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2611202-2 – Honeywell Aerospace Multiple Disc Brake Assembly (Boeing 777)
Available now on the Airparts.aero Marketplace.
The Honeywell 2611202-2 is a high-performance, flight-critical multiple disc brake assembly specifically engineered for the Boeing 777-200 and 777-300 series aircraft. As a primary component of the Main Landing Gear (MLG), this assembly utilizes advanced Carbon-Carbon friction technology to provide the massive stopping power required for a wide-body aircraft with a Maximum Takeoff Weight (MTOW) exceeding 600,000 lbs. The 2611202-2 is designed to absorb and dissipate enormous amounts of kinetic energy during landing and Rejected Takeoff (RTO) scenarios, where temperatures within the brake stack can momentarily exceed $2,000^\circ\text{F}$ ($1,093^\circ\text{C}$).
Constructed with a lightweight yet high-strength forged aluminum housing and a series of alternating carbon stators and rotors, the 2611202-2 represents the pinnacle of "Heat Sink" engineering. This specific Honeywell configuration is optimized for long "Tire-Life" and extended intervals between overhauls, utilizing a high-pressure hydraulic piston system that ensures even clamping force across the entire disc stack, preventing "brake fade" and uneven wear.
Key Features
Advanced Carbon-Carbon Friction Material: Offers a superior strength-to-weight ratio compared to steel brakes, significantly reducing the aircraft's "Empty Weight" and improving fuel efficiency.
Multiple Disc "Stack" Architecture: Utilizes a series of rotating discs (rotors) keyed to the wheel and stationary discs (stators) keyed to the torque tube, providing a massive total friction surface area.
High-Pressure Hydraulic Actuation: Equipped with multiple independent hydraulic pistons that provide redundant clamping force, ensuring continued braking capability even in the event of a partial hydraulic system failure.
Integrated Wear Indicator Pins: Features precision-calibrated "visual" pins that allow ground crews to quickly assess the remaining life of the carbon stack without disassembly.
Rapid Heat Rejection: The open-architecture torque tube and heat-shielding are designed to maximize convective cooling, reducing "Turn-Around Time" (TAT) at the gate.
Technical Specifications
Part Number: 2611202-2
Manufacturer: Honeywell Aerospace (Aircraft Landing Systems)
Component Type: Multiple Disc Main Landing Gear (MLG) Brake
Aircraft Application: Boeing 777-200, 777-200ER, 777-300
Friction Material: Carbon-Carbon Composite
Operating Fluid: Skydrol LD-4 / Skydrol 5 (Phosphate Ester)
Actuation Type: Hydraulic Piston (Multiple)
Certification: FAA-PMA / TSO-C26 (Boeing Approved)
Aircraft Compatibility
Boeing 777-200 Series: Including the ER (Extended Range) variants.
Boeing 777-300: (Non-ER standard variants; verify per IPC).
Note: Brake assemblies are matched to specific wheel part numbers. Consult the Boeing 777 Illustrated Parts Catalog (IPC) Section 32-41 to ensure the 2611202-2 is compatible with your current wheel and tire assembly.
Applications
The 2611202-2 is utilized for High-Energy Kinetic Deceleration. Its primary roles include:
Normal Landing Operations: Converting the aircraft's forward velocity into thermal energy during touchdown and rollout.
Rejected Takeoff (RTO): Providing the emergency stopping force required to halt a fully-fueled aircraft at V1 speeds.
Static Holding: Maintaining the aircraft in position during high-power engine run-ups or while parked at the gate.
Why Choose 2611202-2?
Choosing the genuine Honeywell 2611202-2 ensures the Thermal Integrity of the landing gear system. Carbon brakes have a unique property: their friction coefficient actually improves as they get hot, unlike steel brakes which can "glaze" and lose effectiveness. The 2611202-2 is specifically balanced to prevent Brake Induced Vibration (BIV), which can cause structural fatigue in the landing gear struts. Furthermore, Honeywell’s carbon formula is designed to resist "catalytic oxidation" from runway de-icing chemicals, significantly extending the life of the brake stack.
The 2611202-2 operates on the principle of Kinetic Energy Dissipation via the Work-Energy Theorem. For a Boeing 777 landing at $140\text{ knots}$, the kinetic energy ($E_k = \frac{1}{2}mv^2$) is massive. The brake assembly must convert this energy into heat through mechanical friction. The Carbon-Carbon discs are ideal because they possess a high Specific Heat Capacity and do not lose structural rigidity at high temperatures. The "Multiple Disc" design increases the friction surface area without increasing the diameter of the wheel, allowing for a compact yet powerful braking solution. The hydraulic pistons apply a clamping force ($F$) that is distributed across the "friction stack," creating a torque that opposes the wheel's rotation.
Note: This is a flight-critical, heavy component. Installation must be performed by a certified A&P/AME at a Part 145 repair station. Prior to installation, the hydraulic lines must be bled to remove all air. The carbon stack must be inspected for "chipping" or "oxidation." This assembly is subject to "Bedding-In" procedures as defined in the Boeing 777 Aircraft Maintenance Manual (AMM). Always use a calibrated torque wrench for the axle nut and mounting bolts.
