68-450 - Textron Aviation Over Inflation Plug Seal for Citation and SkyCourier Aircraft

68-450 – Textron Aviation OEM Fusible Plug for Citation and SkyCourier Aircraft

Available now on the Airparts.aero Marketplace.

Overview

The 68-450 is a genuine OEM, flight-critical fusible plug, an essential safety device engineered for the wheel assemblies of high-performance Textron Aviation aircraft, including the Citation and SkyCourier series. Often referred to as an "over-temperature plug," this is not a standard seal but a thermally-activated pressure relief device. Its sole purpose is to prevent a catastrophic tire explosion by safely deflating the tire in the event of an extreme over-temperature condition, typically caused by a severe braking event. Manufactured by industry leaders like B.F. Goodrich (Collins Aerospace) to Textron's exact specifications, this component is fundamental to landing gear and operational safety.

Key Features

• Thermal Pressure Relief: The core of the plug contains a eutectic alloy with a precisely calibrated melting point. If the wheel assembly temperature rises to this critical point, the alloy melts and is expelled, creating a vent path for the nitrogen in the tire to be safely released.
• Prevents Catastrophic Tire Failure: In a maximum-energy rejected takeoff (RTO) or a prolonged, heavy braking event, brake temperatures can soar, potentially igniting the tire from the inside out. The fusible plug prevents this by deflating the tire before the auto-ignition temperature is reached.
• High-Strength Body Construction: The main body of the plug is machined from a high-quality brass or bronze alloy, providing the strength to contain normal tire pressures while ensuring excellent thermal conductivity to the eutectic core.
• Single-Use Safety Device: Engineered as a mandatory single-use component. Once activated by heat, the plug is destroyed and must be replaced. It is also recommended to replace all fusible plugs during a tire change.
• Genuine OEM Specification: As a genuine part specified by Textron Aviation, it guarantees the correct eutectic alloy melting point, material composition, and thread specifications required for the certified wheel assembly.

Technical Specifications

• Part Number: 68-450
• Component Type: Fusible Plug / Thermal Pressure Relief Device
• OEM Manufacturer (Typical): B.F. Goodrich / Collins Aerospace
• Body Material: Brass or Bronze Alloy
• Core Material: Eutectic Alloy with a precise melting temperature.
• Installation: Threads into dedicated ports on the aircraft wheel hub.
• Certification: FAA Production Approval

Aircraft Compatibility

The 68-450 fusible plug is a critical safety component for the wheel assemblies on various Textron Aviation jet and high-performance turboprop aircraft. It is imperative to consult the specific aircraft's Illustrated Parts Catalog (IPC) for final verification.

• Primary Aircraft Models:
  • Cessna Citation Series (various models)
  • Textron Aviation SkyCourier (Cessna 408)

Applicable Textron Aircraft

Click on aircraft model to view serial range in Shop by Model.

• Citation Latitude
• Citation Longitude
• Citation X+
• SkyCourier

List not comprehensive, may be applicable on other models.

Applications

The 68-450 is a non-operating safety device with a singular, critical function:

• Wheel & Tire Overheat Protection: Acts as the last line of defense against a thermally-induced tire explosion.
• Mandatory Maintenance Item: Fusible plugs must be inspected for security and signs of leakage at every tire change and are typically replaced as a complete set whenever a tire is replaced or the wheel is overhauled.

Why Choose 68-450?

The energy absorbed by the brakes during a rejected takeoff on a jet aircraft can be immense, generating enough heat to melt the aluminum wheel itself. A fusible plug is an elegant engineering solution that prevents this heat from causing a tire to explode, which would send high-velocity shrapnel across the ramp or runway, endangering personnel, other aircraft, and the airframe itself (especially wing-mounted engines). Using a genuine OEM-specified 68-450 is the only way to ensure the plug will activate at the correct, certified temperature, providing a critical layer of safety for the aircraft and ground crew

Order Your 68-450 Fusible Plugs Now

Ensure the ultimate safety of your aircraft's wheel and brake assemblies with genuine, certified components. Visit Airparts.aero to order your 68-450 fusible plugs today.

The 68-450 fusible plug operates on a simple principle of phase-change physics. A eutectic alloy is a mixture of metals whose combined melting point is lower than that of any of its individual components. This allows engineers to create an alloy that melts at a very specific and predictable temperature. The plug is installed in direct thermal contact with the wheel hub, the area that heats up most rapidly during braking. When the wheel's temperature reaches the eutectic alloy's melting point (e.g., 390°F / 199°C), the solid alloy core liquefies almost instantly. The high-pressure nitrogen in the tire then blows the molten alloy out of the plug body, creating a clear vent path. This controlled deflation is infinitely safer than an uncontrolled, explosive decomposition of the tire structure.

Note: This is a flight-critical safety component. Installation must be performed by a certified A&P mechanic or at a certified wheel and brake overhaul facility. Fusible plugs must be torqued to the value specified in the component maintenance manual. It is standard practice to replace all fusible plugs on a wheel at the same time.