AVStar Fuel Systems — Frequently Asked Questions
AVStar manufactures aircraft fuel system components under FAA Parts Manufacturer Approval (PMA) in accordance with 14 CFR Part 21 (FAA-PMA No. PQ4021CE), supporting production, inspection, and traceability of approved replacement parts for certificated aircraft.
AVStar also operates an FAA-certified Repair Station under 14 CFR Part 145 (Certificate No. V1RR580Y), providing overhaul, inspection, and return-to-service of fuel system components in accordance with approved capabilities.
In addition, AVStar holds EASA Part 145 approval (EASA.145.6579), supporting maintenance and return-to-service in accordance with European Aviation Safety Agency requirements.
From a quality management standpoint, AVStar operates under AS9100 quality system standards:
- The Auburn, New York facility is AS9100 registered
- The Jupiter, Florida facility operates in compliance with AS9100 practices
These combined approvals and quality systems support consistent manufacturing, maintenance, inspection, and documentation of AVStar fuel system components used in general aviation aircraft.
The Lambda Flow Bench is AVStar’s in-house testing and verification system used to evaluate fuel system performance prior to shipment.
The system is designed to replicate controlled airflow and fuel flow conditions representative of engine operation, allowing technicians to:
• verify fuel metering accuracy and consistency
• measure fuel flow rates and system pressures
• identify irregularities prior to release
The Lambda Flow Bench also incorporates integrated visual monitoring, allowing technicians to observe fuel atomization characteristics within the carburetor or fuel system. This provides an additional method for identifying potential issues such as improper spray patterns or leakage.
Each fuel system undergoes a final functional test using this equipment as part of AVStar’s inspection and quality control process.
This approach supports consistent calibration, helps identify issues before installation, and contributes to overall fuel system reliability in service.
AVStar fuel system components are CNC-machined from 6061-T6 aluminum billet rather than produced as castings.
Billet machining offers several manufacturing advantages, including:
- consistent material structure
- reduced likelihood of internal porosity
- improved dimensional control during machining
6061-T6 aluminum also has higher material yield strength than many aluminum alloys historically used in cast fuel system housings.
Certain legacy carburetor designs have experienced body-to-bowl fuel leakage associated with gasket compression or relaxation over time.
AVStar uses updated gasket materials designed to improve long-term sealing stability between carburetor components.
In addition, AVStar carburetor housings are CNC-machined from 6061-T6 aluminum billet, which provides consistent material structure and improved thread integrity compared to many legacy cast housings. This allows for the use of higher, controlled torque values during assembly, increasing clamping force across the gasket interface.
The combination of improved gasket materials and stable clamping conditions is intended to address conditions discussed in service bulletins related to carburetor fuel leakage.
AVStar fuel system components are CNC-machined from 6061-T6 aluminum billet rather than produced as castings.
AVStar’s carburetors average approximately a 15% reduction in weight by design compared to legacy cast carburetors.
Aluminum components used in AVStar fuel systems are anodized to improve corrosion resistance and surface durability.
AVStar has been manufacturing fuel system components for general aviation piston engines for more than two decades, supporting aircraft owners, engine shops, and distributors worldwide.
Products and Compatibility
AVStar designs, manufactures, and distributes fuel system components for air-cooled piston aircraft engines, including:
- aircraft carburetors
- fuel injection servos
- flow dividers (fuel manifold valves)
- fuel injector nozzles
- related fuel system components
These products support a wide range of general aviation aircraft.
Are AVStar fuel systems FAA approved?
Many AVStar components are produced under FAA Parts Manufacturer Approval (PMA).
FAA-PMA approval confirms that a replacement part has been reviewed and approved by the FAA as meeting applicable airworthiness requirements for installation on certificated aircraft.
AVStar is a manufacturer of aircraft fuel system components.
Fuel system products are designed, manufactured, assembled, and tested at AVStar facilities, between the company’s operations in Auburn, New York and Jupiter, Florida.
Many AVStar fuel system components are designed for Lycoming engine applications and are used as replacement parts on a wide range of Lycoming-powered aircraft.
Always verify engine and aircraft compatibility before installation.
Outright Purchase
An outright purchase means a new or overhauled unit is purchased with no core return required.
On AVStar part numbers, an “-F” designation indicates an outright unit.
Exchange Purchase
An exchange purchase allows the customer to buy a replacement unit at a reduced price and return their existing component as a core after installation.
On AVStar part numbers, an “-E” designation indicates an exchange unit, where a core return is required.
Exchange programs help reduce aircraft downtime during maintenance.
Operation and Maintenance Questions
Fuel leaks in aircraft carburetors can occur for several reasons, most commonly related to seal degradation, gasket compression over time, or mechanical wear in the carburetor assembly.
Common causes include:
- relaxation or deterioration of bowl gaskets
- improper torque or loosening of fasteners
- corrosion or thread wear around drain plugs or fittings
- damage to sealing surfaces during maintenance
- aging elastomer components exposed to fuel and heat cycles
Service bulletins issued by engine and carburetor manufacturers have historically addressed certain leak conditions related to body-to-bowl gasket compression in legacy carburetor designs.
If a fuel leak is suspected, the carburetor should be inspected by a qualified A&P mechanic or accessory overhaul facility.
Continuous-flow fuel injection systems meter fuel to each cylinder based on airflow through the engine induction system.
The system typically includes three primary components:
- fuel injection servo – meters fuel based on airflow entering the engine
- flow divider (fuel manifold valve) – distributes fuel evenly to each cylinder
- fuel injector nozzles – deliver atomized fuel into each intake port
As intake air passes through the fuel injection servo, the system meters fuel proportionally to maintain the appropriate air-fuel ratio. The metered fuel is routed to the flow divider, which distributes fuel through individual lines to each injector nozzle.
Unlike carburetors, continuous-flow systems inject fuel at each cylinder intake port rather than mixing fuel and air in a central carburetor body.
These systems are widely used on many Lycoming and Continental fuel-injected piston engines.
Overhaul intervals for fuel system components should follow:
- the engine manufacturer’s recommendations
- the component manufacturer’s service instructions or bulletins
- applicable airworthiness directives
For AVStar carburetors, Service Bulletin AFS-SB7 provides guidance on inspection and overhaul intervals. This bulletin outlines continued airworthiness requirements specific to AVStar carburetor designs and should be followed in conjunction with engine manufacturer guidance.
For fuel injection servos, overhaul intervals typically align with the engine’s recommended time between overhaul (TBO). When operating on Lycoming engines, compliance with Lycoming Service Instruction 1009 establishes the applicable TBO schedule. Under these conditions, the fuel injection servo follows the same overhaul interval as the engine.
Earlier inspection or overhaul may be required due to, but not limited to, the following conditions:
- fuel leakage is observed
- fuel flow becomes inconsistent
- engine roughness or mixture control issues occur
- contamination or corrosion is identified during inspection
Because fuel metering components directly affect engine performance and safe operation, any suspected malfunction should be evaluated by a qualified maintenance technician or accessory repair facility.
Yes.
AVStar provides access to:
- technical publications
- service bulletins
- engine eligibility information
- customer technical support
Phone support is available during normal business hours.
AVStar Fuel Systems operates facilities in Jupiter, Florida and Auburn, New York.
Technical support and sales assistance are available by phone during normal business hours.