MS28775-222 - Textron Aviation OEM Packing O-Ring

MS28775-222 – Textron Aviation OEM Hydraulic O-Ring Packing

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Overview

The MS28775-222 is a military standard O-ring packing seal, supplied with the full certification and traceability of Textron Aviation as an Original Equipment Manufacturer (OEM) component. This seal is engineered for critical static and dynamic sealing applications within aircraft hydraulic systems utilizing petroleum-based fluids. Manufactured from a highly durable Nitrile Butadiene Rubber (NBR) compound (Buna-N), this component is specifically formulated for long-term compatibility with fluids such as MIL-H-5606. Its material properties and dimensional tolerances are governed by the MS28775 military specification, ensuring consistent quality and reliable performance.

Conforming to the AS568 dimensional standard for size -222, this O-ring provides a positive, leak-proof seal in numerous applications. As a genuine Textron Aviation part, it is the factory-specified component for maintaining the integrity of hydraulic systems on Cessna, Beechcraft, and Hawker aircraft. Sourcing this O-ring as an OEM part provides the highest level of assurance for airworthiness and compliance.

Key Features

• Genuine Textron Aviation OEM Part: Guarantees the part is the factory-specified and fully certified component, ensuring correct performance and airworthiness for Textron aircraft.

• Military Specification Compliance: Manufactured in strict accordance with the MS28775 standard, ensuring material integrity and performance.

• Petroleum Fluid Resistant: Formulated from a specific Nitrile (Buna-N) compound for superior, long-term resistance to petroleum-based hydraulic fluids, oils, and fuels.

• AS568 Standard Sizing: Precisely dimensioned to the AS568-222 standard (1.484" ID, 0.139" CS) for a perfect fit in corresponding glands.

• Extreme Temperature Performance: Engineered to maintain elasticity and sealing force in harsh thermal environments from -65°F to +275°F (-54°C to +135°C).

• Robust Mechanical Properties: Exhibits high tensile strength and superior resistance to abrasion and compression set, ensuring durability in both static and reciprocating dynamic seals.

Technical Specifications

• Part Number: MS28775-222

• Component Type: Hydraulic O-Ring Packing Seal

• OEM Authority: Textron Aviation

• Underlying Specification: MS28775

• Material: Nitrile Butadiene Rubber (NBR), Buna-N, 75 Durometer Shore A (Typical).

• Finish: N/A

• Dimensions (AS568-222):

  • Inside Diameter (ID): 1.484 inches

  • Cross-Section Diameter (CS): 0.139 inches

• Operational Temperature Range: -65°F to +275°F (-54°C to +135°C)

• Compatible Fluids: MIL-H-5606, MIL-PRF-83282, MIL-PRF-87257, and other petroleum-based hydrocarbon fluids.

• Certification: Shipped with Certificate of Conformance to MS28775 and Textron OEM traceability.

Aircraft Compatibility

As a Textron Aviation OEM part, this O-ring is the specified component for numerous applications across their product lines. It is also a standard hardware item used more broadly in aviation.

• Primary Textron Aviation Platforms:

  • Cessna Citation Series (various models)

  • Beechcraft King Air Series

  • Beechcraft Bonanza / Baron

  • Cessna Caravan Series

  • Hawker Business Jets

• General Aviation Usage: Used across all sectors of aviation employing MS-standard hydraulic seals for petroleum fluids.

Note: Verification of applicability is the responsibility of the installer. Always consult the current version of the aircraft's Illustrated Parts Catalog (IPC) and maintenance manual to confirm part number eligibility.

Applications

• Static Sealing: Provides a reliable seal for larger hydraulic line fittings, component flanges, plugs, and housings.

• Dynamic Sealing (Reciprocating): Used as piston and rod seals in hydraulic actuators and shock struts where an AS568-222 dimension is specified.

• Component Sealing: Integrated into hydraulic pumps, motors, servo-valves, and accumulators.

Why Choose this MS28775-222?

This component provides the dual assurance of meeting the public MS aerospace standard and the specific endorsement of Textron Aviation. Hydraulic system integrity is a flight-critical concern. Choosing this part guarantees the correct Nitrile compound, dimensions, and quality control specified by the aircraft manufacturer, eliminating the risks associated with generic, non-certified seals that could lead to leaks, system failure, and safety hazards.

The material science of the MS28775-222 is centered on its Nitrile Butadiene Rubber (NBR) composition, a synthetic elastomer created by copolymerizing acrylonitrile and butadiene. The high proportion of acrylonitrile in the polymer chain introduces polar nitrile groups which give the material its characteristic oleophobicity, or strong resistance to non-polar hydrocarbon fluids like MIL-H-5606. The physics of its sealing function are based on the principle of converting applied pressure into sealing force. The O-ring, an elastomeric torus, is installed into a gland with a predetermined diametrical squeeze. This creates an initial line of contact and a low-pressure seal. When the hydraulic system is pressurized, the fluid, acting according to Pascal's Law, exerts uniform pressure on the energized side of the O-ring. This pressure deforms the elastomer, forcing it against the clearance gap on the low-pressure side of the gland, which increases the sealing stress to a value that exceeds the system pressure, thus preventing leakage.

Note: This component is a flight-critical seal and is subject to a finite shelf life as defined by aerospace standard ARP5316. Always verify the cure date of the O-ring prior to installation. It is considered a single-use part in all dynamic and critical static applications. Installation must be performed by a certified mechanic in a clean environment. Use of the system's specified hydraulic fluid as a lubricant is required, and care must be taken to avoid nicking, cutting, or twisting the O-ring during installation.

Documentation

The base standard for this part is publicly available through the Department of Defense ASSIST database. OEM-specific application data is contained within the Textron Aviation maintenance and parts manuals.

• ASSIST Document Summary Page for MS28775: http://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=45248