adhesion.
Structural Load Distribution: Increases the bearing area under the fastener, reducing the localized compressive stress on the airframe structure.
Fatigue-Optimized Design: Surfaces are precision-stamped and deburred to eliminate stress risers that could initiate cracks in the primary airframe structure.
Technical Specifications
Part Number: NAS1149D0416K
OEM Manufacturer: Textron Aviation (Cessna / Beechcraft / Hawker)3
Standard: NAS1149 (Supersedes AN960)
Material: 2024-T3 Aluminum Alloy
Finish: Chemical Conversion Coating (Yellow), per MIL-DTL-5541
Fastener Size: 1/4 inch (0.250")
Inside Diameter (ID): 0.255" – 0.275"
Outside Diameter (OD): 0.495" – 0.510"
Thickness: 0.051" – 0.075" (Regular Weight)
Governing Specifications: NAS1149, MIL-A-8625 or MIL-DTL-5541
Certification: FAA-PMA / Textron OEM Standard Hardware
Aircraft Compatibility
Cessna 172, 182, 206, and 210 Series
Cessna 208 Caravan and 208B Grand Caravan
Beechcraft Bonanza (33/35/36) and Baron (55/58)
Beechcraft King Air 90, 200, and 300 Series
Hawker 400XP / 800XP
Note: While a standard fastener, always consult the specific aircraft Illustrated Parts Catalog (IPC) to verify the correct material (Aluminum vs. Steel) for the installation zone.
Applications
Airframe Skin Fastening: Distributing loads on aluminum fuselage skins and wing panels.
Control Surface Mounting: Used in hinges and brackets for elevators, ailerons, and rudders.
Interior Secondary Structures: Securing seat tracks, floor panels, and cabin cabinetry where weight reduction is critical.
Why Choose NAS1149D0416K?
In aerospace structural joinery, the choice of washer material is critical to preventing Galvanic Corrosion. The NAS1149D0416K is specifically designed for use with aluminum structures, as its aluminum-alloy composition minimizes the electrical potential difference that leads to "hidden corrosion" inside a joint. Furthermore, the 2024-T3 material ensures the washer will not undergo compressive creep—a failure mode where softer materials thin out over time, causing the bolt to lose tension. By choosing Textron OEM hardware, you ensure full traceability and adherence to the metallurgical standards required for continued airworthiness.
The NAS1149D0416K utilizes the engineering principle of Bearing Stress Management within a Clamped Joint. When a 1/4" bolt is torqued, it exerts an axial force that must be distributed over a sufficient surface area to stay below the Compressive Yield Strength of the airframe material. Because this washer is fabricated from 2024-T3, it benefits from precipitation-strengthening, which provides the hardness required to resist "brinelling" (permanent indentation) under the bolt head.
From a materials science perspective, the Chemical Conversion Coating is vital for preventing Intergranular Corrosion. The high copper content in 2024 aluminum makes it susceptible to localized galvanic cells within the grain boundaries.9 The conversion coating creates a passive barrier that interrupts the electrolyte path. Additionally, this finish ensures a stable Nut Factor ($K$), allowing for repeatable torque-to-tension conversions, which is critical for maintaining the Fatigue Limit of the structural assembly under cyclic aerodynamic loading.
Note: The NAS1149D0416K is a structural component. It should be inspected for any signs of corrosion, deformation, or scratches in the protective coating prior to installation. Aluminum washers must never be substituted for steel washers in high-temperature or high-strength applications (such as engine mounts or landing gear primary pivots) unless explicitly authorized by the Aircraft Maintenance Manual (AMM). Installation must be performed by a certified A&P mechanic in accordance with AC 43.13-1B.
Documentation
Applicable Aircraft
- 1900 Airliner
- 1900D Airliner
- Baron Series B55, E55, 58 or G58
- Bonanza 36
- Caravan or Grand Caravan EX
- Citation CJ1 or CJ1+
- Citation CJ2 or CJ2+
- Citation CJ3, CJ3+, CJ3+ Gen 2, CJ3 Gen 3
- Citation CJ4, CJ4 Gen 2, CJ4 Gen 3
- Citation Excel, XLS, XLS+, XLS Gen 2
- Citation III, VI or VII
- Citation Latitude
- Citation M2, M2 Gen 2, M2 Gen 3
- Citation Mustang
- Citation Sovereign or Sovereign+
- Citation V, Ultra, Encore or Encore+
- Citation X
- Citation X+
- King Air B200, B200T, B200C or B200CT
- Premier Model 390
- SkyCourier
- 767-200EREM
- B200C
- B36TC
- 777-200LR
- 787-10
- C90A
- A330-200
- A36TC
- 767-300EREM
- B200CT
- ERJ-190-100 IGW
- 737-300F
- 757-300
- 1900C
- B200T
- 767-200ERT
- C90SE
- ERJ-170-100 SU
- CRJ-900ER
- 737-700C
- 777
- Citation Bravo
- A36TC
- 787
- CRJ-701ER
- 747-400
- CRJ-700ER
- 750
- Bonanza G36
- ERJ-190-100 LR
- 1900
- 1900D
- 737-400SF
- 767-300F
- C90GT
- 747-8
- 767-300ER
- B200T
- 1900D
- 737-600
- 767-200
- ERJ-170-100 LR
- 737-100
- 737-300SF
- A320-200
- ERJ-170-200 LR
- 737-500
- A36
- C90GTx
- 1900
- 777-300ER
- ERJ-170-200 SU
- 36
- 707
- CRJ-702
- CRJ-200
- 767-200ER
- CRJ-100
- 767
- A340-300
- ERJ-170-200 IGW
- A320-200 NEO
- CRJ-900LR
- 407
- 777-200ER
- B58
- 777-200F
- 737-300
- CRJ-440
- 1900C
- CRJ-701
- 777-9
- A340-600
- B200
- 727-100
- 900XP
- 757
- 757-200PCF
- 757-300EM
- C90GTi
- 767-200SF
- 767-400ER
- E90
- ERJ-170-200
- 208
- 737-300QC
- 777-300
- 787-9
- E55
- B200
- CRJ-702ER
- E55
- 767-400
- 737-800
- A321-200
- A36
- A340-500
- B36TC
- C90-1
- 36
- B55
- 757-200EM
- C90A
- 737-700
- BBJ 737-800
- 737-900
- A330-300
- ERJ-170-200 LL
- ERJ-190-200 IGW
- 777-200
- 787-8
- ERJ-170-100 SE
- ERJ-190-200 LR
- 757-200
- C90
- C90B
- A319-100
- 767-300BCF
- ERJ-170-100
- 757-200PF
- 767-300
- ERJ-190-100 ECJ
- BBJ 737-700
- B200CT
- CRJ-900
- 747
- CRJ-700
- ERJ-190-100
- A321-100
- A340-200
- 737-200
- 737-400
- ERJ-190-200
- 757-200PC
- CRJ-705
- A321-200 NEO
List not comprehensive, may be applicable on other models.
