C-40257 - Textron Aviation OEM Propeller Brush Block

C-40257 – Textron Aviation OEM Propeller Brush Block

Available now on the Airparts.aero Marketplace.

Overview

The Textron Aviation C-40257 is a genuine OEM propeller brush block, a flight-critical component of the electro-thermal propeller de-icing system on a wide range of Beechcraft King Air and other high-performance aircraft. This assembly is designed to safely and reliably transfer electrical current from the stationary airframe to the rotating propeller slip ring assembly. This current is then channeled to the propeller de-ice boots to generate the heat required to shed ice. As a genuine Textron OEM part, it guarantees the correct materials, spring tension, and electrical characteristics required for the safe and effective operation of the aircraft's ice protection system.

Key Features

• Reliable Current Transfer: Houses multiple carbon brushes, each held against the propeller slip ring by a constant-force spring. This design ensures a continuous, low-resistance electrical connection to the rotating propeller assembly, which is essential for proper de-ice boot heating.
• High-Quality Carbon Brushes: The carbon brushes are made from a specialized, conductive carbon-graphite composite. This material is chosen for its excellent electrical conductivity and its inherent lubricity, which minimizes wear on the expensive propeller slip rings.
• Durable Insulating Block: The main body of the assembly is molded from a high-dielectric strength, temperature-resistant phenolic or similar composite material. This provides a robust, insulated housing that securely holds the brushes and prevents electrical shorting to the engine nose case.
• Constant-Force Springs: Each brush is backed by a precision-calibrated spring. This spring ensures that the brush maintains a consistent and correct pressure against the slip ring, even as the brush wears down over time, guaranteeing a reliable electrical connection.
• Genuine Textron OEM Part: As a genuine factory component, it guarantees perfect fitment, correct brush material, and the precise spring tension required for the de-icing system to function as certified.

Technical Specifications

• Part Number: C-40257
• Component Type: Propeller De-Ice Brush Block Assembly
• Brush Material: Conductive Carbon-Graphite Composite
• Block Material: High-Dielectric Strength Phenolic Composite
• Primary Function: Transfers electrical current from the airframe to the propeller slip ring.
• Certification: FAA Production Approval

Aircraft Compatibility

The C-40257 is a standard brush block used in the propeller de-ice systems of many of the world's most popular turboprop and high-performance piston twin aircraft.

• Primary Aircraft Models:
  • Beechcraft King Air: 90, 100, 200 Series
  • Beechcraft Baron: 58P, 58TC
  • Beechcraft Duke
  • Cessna: 340, 414, 421, 425
  • Piper: Cheyenne
  • And many other aircraft equipped with electro-thermal propeller de-ice systems.

Applications

The C-40257 is a critical component for safe flight in icing conditions:

• Propeller Ice Protection: The key stationary component that delivers the electrical power to the rotating propeller de-ice boots.
• Scheduled Maintenance: Brushes are wear items and are a mandatory inspection item. The brush block must be inspected regularly for brush length, spring condition, and for any signs of arcing or contamination.
• System Troubleshooting: A primary component to inspect when diagnosing an inoperative or intermittently functioning propeller de-ice system.

Why Choose C-40257?

A functioning propeller de-ice system is mandatory for any aircraft certified for Flight Into Known Icing (FIKI). Failure of the brush block to transfer current can render the entire system useless, creating a severe flight hazard. Using a genuine Textron Aviation C-40257 OEM brush block is the only way to ensure the part has the correct, certified brush material to prevent excessive wear on the slip rings and the correct spring tension for a reliable, arc-free connection. For a flight-critical safety system, there is no substitute for genuine OEM parts.

Order Your C-40257 Brush Blocks Now

Ensure the reliability of your aircraft's ice protection system with genuine, factory-certified OEM components. Visit Airparts.aero to order your Textron Aviation C-40257 propeller brush blocks today.

The C-40257 brush block is a critical interface between the aircraft's static and rotating systems. Electrical current from the de-ice timer/controller is routed to terminals on the brush block. This current flows through the pigtail leads into the carbon brushes. The constant pressure from the springs ensures the brushes are in firm contact with the concentric, conductive slip rings that are rotating with the propeller. The current is transferred to the slip rings, and from there, it is routed via wires along the propeller blades to the de-ice boots. The carbon-graphite material of the brushes is specifically designed to deposit a thin, conductive graphite film onto the slip rings, which reduces both mechanical friction and electrical resistance, allowing for efficient current transfer with minimal arcing or wear.

Note: This is a flight-critical ice protection system component. Installation and inspection must be performed by a certified A&P mechanic in accordance with the current aircraft maintenance manual. Brushes must be inspected for minimum length and the slip rings must be clean and in good condition for proper operation.

Replaces part number C40257