3026652 - Pratt & Whitney Canada PT6A Carbon Face Shaft Seal

3026652 – Pratt & Whitney Canada PT6A Carbon Face Shaft Seal

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The Pratt & Whitney Canada (P&WC) 3026652 is a genuine OEM, flight-critical carbon face seal, an essential component of the bearing compartment sealing system in the legendary PT6A series of turboprop engines. This is not a simple seal; it is a high-precision, pressure-activated mechanical device engineered to operate flawlessly under the extreme temperatures, pressures, and rotational speeds found in the core of a turbine engine. Its primary function is to create a dynamic seal between a rotating shaft and the stationary bearing housing, effectively containing lubricating oil within the bearing compartment while preventing high-pressure bleed air from entering.

The heart of the 3026652 is a stator ring fabricated from a proprietary, high-density carbon-graphite composite. This advanced material is selected for its exceptional thermal stability, chemical inertness to synthetic turbine oils, and most importantly, its self-lubricating properties. The seal's performance is fundamental to engine efficiency, oil consumption control, and the prevention of catastrophic oil leaks or oil coking in the turbine section.

Key Features

• Genuine Pratt & Whitney Canada OEM Part: The only component guaranteed to meet the exacting material, dimensional, and surface finish specifications required for a safe and reliable seal in a PT6A engine.

• High-Purity Carbon-Graphite Stator: The self-lubricating carbon ring is engineered to run against a hardened, rotating seal seat with an extremely low coefficient of friction, ensuring minimal wear over a long service life.

• Pressure-Activated Sealing Design: Utilizes engine bleed air pressure to provide the primary sealing force, creating a highly effective and responsive seal that adapts to changing engine power settings.

• Withstands Extreme Turbine Temperatures: The carbon-graphite material maintains its dimensional stability and sealing integrity at the very high operating temperatures of the engine's gas path.

• Precision-Lapped Sealing Face: The contact face of the carbon ring is lapped to a flatness measured in millionths of an inch (light bands), a requirement for establishing the necessary hydrodynamic air film for proper sealing.

Technical Specifications

• Part Number: 3026652

• Component Type: Carbon Face Shaft Seal (Stator Element)

• OEM Manufacturer: Pratt & Whitney Canada (P&WC)

• Engine Application: Pratt & Whitney Canada PT6A Series Turboprop Engines.

• Material: High-Density, Self-Lubricating Carbon-Graphite Composite.

• Sealing Mechanism: Pressure-Balanced Mechanical Face Seal.

Engine Compatibility

The 3026652 is a critical seal used in various bearing compartment locations across a wide range of Pratt & Whitney Canada PT6A engine models, including many of the most common variants installed on business, agricultural, and utility aircraft.

Crucial Note: The specific engine model, serial number, and location (e.g., #1, #2, #3 bearing) must be checked against the latest revision of the official P&WC Illustrated Parts Catalogue (IPC) to ensure correct part number applicability. The engine IPC is the final authority.

Applications

This carbon seal is a mandatory replacement item during any major engine work that involves accessing the main bearing compartments.

• Complete Engine Overhaul

• Hot Section Inspection and Repair

• Repair of the engine's gas generator or power turbine sections.

• Troubleshooting and repair of oil consumption or internal oil leak issues.

Why Choose 3026652?

Choosing a genuine P&WC 3026652 is an absolute necessity for the airworthiness and reliability of a PT6A engine. The engineering of a turbine engine carbon seal is extraordinarily precise. The flatness of the sealing face, the porosity of the carbon, and the balance of pressures that allow it to function are all critical. A non-genuine part risks using an inferior grade of carbon that could wear or crack prematurely, or it may lack the required dimensional precision. The failure of a main shaft seal can lead to a catastrophic in-flight oil loss, an engine fire, or severe internal engine damage. There is no substitute for the proven, certified engineering of a genuine Pratt & Whitney Canada part.

The 3026652 operates as a pressure-balanced hydrodynamic gas seal. Its function is a delicate equilibrium of forces. A light mechanical spring provides an initial closing force, seating the stationary carbon stator against the rotating seal seat during engine startup and shutdown. Once the engine is running, high-pressure P3 bleed air is ported to the back of the carbon seal's carrier, providing a powerful pneumatic closing force that is proportional to engine power. However, the seal is also "pressure balanced"—a small, precisely engineered portion of this high-pressure air is allowed to migrate across the seal face. This creates a small opening force that counteracts the primary closing force, preventing the seal faces from being crushed together and creating destructive friction. This intricate balance of forces causes the carbon ring to "fly" on a microscopic air-film, just nanometers away from the rotating seat. This gas film lubrication is what allows the seal to operate at extremely high surface speeds and temperatures with negligible wear, while maintaining a precisely controlled (and very low) leak rate that acts as a buffer, preventing oil from migrating out of the bearing sump.

Note: This is a flight-critical, precision internal engine component. The carbon element is extremely brittle and MUST be handled with extreme care and immaculate cleanliness to prevent chipping, cracking, or contamination of the lapped sealing face. Touching the lapped face with bare hands is forbidden. Installation constitutes a major engine repair and must be performed by a certified turbine engine technician in a clean-room environment, in strict accordance with the Pratt & Whitney Canada overhaul and maintenance manuals.

Documentation

The definitive part number applicability and all installation procedures are detailed in the applicable Pratt & Whitney Canada PT6A Series Illustrated Parts Catalogue (IPC) and Overhaul Manuals for the specific engine model.