SL71973 - Superior Air Parts FAA-PMA Magneto Gasket

SL71973 – Superior Air Parts FAA-PMA Magneto Gasket (replaces Lycoming 71973)

Available now on the Airparts.aero Marketplace.

The Superior Air Parts SL71973 is a premium, FAA-PMA certified gasket, engineered as a direct replacement for the Lycoming OEM part number 71973. Manufactured by Superior Air Parts, a trusted leader in the FAA-PMA market, this component provides a flight-critical, leak-free seal between the magneto and the engine's accessory drive case. Its function is to reliably contain the hot, pressurized engine oil that lubricates the magneto drive gear, preventing leaks that can create a fire hazard in the engine compartment.

As an FAA-PMA approved part, the SL71973 has undergone a rigorous certification process to demonstrate that its material, design, and performance are equivalent to or superior than the original OEM component. It is precision-cut from an advanced, oil-resistant composite material designed to provide a durable and reliable seal throughout its service life, offering a dependable and cost-effective solution for engine and ignition system maintenance.

Key Features

• FAA-PMA Approved Replacement: Fully certified by the FAA as a safe and direct replacement for Lycoming P/N 71973, ensuring airworthiness and compliance.

• Meets or Exceeds OEM Specifications: Designed and manufactured to the highest standards, ensuring performance and durability that is equivalent or superior to the original component.

• Advanced Oil-Resistant Composite Material: Utilizes a modern, high-grade composite of cellulose fibers and a synthetic rubber binder, specifically formulated to resist degradation from hot engine oil and aviation fuels.

• Precision Die-Cut for a Perfect Fit: Guarantees a perfect match to the magneto and accessory case flanges, ensuring even clamping pressure and a reliable, leak-free seal.

• Cost-Effective, High-Quality Alternative: Provides a trusted, reliable, and economical option for replacing a mandatory-replacement wear item during engine maintenance.

Technical Specifications

• Part Number: SL71973

• Component Type: FAA-PMA Magneto Mounting Gasket

• Manufacturer: Superior Air Parts, Inc.

• Replaces: Lycoming P/N 71973

• Material: High-grade, oil-resistant cellulose fiber and synthetic rubber (Nitrile) composite.

• Application: Seals the standard two-bolt mounting flange of Bendix or Slick magnetos to the accessory case.

Engine Compatibility

The SL71973 is FAA-PMA approved for installation on the vast majority of direct-drive Lycoming engines where the Lycoming P/N 71973 is specified. Applicable engine families include, but are not limited to:

• O-235, O-320, IO-320, AEIO-320 Series

• O-360, IO-360, AEIO-360, TIO-360 Series

• O-540, IO-540, AEIO-540, TIO-540, LTIO-540 Series

Crucial Note: The official FAA-PMA supplement for SL71973 and the specific engine's Illustrated Parts Catalog (IPC) are the final authorities for verifying installation eligibility.

Fits the following engine models:

Applications

This gasket is a critical replacement part during major engine and ignition system maintenance.

• Complete Engine Overhaul

• 500-Hour Magneto Inspection and Repair

• Any maintenance requiring the removal or installation of a magneto.

Why Choose SL71973?

Choosing the Superior Air Parts SL71973 provides a certified, high-quality alternative from a leading and trusted manufacturer of aftermarket engine components. The FAA-PMA approval guarantees that the part is a safe and reliable substitute, often at a more competitive price point. A leaking magneto gasket is a common nuisance and a potential safety hazard. The SL71973 is made from a modern, durable composite material designed to hold a reliable seal, ensuring your engine's accessory case remains clean and free of oil leaks.

To gain FAA-PMA approval, the SL71973 must be manufactured from an engineered composite material that is at least equivalent to the original. This material utilizes a non-asbestos, cellulose fiber matrix to provide structural stability and resistance to extrusion under the clamping pressure of the mounting nuts. This fibrous matrix is then saturated and bonded under heat and pressure with a high-percentage Nitrile (NBR) elastomer. The Nitrile binder provides three critical properties that the fiber alone cannot: 1) Impermeability: It fills the microscopic voids within the fiber matrix, rendering the gasket impervious to the pressurized, low-viscosity engine oil. 2) Conformability: The rubber allows the gasket to flow and conform to any minor surface irregularities on the machined aluminum flanges of the magneto and accessory case, ensuring a complete seal. 3) Resilience: The elastomer gives the gasket the ability to maintain a constant sealing pressure (stress retention) even as the joint experiences minor movements due to the engine's vibration and thermal expansion cycles. This composite approach provides a vastly superior and more durable seal compared to a simple fiber or simple elastomer gasket alone.

Note: This is a single-use component. This gasket MUST be replaced with a new one every time a magneto is installed or reinstalled. Re-using a compressed gasket will result in an oil leak. The magneto and engine mounting surfaces must be perfectly clean, dry, and free of any old gasket material or sealant prior to installation. The magneto mounting nuts should be torqued evenly to the value specified in the engine maintenance manual.

Documentation

The definitive application and installation eligibility for this FAA-PMA component must be confirmed using the official FAA-PMA database and the Illustrated Parts Catalog (IPC) and maintenance manuals for the specific engine model.