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3883240-7 – Honeywell OEM Fuel Control Assembly Unit
Available now on the Airparts.aero Marketplace.
Overview
The Honeywell 3883240-7 is a flight-critical, OEM Fuel Control Unit (FCU), the primary hydromechanical "brain" for the highly successful Honeywell GTCP36 series of Auxiliary Power Units (APUs). This is not a simple fuel valve; it is a complex and sophisticated assembly that precisely meters fuel flow to the APU's combustor. The 3883240-7 FCU is responsible for managing the entire operational sequence of the APU, from the initial start cycle and acceleration to stable, governed speed operation and shutdown. It ensures the APU operates at its optimal efficiency while protecting it from damaging over-temperature, over-speed, and surge conditions.
As a genuine Honeywell component, this FCU is the factory-certified standard, guaranteeing the performance, reliability, and safety required for the APUs on a wide range of market-leading business jets. Its flawless operation is fundamental to the dispatch reliability of the aircraft.
Key Features
Hydromechanical Fuel Metering: At its core is a precision hydromechanical computing section. It uses a series of three-dimensional cams, bellows, and servo valves to schedule fuel flow based on inputs like compressor discharge pressure (Pcd), rotational speed (Ng), and ambient temperature.
Full Authority Control: Manages the entire operating envelope of the APU, including:
Start & Acceleration Fuel Scheduling: Provides a precisely controlled fuel schedule to ensure a rapid, cool start and a smooth acceleration to governed speed.
Isochronous Speed Governing: Maintains a constant APU RPM under all electrical and pneumatic load conditions, which is essential for stable AC power generation.
Surge & Overtemperature Protection: Automatically modulates fuel flow to keep the engine within its safe operating limits, preventing compressor surge and exhaust gas temperature (EGT) exceedances.
High-Precision Components: The assembly is built with components machined to microscopic tolerances, including servo valves, metering orifices, and flyweight governors, all operating within a sealed, fuel-filled housing.
Genuine OEM Component: As a genuine Honeywell factory unit, it guarantees the correct fuel schedules, calibration, and interface with the APU's electronic controller and other systems, ensuring full airworthiness.
Technical Specifications
Part Number: 3883240-7
Component Type: Hydromechanical Fuel Control Unit (FCU)
OEM Manufacturer: Honeywell Aerospace
Primary Function: Meters and schedules fuel flow for APU operation.
Control Type: Hydromechanical with electronic supervision.
Fluid Compatibility: Jet A, Jet A-1, and approved turbine engine fuels.
Certification: FAA / EASA Production Approval
Aircraft Compatibility
The 3883240-7 is the specified fuel control unit for some of the most common APUs installed in the world's premier long-range and large-cabin business jets.
Primary APU Models:
Honeywell GTCP36-100 & GTCP36-150 Series
Common Aircraft Platforms:
Bombardier: Challenger 601, 604; Global Express
Dassault Falcon: 50, 900, 2000
Gulfstream: GIV, GV, G450, G550
Applications
The 3883240-7 is a flight-critical component at the heart of the APU system:
APU Operation: The sole component responsible for managing the APU's fuel supply, making it essential for starting the APU and running it under load.
Engine Overhaul & Repair: A primary component that is removed, tested, calibrated, and certified at a specialized overhaul facility during any major APU service.
Troubleshooting APU Faults: A key component to investigate when diagnosing APU issues such as hung starts, failure to start, over-speed, or over-temperature events.
Why Choose 3883240-7?
The Auxiliary Power Unit is a high-value, complex turbine engine essential for the operational flexibility of a modern business jet. The Fuel Control Unit is the most complex and critical component of that APU. Using a genuine Honeywell 3883240-7 is the only way to ensure the unit has the correct, certified fuel schedules and safety logic for your specific APU model. There is no substitute for the proven reliability and safety of a genuine, fully traceable OEM part.
The Honeywell 3883240-7 FCU is a masterpiece of analog computing. The core of its logic is a three-dimensional cam that is both rotated by the pilot's power lever input and moved axially by an aneroid bellows sensing compressor inlet temperature and pressure. A follower rides on the complex, contoured surface of this cam. The position of the follower directly controls a metering valve, which sets the primary fuel flow. Additional inputs from a flyweight governor (sensing RPM) and temperature sensors trim this primary fuel schedule via a series of servo valves and orifices. This purely mechanical system is incredibly reliable and is not dependent on the aircraft's primary electrical power to safely manage the engine's operation, a key safety feature for an engine component.
Note: This is a flight-critical, serialized, and life-limited engine component. Installation, rigging, and testing must be performed by a certified AME or A&P mechanic at a qualified Part 145 repair station with the appropriate ratings and test equipment, in strict accordance with the current Honeywell APU maintenance manual. All work must be properly documented in the aircraft's and engine's permanent records.
