Introduction to Fuel Management in Prepar3D

Accurate fuel system simulation is a cornerstone of immersive flight simulation. In Prepar3D (P3D), the fuel management subsystem handles everything from tank loading and pump operation to crossfeed logic and fuel flow to the engines. Aerosimulations provides an advanced, add-on fuel management system that elevates this experience from a simple gauge display to a fully functional replica of real-world aircraft fuel operations. Whether you are practicing commercial airliner procedures or flying complex general aviation aircraft, integrating the Aerosimulations system allows you to train realistic fuel transfers, manage center of gravity, and handle emergency fuel scenarios. This article provides a comprehensive guide to configuring and optimizing the Aerosimulations fuel management system within your P3D aircraft.

Understanding the Aerosimulations Fuel Management System

The Aerosimulations fuel management system is a modular framework that overlays P3D's default fuel logic with more detailed component modeling. It includes:

  • Fuel Tanks: Multiple tanks (main, auxiliary, center, wing tip) each with configurable capacity, location, and transfer restrictions.
  • Fuel Pumps: Boost pumps, transfer pumps, and engine-driven pumps simulated with electrical and pressure logic.
  • Crossfeed and Valves: Manual and automatic crossfeed valves, fuel shut-off valves, and gravity feed paths.
  • Fuel Gauges: Analog and digital gauges displaying total fuel, individual tank quantities, flow rates, and fuel temperature.
  • Control Interfaces: Virtual cockpit switches, knobs, and pop-up panels that interact with the simulation variables.

These components communicate through P3D's SimConnect API and custom XML logic. The system can be tailored to match specific aircraft types, from tubeliners to turboprops. Aerosimulations also provides failure simulation for pump failures, fuel leaks, and contamination, adding depth to training scenarios.

How the System Works with P3D's Default Fuel Model

P3D natively simulates fuel as a single mass property with simple flow to each engine. The Aerosimulations system intercepts these variables and enforces more realistic physics: fuel cannot transfer without pump power, crossfeed requires valve selection, and unusable fuel remains in the tanks. This is achieved through gauge scripts, panel logic, and modifications to the aircraft's XML configuration files. Understanding this interaction is key to proper configuration.

Prerequisites and Installation

Before configuring the fuel management system, ensure you have:

  • Prepar3D v4/v5/v6 (compatible versions)
  • Aerosimulations Fuel Management Package (latest version from their official site)
  • A target aircraft with accessible configuration files (e.g., PMDG, FSLabs, or default P3D aircraft) – note that integration may differ for each model.
  • Basic XML editing skills – the configuration uses standard XML schema; you can use Notepad++ or a similar text editor.

Install the Aerosimulations package by following the provided installer. Typically this copies gauge DLLs, XML templates, and sample configurations into your P3D root folder. After installation, a "Aerosimulations" folder appears under SimObjects/Airplanes/ with example aircraft. For your own aircraft, you will copy the relevant gauge entries and panel files.

Step-by-Step Configuration of Fuel Management in P3D Aircraft

1. Locate and Back Up Configuration Files

Open your target aircraft's folder under SimObjects/Airplanes/. The key files are:

  • aircraft.cfg – contains fuel tank definitions (tank groups, capacities, positions).
  • panel.cfg – references the fuel management gauge XML files.
  • panel/ folder – contains the visual gauge XML and any attached logic scripts.
  • Model/ folder – may include .mdl files with animation data.

Before making any changes, create a backup of these files. This allows you to revert if the configuration fails.

2. Adjust Fuel Tank Definitions in aircraft.cfg

Open aircraft.cfg and locate the [fuel] section. The Aerosimulations system expects a certain structure. For example:

[fuel]
LeftMain = 1000.0, -2.0, 0.0, 0.0, 0.0, 0.0, 1.0
RightMain = 1000.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0
Center = 500.0, 0.0, 0.0, 0.0, 0.0, 0.0, 2.0

Each line defines: Name = Capacity, StationX, StationY, StationZ, FuelType, UnusableAmount, TankGroup. Adjust capacities and positions to match the real aircraft. The TankGroup field (last number) determines which tanks can transfer between each other – groups must match for crossfeed to work. Consult the Aerosimulations documentation for proper group assignments.

3. Add Fuel Management Gauge References in panel.cfg

In the panel.cfg, add entries for the Aerosimulations fuel system gauges. Typically you will include:

  • FuelSystem.xml – the main logic gauge (invisible, runs in background).
  • FuelPanel.xml – a pop‑up control panel (optional).
  • Individual gauge references for standard P3D fuel gauges or custom ones.

Example gauge00 entry:

gauge00=Aerosimulations!FuelSystem, 0,0,0,0
gauge01=Aerosimulations!FuelPanel, 0,0,400,300

The first gauge (size 0,0) runs hidden, while the second provides a windowed interface. You may also map virtual cockpit buttons to Aerosimulations events using KeyEvent entries.

4. Integrate Aerosimulations Scripts for Advanced Logic

The Aerosimulations package includes XML scripts that override standard fuel flows. To enable them, add a [Fuel.0] or similar section in the aircraft.cfg if required. Some aircraft may need a custom FLT_SIM script or LUA file. Check the manual: many setups use a Systems.cfg or fuel_mod.xml inside the aircraft's panel/ folder. Copy the necessary scripts and modify variables like pump_on_, crossfeed_open_, etc.

For example, inside the FuelSystem.xml you can set parameters:

<Var name="CrossfeedEnable" valuator="bool" default="0"/>
<Var name="TransferRate" valuator="int" default="5"/>

5. Test the Configuration in P3D

Load the modified aircraft in P3D. Open the fuel panel (shift+1 or assigned keyboard shortcut). Observe the fuel quantity, pump status, and try transferring fuel between tanks. If nothing happens, verify that the gauge is loading without errors by checking My Documents/Prepar3D v5 Files/log.txt for SimConnect messages. Common errors include missing gauge files or syntax mistakes in the XML. Revert your changes if needed.

Advanced Configuration and Customization

Customizing Pump and Valve Behavior

You can adjust pump pressure, flow rates, and failure probabilities. Edit the FuelSystem.xml to set PumpFailureRate (e.g., 0.001 per hundred hours) and PumpOverheatTime. For crossfeed, you can restrict flow direction or require specific valve positions.

Simulating Fuel Management Failures

Aerosimulations supports realistic failures: fuel pump fail, tank leak, water contamination, or fuel imbalance. Enable these in the configuration file or via the failure manager gauge. This is invaluable for training emergency procedures such as crossfeed activation or fuel balancing.

Integrating with Third-Party Aircraft

Many high-fidelity payware aircraft (PMDG, FSLabs, A2A) have their own advanced fuel systems. Aerosimulations may conflict. In those cases, you can either disable the add-on fuel system of the aircraft or selectively replace only the gauge display. Alternatively, use Aerosimulations as a standalone fuel management trainer by assigning it to a simple default aircraft.

Troubleshooting Common Issues

  • Fuel not transferring: Check that pumps are powered (electric or engine-driven) and that crossfeed valves are open. Ensure tank groups are compatible.
  • Gauges show zero: The gauge may not be reading P3D variables correctly. Verify that the FuelSystem gauge is loaded (check log.txt). Also ensure the aircraft.cfg tank names match the gauge variable names.
  • Fuel leaks continuously: Check for incorrect tank group assignments causing infinite transfer. Also verify that the UnusableAmount is not set to a negative value.
  • P3D crashes on load: A syntax error in an XML file or gauge can cause a crash. Carefully validate the XML (use an online validator). Temporarily remove the Aerosimulations gauge to isolate the issue.
  • Incompatible with other add-ons: Some weather engines or system tools override fuel variables. Disable conflicting third-party programs one at a time.

For persistent problems, consult the Aerosimulations support forum or the Prepar3D Community Forum. Many users share their working configurations.

Best Practices for Realistic Fuel Management Operations

Pre-Flight Preparation

Always check fuel quantity and type before departure. Set the correct fuel load for your flight plan. Use the Aerosimulations panel to test pumps and valve operations during cold and dark start. Document the tank configuration in case of changes.

In-Flight Fuel Management

Monitor fuel flow and totalizer readings. Transfer fuel from auxiliary to main tanks as needed to maintain balance. For long-haul flights, schedule transfers to avoid excessive imbalance. Use the crossfeed feature to supply both engines from one side in the event of a pump failure. Update the fuel log every hour.

Post-Flight and Maintenance

Record any anomaly such as fuel imbalance or pump issues. Aerosimulations logs can be exported for debrief. Regular updates to the Aerosimulations package ensure compatibility with new P3D versions and fix bugs.

Conclusion

Integrating the Aerosimulations fuel management system into your P3D aircraft transforms fuel handling from a simplified model into a realistic, interactive subsystem. By carefully editing the aircraft’s configuration files, adding the correct gauges, and fine‑tuning parameters, you can replicate the procedures used by real pilots. Whether you are a hobbyist seeking deeper immersion or a trainee practicing fuel‑emergency drills, a properly configured Aerosimulations system delivers reliable, educational simulation. Start with the basic setup described here, then explore advanced features to customize your experience. For further reading, visit the Aerosimulations official website and the Prepar3D SimConnect SDK documentation. The realism you gain will make every flight more authentic and rewarding.