AN806-3 - Textron Aviation OEM Aerospace Steel Flared Threaded Tube Plug 3/16 Thread

AN806-3 – Aerospace Steel Flared Threaded Tube Plug

Available now on the Airparts.aero Marketplace.

Overview

The AN806-3 is a military-standard, hexagonal head flared tube plug, an essential piece of hardware for the maintenance and sealing of aerospace fluid systems. Manufactured in strict accordance with Air Force/Navy (AN) standards, this plug is precision-machined from high-strength carbon steel. Its primary function is to provide a positive, leak-proof seal on open 37-degree flared fittings, protecting hydraulic, fuel, and oil systems from contamination and fluid loss during maintenance or for permanent system blanking.

Key Features

• 37-Degree Flare Seal: Features a precision-machined 37° flared cone on its tip. This is designed to mate perfectly with the 37° seating surface of a standard AN fitting, creating a highly reliable metal-to-metal seal when torqued.
• High-Strength Steel Construction: Fabricated from a high-quality carbon steel alloy, providing the strength and durability to be installed and removed multiple times without damaging the threads or the head.
• Corrosion-Resistant Plating: Plated with a durable cadmium finish per applicable military specifications. This protective coating provides excellent resistance to corrosion from hydraulic fluids, fuels, and environmental exposure.
• Hexagonal Head Design: Equipped with a standard hexagonal head, allowing for easy installation and removal with a standard wrench or socket, and enabling the application of proper torque values.
• AN Certified Standard: As a certified AN-standard part, it guarantees full interchangeability with any other -3 AN fitting, as well as the material strength and dimensional accuracy required for certified aircraft applications.

Technical Specifications

• Standard: AN806 (Plug, Flared Tube)
• Full Part Number: AN806-3
• Material: Carbon Steel
• Finish: Cadmium Plated
• Head Style: Hexagonal (Hex Head)
• Fitting Size (Dash Size): -3 (for 3/16 inch tube fittings)
• Thread Specification: 3/8-24 UNF-3A
• Flare Angle: 37°

Aircraft Compatibility

The AN806-3 is a universal piece of hardware used on virtually every type of aircraft that utilizes standard AN fluid fittings. Its use is essential for any maintenance activity involving the disconnection of fluid lines.

• Common Systems:
  • Hydraulic Systems: Capping open lines during replacement of actuators, pumps, or brake components.
  • Fuel Systems: Sealing fuel lines when replacing fuel selectors, pumps, or filters to prevent contamination and fuel spillage.
  • Oil Systems: Plugging oil lines during the replacement of oil coolers, propellers, or engine sensors.

Applications

The AN806-3 is a critical tool for safe and clean aircraft maintenance:

• System Capping & Protection: Its primary application is to cap off open AN fittings on hoses or components that have been removed from the aircraft for service. This keeps the internal system clean and prevents fluid leaks.
• Pressure Testing: Can be used to seal off ports when performing pressure tests on a fluid system or component.
• Permanent Blanking: In some modifications, it may be used to permanently seal an unused port in a fluid system manifold or component.

Why Choose AN806-3?

During aircraft maintenance, preventing contamination of hydraulic, fuel, and oil systems is paramount. A single piece of dirt or debris can cause a valve to jam or a component to fail. The AN806-3 provides a secure, positive seal, far superior to using tape or plastic caps. Using a genuine AN-standard steel plug ensures the part has the strength to be properly torqued without stripping and the correct 37° flare for a perfect seal. It is an essential and inexpensive tool for any professional A&P mechanic's toolbox.

Order Your AN806-3 Plugs Now

Protect your aircraft's critical fluid systems during maintenance with certified AN-standard hardware. Visit Airparts.aero to order your AN806-3 flared tube plugs today.

The AN806-3 plug creates a seal based on the same principle as a standard AN hose connection. The 37-degree flared cone on the plug acts as a male counterpart to the female cone inside an open AN fitting. When the plug's threads are engaged and torqued, the two cones are forced together with immense pressure. This pressure creates a small, circular line of contact where the metal is slightly deformed, creating a perfect, high-pressure, metal-to-metal seal. Unlike pipe threads, this design does not require any thread sealant and can be reused multiple times (pending inspection) without losing its sealing capability.

Note: When installing, ensure the fitting's flare and the plug's flare are clean and free of nicks or scratches. Tighten to the torque value specified for a -3 AN fitting in standard aviation maintenance handbooks (like AC 43.13-1B). Do not overtighten.