L-1011 Procedure: Preflight Check - Fuel System, Fuel Control Amplifier, Fuel Used and Engine Oil Panel

From Lockheed L-1011 Flight Training Manual

Fuel Panel

• Verify refueling is complete and the REFUEL POWER ON switch legend is extinguished. 
• Test the fuel quantity system. Check that fuel quantity indicators and digital readouts drive towards FULL. The 2L and 2R INBD LOW quantity lights illuminate, and FUEL SYSTEM annunciator light on the CAWP is illuminated. 
• Latch in one pump switch on 2L or 2R thank, and open all three cross feed valve. This provides full pressure to all engines in preparation for start. 
• All amber lights should be extinguished, and all tank valve and cross feed valve switchlight flow bars illuminated, as well as one tank pump switch flow bar in 2L or 2R tank. 

Fuel Dump Panel 

• All light are extinguished.

Fuel Control Amplifier

• Switches should be unlatched and guarded and OVRD legend extinguished. 

Engine Fuel Used Panel

• Turn the test knob on each indicator and observe the fuel flow indicators drive to 10,000 pph, and the Fuel Used indicators increase at that rate. Fuel Used indicators are then reset by the Fuel Used Reset switch on the Fuel System panel. 

Engine Oil Panel

• Check all FILER PRESSURE lights extinguished. 
• Test the pressure gauges with the PRESS IND test switch. Oil pressure indicators go to the 9 o'clock position. 
• The (3) three oil temperature gauges should indicate approximately the same, depending on time since engine shutdown. 
• Oil quantity should be adequate for the flight (normally 15 - 20 US quarts)

L-1011 Trainer Installation: Fuel Indication - Power-On Tests

L-1011 Trainer - Fuel Indication System

Getting the instrumentation online is quite exciting because suddenly the Lockheed L-1011 simulator/trainer gradually starts to come alive. Today I powered up the Fuel Indication system. It consists of 4 tank gauges and a fuel totalizer. The four fuel gauges feed signals to the Fuel Totalizer who then displays the total fuel load and allows for the Gross Weight of the aircraft to be entered prior to takeoff.

I have previously quite extensively blogged about the Fuel Level indicators, and you can find the more detailed blog posting on the Fuel Level indicator and the Fuel Totalizer by clicking on the link.

Below is a video that shows the #2L and the #1 fuel level gauges active and feeding data into the totalizer on the left hand side. For the test the indicators are instructed do point to roughly 1/2 tank full by supplying 5VDC to the instruments.

We are missing a Deutsch 15-S7 connector ... until then we are not able to power up the #3 tank gauge. If you have one ... let me know.

L-1011 Trainer Installation: Fuel Used Instrument Power-Up - 400Hz Power System

Here is a video of the first set of instruments powered from the 400Hz distribution system in the Lockheed L-1011 simulator at the National Museum of Commercial Aviation. You can find a lot more detail on the Fuel Used instruments as part of the Fuel Consumed Indicator blog posting. Providing these first three instruments with the 115V 400Hz power from the AC Bus 1 Ext, AC Bus 2 Ext and AC Bus 3 Ext subsystems checks the 400Hz system end to end:

Below is a more detailed description of the Fuel Flow system on the L-1011. 

L-1011 Engine Fuel Used System - From Delta Pilot's Reference

L-1011 Trainer Installation: Indicator Lighting Buildout

L-1011 Trainer Buildout: Indicator Lighting

Making small incremental steps with the buildout of the Indicator Lighting systems. The indicators (switchlights and annunciators) use circuitry and power sources independent from the cockpit instrument lights or the panel light plates. As we work through the indicator lighting build out we are also re-tooling the indicator lights from 28VDC incandescent lights to 24VDC LEDs. It's amazing how much that cuts down on heat produced in the sim, especially considering the fact that the L-1011 cockpit has hundreds of lights.

Once the progressive power-up of the indicator lights has completed we will start switching to connecting the switchlight and annunciators to the Digital I/O subsystems.

L-1011 Trainer Buildout: Fuel System Indicator Lights

L-1011 Trainer Installation: Fuel System Panel

L-1011 Trainer: Fuel System Panel

In this posting I conducted some tests with the Lockheed L–1011 fuel system panel. 

The image above shows the Lockheed L–1011 Fuel System panel illuminated in switch light test mode. Many of the system panels have a test input that allows for quick illumination of all of the switchlights and annunciators on a single panel. 

The image below shows a typical panel configuration when sitting at a parking position with let's say only the engine 2 running. 

L-1011 Trainer: Fuel System Panel

Below is the pressurized fuel flow path from Tank 2R to Engine 2 marked with the dashed orange line:

L-1011 Trainer: Fuel System - Tank 2R Fuel Pressure to Engine 2

Also, as I am bringing these panels online I am switching them from incandescent to LEDs. The LEDs help return the yellowed switch light lenses back to white.

L-1011 Trainer: Fuel System Panel LED Replacement

In the image above the Tank 1 Pump number 2 has been converted to LED lighting.

L-1011 Engine: Engine Fuel System

Low Pressure Pump

Receives fuel from aircraft system and ensures satisfactory pressure to the high pressure pump. Has a scroll type impeller working on an induction and centrifugal principle.

L.P. Fuel cooled Oil Cooler 

Engine oil system uses low pressure fuel as an oil cooling medium Conversely maintains fuel temperature above 0ºC for fuel heating.

High Pressure Pump

Delivers the required fuel flow to the combustion chamber as scheduled by the fuel regulator. A gear type pump.

Fuel Regulator 

Controls the high pressure pump output according to signals received from the pressure ratio control and HP shaft speed. A mechanical unit driven but he external gearbox.

Pressure Ratio Control 

Tells the fuel regulator the fuel flow required to achieve the P4/P1 pressure ratio selected by the pilot's throttle lever. It is part of the fuel regulator.

Control Signal Amplifier

This unit signals the high pressure fuel pump when N1 & N2 or TGT reach predetermined maximums. The HP fuel pump then controls fuel flow to prevent here maximums from being exceeded.

Starting Fuel Regulator 

Ensures a suitable fuel flow for light up and acceleration under all conditions.

Manual Enrichment Solenoid 

Provides extra fuel during the start cycle. Selected by the pilot through the Start/Fuel/Ignition switch.

H.P. Shutoff Valve 

Controls the fuel flow to the fuel spray nozzles when starting and stopping the engine. Electrically actuated valve.

Fuel Flowmeter

Provides signal of engine fuel flow and fuel used to the flight deck instruments. 

Avionics Bending: Total Fuel Quantity Indicator - Pinout

The Total Fuel Quantity Indicator is used to display the aggregate data from all individual Tank Fuel gauges. The instrument has two digital drum displays showing the total gross weight and the total fuel weight. The gross weight can be manually adjusted to give the total weight.

Just as the the individual Tank Fuel indicators, the Total Fuel Quantity Indicator is made by Simmonds Precision in Vergennes, Vermont. The one used on the L-1011 has a manufacturer serial number of 393081-105.

The Total Fuel Quantity Indicator consists of a several components:

1. DC comparator for each input channel

2. Polarity detector to determine if the instruments counts up or down

3. The stepper motor Controller

Each of the Tank Fuel Gauges has a DC voltage output on Pin 7. The DC voltage corresponds to the tank fluid level. The total fuel quantity indicator takes the four tank input signals and combines them into a single value. Below is the Pin-out for the Simmonds Precision 393081 Total Fuel Quantity Indicator:

Pin 1: Instrument Lighting 5VAC (Hi)

Pin 2: Instrument Lighting 5VAC (Lo)

Pin 3: Not Used

Pin 4: Not Used

Pin 5: Not Used

Pin 6: GND

Pin 7: 115VAC 400Hz Power Input

Pin 8: Not Used

Pin 9: Not Used

Pin 10: Tank Signal Ground

Pin 11: GND

Pin 12: Tank No 1 Input

Pin 13: Tank No. 2R Input

Pin 14: Tank No. 3 Input

Pin 14: Not Used

Pin 15: Tank No. 2L Input

Avionics Bending: Fuel Quantity Indicator - Pinout

There are four Fuel Quantity Indicators and one Fuel Totalizer on the L-1011 Fuel System panel. The four Fuel Quantity indicators have identical pinouts, however they have different scales. The Fuel Totalizer pinout will be discussed in another blog posting.

The instrument is a combination of pointer and digital display as seen below. The one I use in the example here shows the scale in Kilogram [kg] as would have been used on, let's say, a British Airways L-1011.

The instrument was made by Simmonds Precision in Vergennes, Vermont. The particular one used here in the blog posting has a MFR Part Number of 393090-115 and a Serial Number of 129E.

The arm and the digital display in the instrument are driven by a stepper motor. The tank level would have been sent to the indicator from a Tank Signal Conditioning unit located close to the actual tank. The main component pieces of the instrument are:

1. A DC Comparator analyzing the Tank Quantity as a DC value above GND.

2. A Polarity Detector to see if the counter should count UP or DOWN.

3. The Stepper Motor logic.

So all in all a rather simple instrument. Here is the pin-out for a Simmonds Precision Primary Fuel Quantity Indicator Model 393090:

Pin 1: Instrument Lighting 5VAC (Hi) or 5VDC

Pin 2: Instrument Lighting 5VAC (Lo) or GND

Pin 3: Not Used

Pin 4: Not Used

Pin 5: Tank Quantity GROUND

Pin 6: Tank Quantity as DC Voltage - Input

Pin 7: Tank Quantity as DC Voltage to Fuel Totalizer - Output

Pin 8: Not Used

Pin 9: Not Used

Pin 10: Not Used

Pin 11: Not Used

Pin 12: 115V 400Hz Power (Hi)

Pin 13: Power Ground

Pin 14: Not Used

L-1011 General Aircraft Characteristics: -500 Fuel Tank Arrangement (25-9)

The L-1011-500 has six fuel storage tanks. The are identified as Tank 1, Tank 1A, Tank 2L, Tank 2R, Tank3 and Tank 3A.

Thanks 1A and 3A are center section fuel tanks which have been added to allow the -500 increased fuel capacity and range.

System Description by Don Pierce: Fuel System

"Don Pierce is a L-1011 Flight Test Engineer (Ship 3), then in Customer Training, then he had his own business doing maintenance training for L-1011 customers. Don is nothing but amazing in his knowledge of the L-1011. I am going to post several conversations on systems that I have had with Don over the past few weeks"

The FUEL SYSTEM panel you show in the photo does not have the switchlights for Tanks 1A and 3A. The panel could be used for a -200 that does not have center section fuel. Although it is assumed that all -100s and all -200s have center section fuel, that is not a requirement to have that designation. The designation reflects takeoff weight (430,000 vs,466,000) and type of engine (-22B vs. -524) . The 466,000 T..O. weight has been increased to 472,000 lb. on some "non -500" L-1011s.

The Tank 2L and 2R indicators, not installed in the photo, normally indicate the total quantity in the respective tank (2L or 2R). The tanks are divided into two sections - inboard and outboard. To see how much fuel is in the inboard¨section only, latch in the 2L INBD or 2R INBD switchlight; the QTY legend will illuminate to indicate the switchlight is latched in. Now the indicator will display the quantify of fuel that is in the inboard section only. The LOW light will illuminate regardless of switchlight position. It illuminates when the fuel quantity in the tank's surge box is down to 700# (about 320 kg - if the airline has metric gages).

Each tank has two boost pumps - which are activated when the respective switchlights are latched in. The flowbar in the switchlight illuminates to show switchlight position; it does not indicate whether or not the pump is operating. The LOW light in the switchlight will illuminate if the switchlight is latched in and boost pump output pressure is less than about 6 psi. This means that the LOW light will not illuminate if the switchlight is unlatched.

The gage in the center of the panel is a "totalizer" and show the sum amount of fuel available. The FE would used the SET knob in the instrument to dial in the starting weight of the plane, so he then has an instant readout of weight of the plane and total remaining fuel as the fuel burns off. NOTE: The reading would change when a QTY/LOW switchlight is latched in.

Pressing and holding the QUANTITY TEST switch below the GROSS WT/TOTAL FUEL indicator ("totalizer") will cause the tank gage readings to travel to the full mark, the GROSS WT/TOTAL FUEL indicator readings to increase, and the LOW lights in the QTY/LOW switchlights to illuminate.

There are three crossfeed valves and dual-legend switchlights. The flowbar illuminates when the switchlight is latched in (switchlight position). The other part is blue and is a "disagreement" light. It indicates a "disagreement" between the present position of the valve and the commanded position. So when a switchlight is first latched in, the blue light will illuminate until the valve is open, then the light extinguishes. So a flowbar and no blue light means the valve is selected open and is open. That's the way it should be, for crossfeed conditions. The crossfeed valves would be closed if it is desired to feed directly tank-to-engine. The crossfeed valves allows the FE to feed any engine from any tank, with only two crossfeed valves being operable.

This explanation about valve position and indication also applies to the three guarded TANK VALVE switchlights. For engines 1 and 3, the Tank Valve flowbars are also controlled by the FIRE PULL Handles.

The amber EMERGENCY SHUTOFF lights (one each for engine 1 and 3, and two for engine 2 and the APU) illuminate only when the emergency firewall shutoff valve position and the selected position of the valve (selected only by a FIRE PULL handle) is in disagreement - similar to the blue lights.

The REFUEL POWER "ON" light illuminates whenever the Fueling Power toggle switch at the Fueling panel is at the "On" position. Momentarily pressing this switchlight will remove power from the Fueling Panel, because the external Fueling Power toggle switch is operated through a holding relay. NOTE: The 2L/2R INBD-only feature is inhibited when the Fueling Power toggle switch is "on".

The FUEL USE RESET momentary switchlight is used to rest the fuel used indicators (not shown) in the panel to the right of the FUEL SYSTEM panel.

My "chat" here relates to the indicators and switchlights on the panel. Fuel system operation is yet another thing. This is true is just about every topic I've discussed so far - I've covered panel operation only - not system operation. That leads into many more hours of chat - nearly a full course.

Don

Avionics Bending: Fuel System Panel (Prototype)

Today, I developed the prototype for a 8pin switch connector that I will use all throughout the Lockheed L-1011 project. Please forgive the rough appearance of the Fuel System panel, but I have not re-worked the paint on the light plate (we will do that at a later time in the project).

The image below shows the non-I2C version of the prototype. Here, the ATmega32U4 process drives a Darlington array directly. The IC to the left is a 10K Resistor array that I use as pull-ups for the switch inputs.


The image below shows the computer controlling two of the Fuel Panel switched. The right hand side switch for the "TANK 3 PUMPS" has a LOW indicator field illuminated (LED1 + LED3) and the left switch for the "TANK 2R PUMPS" has a FLOW BAR illuminated (LED2 + LED4). All switches have been re-tooled to use the LED's that we started building for the project.


I will post the schematic and the board layout in detail once I get ready to have the generic 16-Switch I/O Boards made.

Avionics Bending - Prep Part 2: Fuel System Panel

Still on the Fuel System panel for the Lockheed L-1011 project. In this posting, we will attach an 8pin wire-to-board connector to each switch. There are three different types of switches:

1. Switches with two horizontal fields
2. Switches with two vertical fields
3. Switches with one single field

The Fuel System panel features all 3 of the above.



Here is the pin-out for a switch with two horizontal fields:

Connector Pin 1 ---> Switch Cable 1 (LED 1) Top Field Left
Connector Pin 2 ---> Switch Cable 2 (LED 2) Top Field Right
Connector Pin 3 ---> Switch Cable 3 (LED 3) Bottom Field Left
Connector Pin 4 ---> Switch Cable 4 (LED 4) Bottom Field Right
Connector Pin 5 ---> Switch Cable C (Command Anode)
Connector Pin 6 ---> Switch Cable 10 (Switch Unlatched)
Connector Pin 7 ---> Switch Cable 11 (Switch Latched)
Connector Pin 8 ---> Switch Cable 9 (GND)

Now that all the cables have a connector and the cables are tied together, the madness from the last posting is gone. This is a step that every of the L-1011 panels will go through.

Avionics Bending - Prep Part 1: Fuel System Panel

In this posting i start the preparation work for the Fuel System Panel of the Lockheed L-1011 project. The first step is to break down the original cabling, remove the pin boards that Lockheed used for the switch connections and attach a 8 pin wire-to-board connector to each switch.

The next two images show the original cabling for the L-1011 Fuel System panel.

1. Back View.


2. Bottom View


In the next image I pointed to the pin boards. Each switch is soldered to a ping with a number of different connections. The pin boards are not really useful for my project, so remove them.


In order to preserve as much of the original hookup wire, I cut the cables right at the point where they had been soldered to a pin on the small boards.


Once all cables have been cut, I roll them up and tie them together for each switch. Looks pretty mad, but in the next preparation step we will clean that up and attach the 8pin wire-to-board connectors.

Original Flight Hardware: Fuel System

The fuel control on the Lockheed L-1011 take a prominent spot on the lower section of the flight engineer panel. There are several tank configurations for the -1, -200 and -500 models of the L-1011. The configuration that I have a tank panel for is shown below.


Here is a general description of the L-1011 fuel system as described in a 1977 Eastern Airlines flight manual:

The fuel system consists of four wing tanks which operate as a three-tank system. The inboard tanks (No. 1 and No. 3) supply ENG1 and ENG3. The outboard tanks (No. 2L and No. 2R) are manifolded together through a flow equalizer to supply ENG2 with fuel. Tanks 2L and 2R are divided into inboard compartment and outboard compartments. The compartments are connected by a fuel line equipped with a float valve. Fuel is used first from the inboard compartment until 1000 pounds remain. Fuel from the outboard compartment then transfers through the float valve to maintain the 1000 pound level in the inboard compartment until the outboard compartment is depleted.

The No. 2 engine fuel lines supply the APU. When the ENG2 tank valve is closed, the APU can be supplied from tank No. 3.

The picture below shows the panel as I have it today (12/31/2009). There are 3 tank gauges missing (the one on the left hand side is actually a tank gauge from the external fuel control panel of the L-1011).


Each tank has two fuel pumps and fuel flow can be controlled with cross-feed valves (see below). An in-transit light for each fuel valve is illuminated, while the valve motor is engergized, during valve operating or closing.

Tanks 2L and 2R normally act as one tank. Fuel from tanks 2L and 2R feeds through the flow equalizer even during crossfeeding.


The fuel temperature in each tank can be displayed with the FUEL TEMPERATURE INDICATOR and the FUEL TEMPERATURE TEST SWITCH located on the lower left of the Fuel System panel.






Panel Location