A-1373 - Textron Aviation OEM Hex Head Self Locking Aerospace Nut 7/16-20

A-1373 – Textron Aviation OEM Hex Head Self Locking Aerospace Nut 7/16-20

Available now on the Airparts.aero Marketplace.

Overview

The Textron Aviation A-1373 is a genuine OEM, flight-critical, all-metal self-locking hexagon nut, engineered for high-stress structural applications on various Beechcraft aircraft. This is not a standard hardware store nut; it is a high-strength, prevailing torque locknut designed to resist loosening under the most severe vibration and load conditions. Fabricated from a high-strength, cadmium-plated steel alloy, the A-1373 is specified for use in areas where both high strength and elevated temperatures would cause a standard nylon insert locknut to fail.

Key Features

• All-Metal Locking Design: Features a precision-deformed elliptical thread at the top of the nut. This all-metal locking mechanism creates a powerful spring-like frictional grip on the bolt threads, providing a consistent prevailing torque that is resistant to high temperatures and vibration.
• High-Temperature Capability: The absence of a non-metallic (nylon) insert allows this nut to maintain its structural and locking integrity at moderately high temperatures (typically up to 450°F), making it suitable for many firewall-forward and landing gear applications.
• High-Strength Steel Construction: Fabricated from a high-quality steel alloy and heat-treated to provide the high tensile strength required to properly preload large-diameter AN structural bolts.
• Corrosion-Resistant Plating: Plated with a durable cadmium finish to provide robust protection against corrosion, ensuring a long and reliable service life in demanding airframe environments.
• Genuine Textron OEM Part: As a genuine factory component specified for Beechcraft aircraft, it guarantees conformance to the stringent material, heat treatment, and locking torque specifications required for a flight-critical, structural fastener.

Technical Specifications

• Part Number: A-1373
• Component Type: All-Metal Prevailing Torque Self-Locking Nut
• Material: High-Strength Steel Alloy
• Finish: Cadmitum Plated
• Thread Specification: 7/16-20 UNF
  • Nominal Diameter: 7/16 inch (0.4375 inches)
  • Threads Per Inch: 20 (Fine Thread)
• Wrench Size: 5/8 inch
• Maximum Operating Temperature: Approx. 450°F (232°C)
• Certification: FAA Production Approval

Aircraft Compatibility

The A-1373 is a critical structural fastener used across a wide range of legacy and current production Beechcraft aircraft. It is imperative to consult the specific aircraft's Illustrated Parts Catalog (IPC) for final verification.

• Common Aircraft Models:
  • Beechcraft Bonanza: 35, 36 Series
  • Beechcraft Baron: 55, 58 Series
  • Beechcraft King Air: 90, 100, 200 Series
  • Beechcraft Duke & Debonair
• Common Applications:
  • Landing Gear Systems: Securing major structural components of the main and nose landing gear.
  • Engine Mounts: Used in the engine mount to firewall attachment points.
  • Primary Airframe Structure: Used in various high-stress wing and fuselage structural joints.

Applications

The A-1373 is the specified fastener for creating secure, high-strength joints in challenging environments:

• Heat-Resistant Fastening: Provides a reliable, vibration-proof connection in areas that are too hot for standard AN365 / MS21044 nyloc nuts.
• Structural Integrity: The specified nut for ensuring critical bolted joints are properly preloaded and remain secure for the life of the airframe.

Why Choose A-1373?

The failure of a structural nut in a landing gear or engine mount application would be catastrophic. The Textron Aviation A-1373 is the only component certified by the manufacturer to provide the required strength and reliable locking action for these critical joints. Its all-metal design ensures it will not fail or lose its locking properties when exposed to the high temperatures of the engine compartment or the heat generated during braking. For a flight-critical fastener, there is no substitute for a genuine, fully traceable OEM part.

Order Your A-1373 Nuts Now

Ensure the structural integrity of your aircraft with genuine, factory-certified OEM hardware. Visit Airparts.aero to order your Textron Aviation A-1373 self-locking nuts today.

The locking mechanism of the A-1373 is achieved through controlled thread deformation. During manufacturing, the top one or two threads of the nut are precisely deflected inward at opposing points, creating a slightly non-circular shape. As a standard male bolt thread enters this section, it must elastically deflect the deformed nut threads back into a circular shape. This creates a powerful spring-like clamping force, or friction grip, on the flanks of the bolt threads. This purely mechanical interference creates the "prevailing torque" that resists rotation from vibration. Because this mechanism relies solely on the resiliency of the heat-treated steel, it remains effective at temperatures up to 450°F, far beyond the melting point of a nylon polymer insert.

Note: This is a flight-critical structural component. It must be tightened using a calibrated torque wrench to the value specified in the applicable maintenance manual. While reusable, the nut must be discarded if its prevailing torque falls below the minimum specified value, which can be checked with a torque wrench before the nut is seated.