While the various fuel pumps and valves on the -400 are mainly controlled by the automation during the flight, some manual crew actions are necessary as well.
Both, the automatic and the manual actions can exactly be demonstrated in Precision Simulator PS1. As desired, the fuel flow simulation speed can either be the same as in real life, or accelerated for training and demo purposes.
100% “free play” capability is provided in the simulation: All fuel controls and instruments are fully functioning and interact with the other aircraft systems (electrical, FMC etc.) in real time, incorporating the same logic and criteria of the real 744 systems. The pictures below show how the simulation looks like on a PC monitor.


Which components are modeled in PS1 to achieve this authentic Fuel System simulation?
 

• The pumps:
   - All Override, APU and Main Tank pumps.
   - Hydromechanical Jet Pump, Electrical Scavenge Pump
   - Engine integrated pumps (suction feed).
   - Auto-control by air/ground logic, flap position, tank quantities.
   - Powered by individual AC & DC busses of Electrical simulation.
   - Functioning switches and “Low Pressure” lights on Fuel Panel.
   - Pump status affects fuel distribution model accordingly.
   - On/off/standby/fail symbology on EICAS Fuel Synoptic.

• The four Cross Feed Valves:
   - Auto-control of valve 2+3 by flap position.
   - Powered by Main Battery Bus of Electrical simulation.
   - Functioning switches and “Valve” lights on overhead panel.
   - Valve positions influence fuel distribution model accordingly.
   - Active close/open/fail symbology on EICAS Fuel Synoptic.

• Jettison System:
   - Powered by various AC & DC busses of Electrical simulation.
   - Includes all Jettison Pumps in the various tanks.
   - The two Jettison Nozzle Valves.
   - Functioning Nozzle Valve switches and lights on Fuel Panel.
   - Fuel To Remain Selector on overhead panel.
   - Auto-control by Fuel To Remain and imbalance protection.
   - Pump status affects fuel distribution model accordingly.
   - Active on/off/fail symbology on EICAS Fuel Synoptic.
   - Jettison Time indication on EICAS.

• The Main Tank Transfer Valves (gravity transfer):
   - Active transfer “arrow” symbols on EICAS Fuel Synoptic.
   - Functioning manual control on overhead Panel.
   - Auto-control based upon main tank quantities or jettison.
   - Powered by respective DC Busses of Electrical simulation.
   - Valve positions influence fuel distribution model accordingly.

• The Reserve Tank Transfer Valves (gravity transfer):
   - Active transfer “arrow” symbols on EICAS Fuel Synoptic.
   - Auto-control based upon main tank 2 + 3 quantity.
   - Powered by respective DC Busses of Electrical simulation.
   - Valve positions influence fuel distribution model accordingly.

• Fuel System Management Cards (FSMCs):
   - Powered by respective DC Busses of Electrical simulation.
   - Auto-control of pumps and valves during flight progress.
   - Depends on tank quantities, balance, flap position etc.
   - Manual “Tank-To-Engine” reconfiguration required.

• Fuel Quantity Indication Systems:
   - Powered by respective DC Busses of Electrical simulation.
   - “Totalizer” (based upon fuel quantity sensors in tanks).
   - “Calculated” (based upon fuel flow measurement).
   - Disagreement can be simulated.
   - Individual tank quantity indications on EICAS.
   - Yellow quantity displays in case of low quantity or imbalance.
   - Fuel Ballast Alert for 744 Combis.

• Fuel Temperature Simulation:
   - Depends on OAT (Instructor’s Page/Weather) and airspeed.
   - Delayed response when TAT is changing.
   - EICAS Low Fuel Temp alert.
   - Different types of fuel available.
   - Fuel flow stagnation when below freezing point.

• Connection to FMC:
   - Totalizer and Calculated Fuel Remain on “PROGR 2/2” page.
   - Fuel Remain predictions on VNAV and RTE DATA pages.

• Airline options selectable:
   - Type of scavenge pump in Center Wing Tank.
   - APU fuel supply asymetrical or symetrical from tank 2 + 3.
   - Stabilizer tank.
   - “MLW” feature for Jettison Fuel To Remain selector.
   - Quantity indications in LBS or KGS.


Which “Abnormals” can be simulated in PS1?
 

• FSMC failure (Fuel Management Cards A and/or B inop.).
• All sorts of Fuel Tank imbalance.
• Fuel Jettison System A and/or B failure.
• Individual pump failures.
• Individual valve failures.
• Low Fuel Pressure.
• Low Fuel Temperature.
• Low Fuel Quantity.
• Fuel Leak in any engine (“Totalizer” / “Calculated” disagree).


Limitations in version 1.3: Switches on the “Maintenance Panel” are not available. The simulation is based upon a normally configured maintenance panel.

Examples -  Fuel System Simulation

Photographs of PS1 running on a 19” PC monitor

LEFT: PS1 provides a highly realistic simulation of the Fuel System. Downright every imaginable normal and abnormal configuration can be simulated.
In this picture an engine failure occured after take-off. The Fuel Jettison system has been started while flying a hold over Tokyo’s Pacific coast.

RIGHT: Both Jettison Nozzle Valves has been turned on with Jettison Controller A managing the fuel dumping process.
All switches and indications displayed on the PC monitor are fully functioning (or “mal”-functioning for training scenarios if desired). Like on the real 744, each function is a part of an internal, highly complex network of devices and interfaces.

In order to learn how the systems interact with each other, the Fuel Panel and the EICAS Fuel Synoptic can be viewed on the PC monitor at the same time.

BELOW: The lower right-hand corner shows the secondary EICAS screen with the Fuel Synoptic selected. Total fuel quantity is currently 166.2 tonnes, selected fuel to remain is 75 tonnes, and time until jettison is complete is 46 minutes.

LEFT: The stabilizer tank is now empty. The PRESS lights in the Stab Pump switches illuminate, the EICAS stab pump symbols turn yellow, and the respective EICAS Advisory Messages inform the crew. Total fuel quantity is now 122.3 tonnes. The time remaining until the total quantity is decreased to 75 tonnes is 31 minutes.

RIGHT: The target gross weight in this scenario is the maximum landing weight (MLW) of approx. 285 tonnes, plus some fuel weight required to return to the airport. The FMC APPROACH REF page indicates that the current gross weight is 290.3 tonnes.

LEFT: The total fuel quantity is now below 75 tonnes. The EICAS Fuel To Remain indicator turns white and starts flashing while Jettison Controller “A” is automatically stopping the fuel dumping process.

RIGHT: Although the Jettison process has been terminated automatically, the left and right Nozzle valve switches and the Jettison Controller selector has been turned off manually. The jettison flow bars on the lower EICAS screen are now removed.

BELOW: This picture is another demonstration of PS1’s real time “free play” capability and flexibility. In this rather “chaotic” scenario the fuel temperature is dropping below -37°C (a higher Mach number should now be selected, or a different altitude) while an imbalance between main tank 1 and 4 occured. Also, the Left Stab Tank Pump Switch has been turned on, although the tank is empty (resulting in a yellow low pressure alert accordingly).

LEFT: In the “Preflight Items” menu on the sim’s integrated Instructor’s Page the user can select the desired fuel quantity as well as a certain type of fuel.

RIGHT: In this scenario a fuel leak occured in one of the four engines. The Fuel Panel must be reconfigured to find out which engine is affected. After a certain period of time, when the problem is analyzed on the EICAS synoptic, the affected engine must be shut down. From now on, the “Totalizer” fuel indication should be used by selecting the “<USE” prompt on the FMC (using the PC mouse or keyboard).

What do other aviation professionals say about this simulator?

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