3070800-46 - Honeywell Aerospace Turbine Engine Main Fuel Control Assembly

3070800-46 – Honeywell Aerospace Main Fuel Control (MFC) Assembly

Available now through the AirParts Aero marketplace.

Overview Section

The Honeywell 3070800-46 is a state-of-the-art Main Fuel Control (MFC), representing one of the most advanced iterations of the hydro-mechanical fuel control family for the Honeywell TFE731 turbofan series. The -46 dash number is specifically engineered for the high-performance TFE731-40 and -60 engine variants, which power the latest generation of mid-to-large business jets.

This assembly acts as the engine's "primary computer," metering fuel with extreme precision by balancing pilot input (Power Lever Angle) against real-time atmospheric data: Compressor Discharge Pressure ($P_3$) and Inlet Temperature ($T_2$). The -46 variant incorporates the latest metallurgical and pneumatic refinements to handle the higher thrust outputs and increased thermal loads of modern geared turbofan operations.

Key Features Section

• Precision Transient Management: Features a refined internal 3D cam profile that ensures smooth, "bump-free" engine acceleration even at high-density altitudes, providing superior surge protection.

• Optimized for High-Thrust Variants: Calibrated specifically for the increased airflow and pressure ratios of the -40 and -60 series engines, ensuring peak efficiency during high-speed cruise.

• Advanced Bellows Technology: Utilizes high-durability pneumatic bellows designed to provide repeatable, accurate sensing of $P_3$ air, reducing throttle hysteresis and "RPM hunting."

• Corrosion-Resistant Internal Components: The -46 often includes the latest surface treatments on internal valves to mitigate the effects of "stiction" caused by varied fuel qualities and environmental contaminants.

• Integrated Mechanical Governor: Provides fail-safe $N_2$ overspeed protection, physically limiting fuel flow should the engine attempt to exceed structural RPM limits.

• Superior Thermal Stability: The ruggedized cast housing and internal seals are designed to maintain calibration accuracy across an extreme temperature range, from $-65°F$ to $+350°F$.

Technical Specifications Section

Aircraft Compatibility Section

The 3070800-46 is a critical component for the following modern business jets in the AirParts Aero inventory:

• Dassault Falcon 900EX / 900LX / 900DX: Core fuel management for the triple-engine TFE731-60 configuration.

• Dassault Falcon 50EX: Utilized in the upgraded -40 series engine installations for enhanced climb performance.

• Gulfstream G150: Essential for the reliability of the TFE731-40AR engines on this high-speed transcontinental jet.

• Cessna Citation VII (Upgraded): Found in late-model variants or those upgraded with enhanced fuel management kits.

Technical Applications & Safety

The MFC is a closed-loop feedback system. It continuously compares the pilot's requested power against the actual work the engine is doing ($P_3$ pressure). If the $P_3$ sensing line is restricted by carbon or moisture, the 3070800-46 will sense an artificial "low air" condition and limit fuel, preventing the engine from reaching takeoff power.

Safety Warning: Installation requires a mandatory "Part Power Trim" check. This procedure synchronizes the MFC with the engine's specific Interstage Turbine Temperature (ITT) curves. Failure to properly rig the 3070800-46 can result in "Hot Starts" or over-temperature events that can cause permanent, multi-million dollar damage to the turbine's hot section during the first application of takeoff power.

Technical Engineering Insight

The engineering value of the 3070800-46 lies in its Signal Dampening Architecture. In high-pressure engines like the TFE731-60, $P_3$ air can be highly turbulent. The -46 variant uses precision-drilled orifices to dampen these pressure "pulses" before they reach the sensing bellows. This ensures the engine provides a rock-steady power setting even in turbulent air, significantly improving the precision of autothrottle systems where installed.

*** THIS ITEM REPLACES HONEYWELL PART NUMBER: 3070800-36

By choosing a certified 3070800-46 through AirParts Aero, you ensure the unit has been bench-tested to verify its Acceleration and Deceleration Schedules against the Honeywell master curve, protecting the engine from surge-induced flameouts during critical flight maneuvers.

Installation & Maintenance Addendum

1. $P_3$ Air Filter: Always install a new $P_3$ air filter when installing the MFC. A dirty filter is the most common cause of "sluggish" engine response.

2. Drive Spline Integrity: Inspect the drive splines on the engine accessory gearbox for "red dust" (fretting). Apply the specified high-pressure lubricant to the 3070800-46 drive shaft to ensure longevity.

3. Preservation: If the unit is removed for storage, it must be filled with MIL-PRF-6081 light oil. If left dry, the internal steel bellows can corrode, leading to an "out-of-calibration" condition upon re-installation.