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NAS72-9E008 – Aerospace High-Precision Structural Bushing
Available now on the Airparts.aero Marketplace.
The NAS72-9E008 is a high-precision structural bushing manufactured to the National Aerospace Standard (NAS), designed for use in critical airframe mechanical assemblies. This press-fit component serves as a hard, wear-resistant interface for bolts, pins, and shafts within aluminum or composite structures. By acting as a sacrificial wear surface, the NAS72-9E008 protects the primary airframe structure from "egging," elongation, and localized deformation caused by cyclic loading and high-frequency vibration, thereby extending the fatigue life of major assemblies.
Fabricated from high-strength alloy steel, the NAS72-9E008 is engineered to withstand significant radial loads while maintaining exacting internal tolerances. The "E" designation indicates a specific material and finish standard—typically a cadmium-plated finish—providing essential galvanic corrosion protection and a stabilized friction coefficient for installation. This bushing is a staple in flight control hinges, landing gear pivots, and engine pylon brackets where metal-on-metal rotational or oscillating motion occurs. For the A&P/IA mechanic, the NAS72-9E008 represents a standardized, certified solution for restoring structural joint integrity during overhaul or repair.
Key Features
High-Strength Alloy Construction: Manufactured from heat-treated alloy steel (typically 4130 or 8630 chromoly) to ensure superior compressive yield strength and surface hardness.
Precision Press-Fit Geometry: Engineered with a controlled interference fit allowance to ensure the bushing remains securely seated in the bore under extreme vibration and G-loads.
Corrosion-Resistant Finish: Treated with Cadmium Plate, Type II (Yellow Dichromate) per QQ-P-416 to prevent intergranular corrosion at the structural interface between dissimilar metals.
Structural Sacrificial Design: Designed to absorb mechanical wear that would otherwise compromise expensive airframe castings, spars, or skins.
Concentricity and Micro-Finish: Features a precision-ground internal diameter with a micro-finish that minimizes friction and prevents "stiction" in mechanical linkages.
Technical Specifications
Part Number: NAS72-9E008
Component Type: Plain Press-Fit Bushing (Headed or Headless based on configuration)
Manufacturer: Various FAA-PMA Approved Manufacturers
Material: High-Strength Alloy Steel (Heat-treated per AMS specifications)
Finish: Cadmium Plate, Type II, Class 2 (Yellow)
Inside Diameter (ID): 0.5625 inches (9/16" nominal) – Refer to NAS72 dimensional table for exact tolerances.
Outside Diameter (OD): Precision-ground for interference fit (Typically 0.0005" to 0.0015" over bore size).
Length: Specifically defined by the -008 suffix (Typically 0.500 inches).
Governing Specifications: NAS72 Standard
Certification: FAA-PMA / OEM Standard Hardware
Aircraft Compatibility
Boeing 737, 747, 757, and 767 Series
Airbus A320 and A330 Families
Gulfstream GIV and GV Series
Bombardier Challenger and Global Express
Note: NAS72 bushings are universal structural parts. Always consult the Illustrated Parts Catalog (IPC) or Structural Repair Manual (SRM) to verify the exact dash number and material requirement for your specific station.
Applications
Flight Control Linkages: Providing a durable pivot point for aileron, elevator, and rudder hinges.
Landing Gear Interfaces: Securing secondary hydraulic and mechanical linkages in the nose and main gear bays.
Engine Pylon Mounts: Isolating high-strength fasteners from the aluminum pylon or wing spar structure.
Why Choose NAS72-9E008?
Utilizing the genuine NAS72-9E008 is essential for maintaining the Structural Clamping Integrity of a joint. In aerospace engineering, using non-certified "industrial grade" bushings introduces the risk of catastrophic failure. Industrial bushings often lack the precise interfacial friction and Rockwell hardness required to prevent "fretting"—microscopic surface welding—in high-vibration airframes. The NAS72-9E008 ensures that bearing stress is distributed as the designers intended, preventing localized cracking in the primary structure and ensuring the aircraft remains in its certified configuration.
The NAS72-9E008 functions on the principle of Interference Fit Load Transfer. When the bushing is pressed into a bore with a calculated negative allowance, it creates a state of Residual Compressive Stress around the hole. This is a critical engineering technique used to improve the Fatigue Life of the airframe, as it offsets the tensile stresses encountered during flight loading.
From a materials science perspective, the alloy steel is precipitation-hardened to reach a specific hardness, ensuring that the Yield Strength of the bushing is significantly higher than that of the surrounding aluminum structure. This prevents the "pounding" effect where the bolt shank would otherwise deform the softer airframe material. The Cadmium plating acts not only as a corrosion barrier but also as a Solid-Film Lubricant, preventing the microscopic "welding" known as Fretting that occurs at the interface of two metal surfaces subject to high-frequency oscillation.
Note: The NAS72-9E008 is a structural component. Installation requires a precise "interference fit" as specified in the Structural Repair Manual (SRM). This often requires "shrink-fitting" the bushing using dry ice or liquid nitrogen to avoid galling the bore during installation. Any bushing showing signs of migration, scoring, or pitting must be replaced. Installation must be performed by a certified A&P mechanic.
