SP123D - Textron Aviation OEM Flat Washer

SP123D – Textron Aviation OEM Flat Washer

Available now on the Airparts.aero Marketplace.

Overview

The SP123D is a flat washer manufactured to a proprietary Textron Aviation design standard for use in specific applications across their aircraft fleet. Unlike common AN or NAS standard washers, this component is governed by a specific Textron engineering drawing, which dictates its precise dimensions, material, hardness, and finish. As an Original Equipment Manufacturer (OEM) controlled part, it is engineered to meet a particular requirement within a bolted joint that a standard off-the-shelf washer cannot.

The fundamental purpose of this washer remains aligned with core engineering principles: to uniformly distribute the compressive load from a bolt head or nut over a wider surface area, protecting the structure from damage, and to provide a consistent, smooth bearing surface for accurate torque application. By procuring the genuine SP123D, maintainers are ensuring they are installing a fully certified, traceable component that maintains the aircraft's original type-certified design and structural integrity.

Key Features

• Textron Aviation OEM Certified: Guarantees the part is fabricated to the exact Textron engineering drawing, ensuring perfect fit, form, and function.

• Application-Specific Design: The material and dimensions are precisely controlled by the OEM to meet the specific load, clearance, and environmental requirements of its intended location.

• Governed by OEM Drawing: All technical attributes are defined by a proprietary Textron Aviation specification, ensuring a level of control beyond standard hardware.

• Critical Load Distribution: Engineered to prevent galling, marring, and yielding of softer structural materials under the high clamp loads of a torqued fastener.

• Optimized Bearing Surface: Provides the ideal surface characteristics to ensure that torque applied to the fastener is converted into the correct bolt preload.

Technical Specifications

• Part Number: SP123D

• Component Type: Flat Washer

• OEM Authority: Textron Aviation

• Governing Specification: Textron Aviation Engineering Drawing SP123D

• Material: Must be confirmed by Textron Aviation documentation. Common materials for such applications include Cadmium Plated Steel, Corrosion Resistant Steel (CRES), or Anodized Aluminum Alloy.

• Dimensions (ID, OD, Thickness): Must be confirmed by Textron Aviation documentation. These dimensions are specific to the part number and its application.

• Finish: Per the proprietary Textron Aviation drawing specification.

Aircraft Compatibility

This washer is used on specific Textron Aviation aircraft models where the part number SP123D is explicitly called out in the manufacturer's documentation.

• Applicable Platforms May Include:

  • Cessna Citation Series Business Jets

  • Beechcraft King Air, Baron, and Bonanza

  • Cessna Caravan and Piston Aircraft

  • Hawker Business Jets

Note: Verification of applicability is the absolute responsibility of the installer. The aircraft's current Illustrated Parts Catalog (IPC) is the final authority for confirming part number eligibility for a specific serial number and location.

Applications

• For use under bolt heads and nuts in specific airframe, powerplant, or systems installations where the SP123D part number is mandated by the Textron Aviation engineering drawing or maintenance manual.

Why Choose SP123D?

When an airframe manufacturer like Textron Aviation specifies a proprietary part number for a seemingly standard item like a washer, it is for a critical engineering reason. The SP123D may have a non-standard thickness to act as a precision shim, a unique outer diameter to fit in a restricted space, or a specific material and hardness to manage electrical bonding or galvanic corrosion. Substituting a generic or "looks-like" washer is not permissible and would violate the aircraft's type certificate, potentially compromising the integrity of the joint. Only the genuine OEM part guarantees compliance and safety.

The engineering rationale for an OEM-specific hardware component like the SP123D often lies in solving a unique design challenge that cannot be met by the standardized dimensions or materials of the AN/NAS/MS systems. While standard parts are used for the majority of assemblies, certain critical joints may require a washer with a non-standard outer diameter to provide the necessary bearing area without interfering with an adjacent structure, a specific thickness to function as a calibrated shim for maintaining critical alignment, or a unique material composition to manage the electrochemical potential in a joint with unconventional alloys. An OEM-controlled part number like the SP123D is the mechanism by which the design authority ensures that this unique, engineered solution is implemented during both production and maintenance, with the full backing of OEM quality control and traceability.

Note: This is a flight-critical hardware component. Its specific material and dimensional characteristics are essential to its function. It must not be substituted with any other part. Installation must be performed by a certified mechanic in strict accordance with the aircraft maintenance manual. The washer must be clean and free of defects before installation.

Documentation

All technical data, including material, dimensions, and finish for the SP123D washer, are proprietary to Textron Aviation. This information is contained within the official Textron Aviation engineering drawings and can be referenced for a specific application through the aircraft's Illustrated Parts Catalog (IPC) and maintenance manuals. No public-facing documentation is available.