MS9574-05 - Textron Aviation OEM Drilled Fillister Head Machine Screw

MS9574-05 – Textron Aviation OEM Drilled Fillister Head Machine Screw

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The MS9574-05 is a genuine Textron Aviation OEM, flight-critical machine screw manufactured in strict accordance with Military Standard MS9574. This fastener is engineered for high-strength structural applications where positive locking is mandatory. It is defined by its tall, cylindrical fillister head, which provides a deep slot for high torque application, and its head being drilled with three holes for the installation of safety wire.

Fabricated from high-strength, heat-treated alloy steel and finished with a protective cadmium plating, the MS9574-05 is designed for use in areas of high vibration, such as firewall-forward or in critical instrument and component mountings. The combination of high tensile strength (125 KSI) and a positive locking feature makes this a fundamental component for ensuring that critical joints remain secure under all operating conditions.

Key Features

• Genuine Textron Aviation OEM Part: Guarantees adherence to the stringent material, heat treatment, and dimensional tolerances required by Textron (Cessna, Beechcraft).

• Drilled Head for Positive Locking: The defining feature of the MS9574 standard, the drilled head, allows for the use of safety wire (e.g., MS20995), providing a positive mechanical lock that physically prevents the screw from loosening.

• Fillister Head Design: The tall, cylindrical head with a deep slot is engineered to allow for high driving torque during installation.

• Heat-Treated Alloy Steel Construction: Manufactured from high-grade alloy steel (e.g., SAE 4140 or 8740) and heat-treated to a minimum tensile strength of 125,000 PSI, providing excellent strength.

• Rolled Threads for Superior Fatigue Resistance: Features UNC-3A threads that are cold-rolled, not cut, a process that induces compressive residual stresses at the thread root, dramatically increasing resistance to fatigue failure.

• Cadmium Plated for Corrosion Protection: Coated with a sacrificial layer of cadmium per QQ-P-416, providing excellent, long-lasting corrosion resistance in the harsh aviation environment.

Technical Specifications

• Part Number: MS9574-05

• Component Type: Drilled Fillister Head Machine Screw

• Governing Specification: MS9574 (Military Standard)

• OEM Manufacturer: Textron Aviation

• Material: Alloy Steel (e.g., SAE 4140 / 8740), Heat Treated

• Finish: Cadmium Plated per QQ-P-416, Type II, Class 3

• Dimensions:

  • Thread: 6-32 UNC-3A

  • Length (Nominal, under head to end): 5/16 inch (0.3125 in)

• Head Style: Fillister (Drilled)

• Drive Type: Slotted

• Minimum Tensile Strength: 125,000 PSI

Aircraft Compatibility

The MS9574-05 is a standard hardware component used universally across all categories of certified aircraft from all major manufacturers, including Textron Aviation (Cessna, Beechcraft), Piper, and others. It is specified in any application requiring a heat-treated, #6-32 drilled fillister head screw of this length.

Crucial Note: The correct part number for a specific application must be verified against the aircraft's Illustrated Parts Catalog (IPC) or maintenance manual.

Applications

The MS9574-05 is designed for any joint subjected to vibration where a positive lock is required. Common applications include:

• Securing instruments and avionic components to the instrument panel.

• Fastening brackets, supports, and clips within the airframe, engine compartment, and on accessories.

• Attaching component covers and access panels.

• Used in any joint where the maintenance manual explicitly calls for the fastener to be secured with safety wire.

Why Choose MS9574-05?

Choosing a genuine MS9574-05, as specified by Textron Aviation, is a flight-critical decision. Commercial or "hardware store" screws lack the certified material traceability, the mandatory heat treatment, and the superior fatigue life of rolled threads. The failure of a fastener due to vibration or improper strength can lead to component detachment, system failure, or inaccurate instrument readings. The drilled head of the MS9574 is not optional; it is a design feature for positive locking, a fundamental principle of aviation safety. The MS standard is the only guarantee of this quality and safety.

The engineering principle behind the MS9574-05's drilled head is positive mechanical locking. This stands in contrast to friction-based locking mechanisms (e.g., lock washers, prevailing torque nuts) which merely increase the resistance to loosening. Positive locking provides a physical obstruction that makes rotation impossible. By threading safety wire (e.g., MS20995) through the head and anchoring it to another fastener or a fixed point, a mechanically redundant load path is created. This wire physically prevents the screw from rotating counter-clockwise (loosening) due to high-frequency vibration or thermal cycling. This is a non-negotiable safety requirement in many airframe and firewall-forward applications where a loosened fastener could lead to catastrophic failure. The fastener's high fatigue life is further enhanced by rolled threads, a cold-working process that induces compressive residual stresses at the thread root, making it highly resistant to the initiation of fatigue cracks.

Note: This is a flight-critical structural fastener. It is designed to be secured using safety wire. It MUST be replaced with a part of the same specification. Substitution with an undrilled screw (e.g., AN502) or a commercial-grade fastener is not permissible in this application. Torquing and safety wire procedures must be performed by a certified A&P mechanic in strict accordance with standard maintenance practices (e.g., AC 43.13-1B) and the applicable maintenance manual.

Documentation

The definitive technical requirements for this component are detailed in Military Standard MS9574. These proprietary documents must be sourced directly from the relevant standards organizations for complete engineering specifications.