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NAS72-9E006 – Aerospace High-Precision Press-Fit Bushing
Available now on the Airparts.aero Marketplace.
The NAS72-9E006 is a high-precision structural bushing manufactured to the National Aerospace Standard (NAS). As a critical element in airframe mechanical assemblies, this press-fit bushing is designed to provide a hard, wear-resistant interface for bolts and pins within aluminum or composite structures. By serving as a sacrificial wear surface, the NAS72-9E006 protects the primary airframe structure from "egging" or elongation caused by cyclic loading and vibration, allowing for easier maintenance and extending the fatigue life of major components.
Fabricated from high-strength alloy steel, the NAS72-9E006 is engineered to withstand significant radial loads while maintaining precise internal tolerances. The "E" designation typically indicates a specific material or finish requirement, often a cadmium-plated finish to prevent galvanic corrosion and hydrogen embrittlement when installed in dissimilar metal assemblies. This bushing is commonly found in flight control surfaces, landing gear pivot points, and structural brackets where rotational or oscillating motion requires a durable, low-friction bearing surface. For the A&P/IA mechanic, the NAS72-9E006 represents a standardized, certified solution for restoring or maintaining structural joint integrity.
Key Features
High-Strength Alloy Construction: Manufactured from heat-treated alloy steel (typically 4130 or 8630) to provide superior compressive 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 during high-frequency vibration.
Corrosion-Resistant Finish: Treated with cadmium plating (per QQ-P-416) or equivalent protective coating to mitigate intergranular corrosion at the structural interface.
Close-Tolerance Internal Diameter: Features a micro-finished bore designed to match the specific clearance requirements of NAS and MS series bolts.
Structural Sacrificial Design: Protects expensive airframe castings and skins from wear, shifting the mechanical stress to a replaceable, high-strength component.
Technical Specifications
Part Number: NAS72-9E006
Component Type: Plain Press-Fit Bushing (Headed or Headless based on dash code)
Manufacturer: Various FAA-PMA Approved Manufacturers
Material: High-Strength Alloy Steel (Heat-treated per AMS specifications)
Finish: Cadmium Plate, Type II, Class 2 (Yellow Dichromate)
Inside Diameter (ID): Refer to NAS72-9 dimensional table (typically 9/16" nominal or specific dash size)
Outside Diameter (OD): Precision-ground for interference fit (Refer to OEM specification)
Length: Specifically defined by the E006 suffix (0.375" or specific configuration)
Governing Specifications: NAS72 Standard
Certification: FAA-PMA / OEM Standard Hardware
Aircraft Compatibility
Boeing 737, 747, and 757 Series
Airbus A320 and A330 Families
Gulfstream GIV and GV Series
McDonnell Douglas MD-80/90 Series
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 Hinges: Providing a wear-resistant pivot for aileron, elevator, and rudder linkages.
Landing Gear Trunnions: Securing secondary hydraulic and mechanical linkages.
Engine Pylon Brackets: Isolating high-strength fasteners from aluminum mounting structures.
Why Choose NAS72-9E006?
Utilizing the genuine NAS72-9E006 is essential for maintaining the Structural Clamping Integrity of a joint. In aerospace engineering, using non-certified or "industrial grade" bushings can lead to catastrophic joint failure; industrial bushings often lack the precise interfacial friction and surface hardness required to prevent "fretting" in a high-vibration airframe. The NAS72-9E006 ensures that the 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 NAS72-9E006 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 (often 4130 chromoly) is precipitation-hardened to reach a specific Rockwell C 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 NAS72-9E006 is a structural component. Installation requires a precise "interference fit" as specified in the Structural Repair Manual (SRM); this often requires chilling the bushing in liquid nitrogen or "dry ice" and/or heating the housing to avoid galling the bore during installation. Any bushing showing signs of scoring, pitting, or migration must be replaced. Installation must be performed by a certified A&P mechanic.
