MS29513-014 - Textron Aviation OEM Nitrile Preformed O-Ring Seal

MS29513-014 – Textron Aviation Nitrile (Buna-N) O-Ring Seal

Available now on the Airparts.aero Marketplace.

The MS29513-014 is a high-quality, preformed O-ring packing manufactured in strict accordance with Military Standard MS29513. While specified in Textron Aviation parts catalogs, it is a universal component used across the aerospace industry for general-purpose static sealing applications. This O-ring is fabricated from a 75 durometer Nitrile (Buna-N) synthetic rubber compound, the industry-standard material for sealing petroleum-based fluids. Its primary function is to prevent leakage in a vast range of hydraulic, fuel, and lubrication systems found throughout the airframe and on the engine.

The MS29513 specification (which supersedes the older AN6227B standard) guarantees that the O-ring meets the stringent requirements for material composition, dimensional tolerance, and quality control demanded by the FAA and military for certified aircraft. The use of the correct, certified MS-standard O-ring is a fundamental requirement for the airworthiness and safety of any fluid system.

Key Features

• Military Standard (MS) Certified: Manufactured to the exact material, hardness, and dimensional tolerances of the MS29513 specification, ensuring reliable sealing performance.

• Nitrile (Buna-N) 75 Durometer Material: The specified elastomer provides excellent resistance to petroleum-based hydraulic fluids (e.g., MIL-PRF-5606), engine oils, greases, and aviation gasoline.

• Sets a Reliable Static Seal: When compressed in a properly designed groove, it creates a positive, leak-free seal energized by system pressure.

• Wide Operating Temperature Range: Maintains its sealing integrity and physical properties across a broad temperature spectrum suitable for most airframe and engine applications (approx. -65°F to 275°F).

• Supersedes AN6227B-14: This is the modern military standard part, directly replacing the older AN-specification O-ring.

Technical Specifications

• Part Number: MS29513-014

• Component Type: Preformed Packing, O-Ring

• Governing Specification: MS29513

• Supersedes: AN6227B-14

• OEM Applicability: Textron Aviation (Cessna, Beechcraft), and all other manufacturers utilizing MS-standard components.

• Material: Nitrile Rubber (Buna-N / NBR).

• Hardness: 75 Durometer Shore A.

• Size (AS568A Dash Number): -014

• Dimensions:

  • Inside Diameter: 0.549 inches (13.94 mm)

  • Cross-Section: 0.103 inches (2.62 mm)

Aircraft Compatibility

The MS29513-014 is a standard hardware component used in countless applications across all categories of certified aircraft. It is not specific to any one airframe but is called for by part number in the maintenance and parts manuals for numerous systems and components.

Crucial Note: The correct part number for a specific application must be verified against the Illustrated Parts Catalog (IPC) or Component Maintenance Manual (CMM) for the component or aircraft being serviced.

Applications

The MS29513-014 is the workhorse O-ring for general-purpose static sealing in systems that use petroleum-based fluids. Common applications include:

• Hydraulic System Components (using MIL-PRF-5606 fluid)

• Engine Lubrication System fittings and accessories

• Fuel System Components (sealing housings and fittings)

• Landing Gear and Brake System Components

• Propeller Governor and Hub Sealing

Why Choose MS29513-014?

Choosing a genuine MS29513-014 O-ring is a critical decision for ensuring system integrity. The selection of an O-ring's material must be matched to the system's fluid. Using an incorrect elastomer (e.g., an EPDM or Silicone O-ring in a petroleum oil system) would lead to rapid chemical attack, causing the seal to swell, soften, and fail, resulting in a system leak. The MS standard guarantees the correct Nitrile material, quality control (free of nicks, cuts, or molding flaws), and dimensional accuracy required for a reliable, long-lasting seal in a certified aviation environment.

The specification of Nitrile rubber (Acrylonitrile Butadiene Rubber - NBR) for the MS29513 standard is based on fundamental polymer chemistry. NBR is a copolymer, and its exceptional resistance to non-polar fluids like petroleum oil and hydrocarbon fuel is determined by its acrylonitrile (ACN) content. The ACN monomer introduces polar nitrile groups (-C≡N) into the polymer chain. These polar groups are not chemically attracted to the non-polar hydrocarbon molecules of the fluid. This principle of "like dissolves like" (or in this case, "polar repels non-polar") prevents the fluid's molecules from permeating and swelling the polymer matrix, a process that would cause the O-ring to lose its hardness, reduce its sealing force, and ultimately fail. The MS29513 standard mandates a specific ACN content range and cure state to ensure this fluid resistance is consistently achieved, providing a reliable seal in the presence of petroleum-based products where an incompatible elastomer like Silicone or EPDM would rapidly degrade.

Note: O-rings are typically considered single-use components in aerospace applications and must be replaced whenever a fitting is disconnected or a component is disassembled. These components have a finite shelf life (cure date) which must be strictly observed. During installation, ensure the O-ring and gland are free of debris and sharp edges. The O-ring should be lightly lubricated with clean system fluid to prevent abrasion or cutting during assembly. Installation must be performed by a certified A&P mechanic in accordance with the applicable maintenance manual.

Documentation

The definitive technical requirements for this component are detailed in Military Standard MS29513. These proprietary documents must be sourced directly from the relevant standards organizations for complete engineering specifications.