0511771-8 – Textron Aviation OEM Nose Gear Torque Link Pin
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Overview
The 0511771-8 is a flight-critical, genuine Textron Aviation (Cessna) Original Equipment Manufacturer (OEM) pivot pin. This is not a generic piece of hardware; it is a highly engineered structural component designed to serve as the pivot axle for the nose landing gear torque link (or "scissors") assembly. Its function is to connect the upper and lower torque link arms, allowing them to pivot smoothly while preventing the nose wheel from rotating or castering freely. The integrity of this pin is absolutely essential for maintaining nose wheel alignment and preventing catastrophic nose wheel shimmy.
This pin is manufactured from a high-strength, heat-treated alloy steel and is precision-ground to an extremely tight diameter tolerance. This ensures a close running fit within the torque link bushings, minimizing play and withstanding the immense shear loads and dynamic impacts of ground operations. As the genuine OEM part, it is the only component guaranteed to possess the material strength, fracture toughness, and dimensional accuracy required for this no-compromise application.
Key Features
Genuine Textron Aviation OEM Part: Guarantees the part is the factory-specified and fully certified component, ensuring correct fit, material strength, and airworthiness.
High-Strength Heat-Treated Alloy Steel: Forged or machined from a premium alloy steel, then quenched and tempered to achieve the superior shear strength and fracture toughness needed for a landing gear component.
Precision-Ground for Close Fit: The shank is ground to an exacting diameter tolerance to ensure a proper, close running fit with the torque link bushings, which is critical for preventing shimmy.
Positive Locking Design: The pin is designed for use with a castellated nut and cotter pin, providing an infallible mechanical lock that is essential for a primary landing gear connection.
Corrosion-Resistant Plating: Typically plated with cadmium per QQ-P-416 for exceptional, long-term protection against corrosion in the harsh landing gear environment.
Flight-Critical Landing Gear Component: A primary structural pin in the nose gear assembly; its failure would lead to the collapse or uncontrollable shimmy of the nose gear.
Technical Specifications
Part Number: 0511771-8
Component Type: Nose Gear Torque Link Pin / Pivot Pin
OEM Authority: Textron Aviation (Cessna)
Material: High-Strength Alloy Steel (e.g., 4140 or 4340, per OEM specification).
Finish: Cadmium Plated.
Dimensions: Precision-ground diameter and length per Textron Drawing 0511771.
Governing Specification: Textron Aviation Engineering Drawing 0511771.
Aircraft Compatibility
This OEM torque link pin is the standard component for the nose landing gear on a vast fleet of Cessna's most popular single-engine aircraft.
Primary Textron Aviation Platforms:
Cessna 150, 152
Cessna 172, 177
Cessna 182
Cessna 206, 207
Cessna 210
Note: Verification of applicability is the absolute responsibility of the installer. The aircraft's current Illustrated Parts Catalog (IPC) for its specific serial number is the final authority for confirming part number eligibility.
Applications
Sole Application: To serve as the upper or lower pivot pin connecting the arms of the nose landing gear torque link (scissors) assembly on specified Cessna aircraft.
Why Choose 0511771-8?
The failure of a nose gear torque link pin can lead to a complete loss of directional control on the ground and the likely collapse of the nose gear. Only the genuine Textron OEM 0511771-8 is guaranteed to be made from the correct certified steel alloy and to have undergone the precise heat treatment process required to achieve the necessary balance of shear strength and fracture toughness. A generic or improperly machined pin made from a lesser material or with an incorrect heat treatment could fail without warning under the normal operational stresses of landing and taxiing, with catastrophic results.
The 0511771-8 pin is an excellent example of a component designed to operate in double shear. The pin passes through the lug of the upper torque link, then the lug of the lower torque link, and is supported on both sides. When a torsional load is applied to the nose wheel, it is transmitted through the linkage as a shear force that attempts to "cut" the pin at two distinct planes—one at the interface of each torque link arm. This loading condition is highly efficient and subjects the pin to pure shear stress with minimal bending moment. For this reason, the pin's material is chosen not just for its ultimate shear strength, but for its fracture toughness. The heat treatment process is designed to create a fine-grained, tempered martensitic microstructure. This provides the necessary high strength to resist yielding under normal loads, but also the toughness to absorb the energy of sudden, high-impact shock loads (such as hitting a bump while taxiing) and resist the initiation and propagation of a fatigue crack, preventing a sudden, brittle fracture.
Note: This is a flight-critical, on-condition landing gear component. It must be regularly inspected for wear, corrosion, and scoring in accordance with the aircraft maintenance manual. The installation must be performed by a certified A&P mechanic. The pin must be installed with the correct castellated nut and a new cotter pin, which must be secured properly. The entire torque link assembly should be checked for excessive play after installation.
Documentation
All technical data, installation procedures, and wear limits for the 0511771-8 pin are proprietary to Textron Aviation. This information is contained within the official Maintenance Manual and Illustrated Parts Catalog for the applicable aircraft model. No public-facing documentation is available.