L-1011 Procedure: Preflight Check - Hydraulic and Electrical Panel

From Lockheed L-1011 Flight Training Manual

Hydraulic Panel 

• Hydraulic Fluid level - minimum 3/4 full. 
• The suction shutoff flow bars illuminated and the engine driven PUMP S/O flow bars illuminated. 
• The only amber lights that should be illuminated are the four engine driven PUMP OUTPUT LO PR lights. 
• Start B3 and C3 electric pumps and PTU's to charge the hydraulic pump accumulators. After that, place the pumps back to off. 

Electrical Panel

• If external power is available, it should be used. If not, use the APU
• IDG temp and power meter should reflect ambient or residual temperature and zero load. 
• With APU power, the only flow bars illuminated will be the APU generator field and generator breaker, and the three (3) bus tie breakers. 
• The only amber lights illuminated will be the three (3) engine driven IDG Disconnect LOW PRESS switches and the Open lights for each generator field and breaker. All other lights will be extinguished. 
• The Essential Power source selector should be in the NORM B3-(G1) position. 
• The Battery Switch is to ON 
• With the DC Meter selector, check all DC sources. Indications will be bus voltage and respective T/R amperage. All amperages should be equal. Battery should be pulse charging. Return selector to the essential transformer rectifier (ESS) position after checks. 
• Place the AC selector to the engine to be started. 

L-1011 Trainer Installation: AC an DC Standby Power from Battery

L-1011 Trainer: AC and DC STBY Power from Battery

Finished the L-1011 AC Standby (STBY) and DC STBY power fail-over to the on-board Battery yesterday evening. On the actual aircraft, once transferred to Battery power, the standby buses are alive for about 30 minutes before the Battery is depleted.

Normally, the DC STBY bus receives powered from the DC Essential bus and the AC STBY bus is powered by the AC Essential bus. The AC and DC STBY bus are the last resort to keep the aircraft operational in case of a complete loss of primary electrical systems. If the respective Essential power busses fail, the STBY busses are switched to the on-board Battery. AC power is created form the on-board Battery via a DC to 115V/400Hz Inverter. Watch the short demonstration video below and you will see the system in action.

Avionics Bending: AC Frequency and Volts Indicators

L-1011 AC Frequency and Volts Meter

The L-1011 Electrical Panel has two instruments that show the AC Frequency and AC Volts measured on a specific subsystem. The image above shows the frequency (left) and AC volts (right) measured directly from the 400Hz Inverter. The instrument on the left indicates 400Hz and the one on the right indicates 115V AC.

Both instruments on the L-1011 had been made by The Lewis Engineering Company which was later acquired by BFGoodrich and closed down in 2000 as a result of the merger. Here is the pinout information for these instruments:

Frequency Meter 152LCF5B

Pin      Function
1        5V AC Lighting (H)
2        5V AC Lighting (L)
3        Chassis Ground
4        115V 400Hz (H)
5        115V 400Hz (L)

AC Volts 152LCV8

Pin      Function
1        5V AC Lighting (H)
2        5V AC Lighting (L)
3        Chassis Ground
4        PMG DC Input
5        115V 400Hz (H)
6        115V 400Hz (L)

Avionics Bending: Voltmeter DC Indicator (Pinout)

The L-1011 Electrical System panel has both a AC as well as a DC voltmeter. The pinout shown here is for the DC Voltmeter.

The instrument shown above is the original Instrument used on the L-1011. However, the way the back illumination worked on the L-1011 electrical and hydraulic gauges caused a lot of yellowing due to heat exposure. Instruments used on Boeing Aircraft like the B747 with the same pinout did not experience that because the illumination of the gauge is significantly different. Below is the B747 instrument using exactly the same pinout:

Here is the pinout:

Pin	Pin Assignment	Value
1	+5V Lighting	0 .. +5DCV
2	Instrument Lighting GND	GND
3	Instrument Casing GND	GND
4	DC Source GND	GND
5	DC Source	0 .. +40VDC

L-1011 Electrical: Emergency Light Switch (24-39)

The Emergency Lighting System Switch is a guarded three-position toggle switch which controls emergency lighting for Flight Station Escape Hatch, Cabin Exits, Cabin Aisle Lights and Emergency Evacuation Slide Areas.

When switch is in the OFF position, the automatic function of all the emergency lights is disarmed and the UNARM light will be illuminated.

All Emergency Lights are illuminated when the switch is in the ON position. An UNARM light illuminated anytime the switch is not in the ARM position.

When the switch is in the armed position, the Emergency lights are armed to illuminate automatically if DC Essential Bus failure is detected, the pilot must manually reset the switch by switching it off and back to the ARM position.

L-1011 Electrical: Light Panels (24-37)

The remaining four types of panels are the:

Two Front Panel Light Controls on the Pilots' front panel or glare shield, for instrument lighting.
The Center Console and Engine Instrument Light Controls to the left of the center console.
The Flight Engineer's Lights Panel located to the lower left of the F/E Panel controls F/E Panel lighting as well as the circuit breaker lighting. 

L-1011 Electrical: Light Panels on Overhead (24-37)

Ten lighting panels are in the Flight Station. Six are found on the Pilots' Overhead Panel.

• Center Console Floodlights
• Overhead Panel Lights.
• Instrument Standby Lights.
• Exterior Lights. 
• Emergency Lights.
• Interior Lights.

L-1011 Electrical: Exterior Lights Overview (24-36)

This is an overview of the Exterior Lights. When all the lights on the external panel are turned on, the panel would look like the shown in the picture. Normally, in flight, the wing flood lights and the wheel well lights would not be illuminated and their switch lights would be off. This would be consistent with the basic L-1011 philosophy that says: when operating under normal circumstances, the pilots' overhead panel will be dark.

As you can see, the exterior lights provide adequate illumination for all operations on the ground and in flight. The lights shown here are:

• Left and Right Wing Landing Lights. 
• Nose Wheel Landing and Taxi Lights. 
• Runway Turnoff Lights.
• Logo Lights.
• Position Lights.
• Strobe Lights.
• Anti-Collision Lights.
• And the Wing Flood Lights.

L-1011 Electrical: Lights (24-34/35)

The lighting system of the L-1011 was very advanced for it's time. Adequate lighting is available for each interior area oft he aircraft where personal would have a need to see, both on the ground and in flight.

The L-1011 has lighting in the following areas:

• Flight Deck
• Passenger Cabin and Galleys
• FESC
• ECS
• Wheel Well
• Forward Cargo
• MESC
• Hydraulic Service Center
• Aft Cargo

Fluorescent lights or incandescent lights are used as required. The emergency system uses incandescent lights as do most of the exterior lights.

The panel to control the Exterior Lights is located on the pilots' eyebrow panel. All of the exterior lights are AC powered except the emergency lights which have separate battery packs. 

L-1011 Electrical: Single Generator and Overload Protection (24-32/33)

Should all but one generator fail, the remaining generator will suddenly be carrying all the electrical load, which would possibly cause its failure if left unattended. In this situation system voltage will begin to drop and on board systems will behave erratically or will fail all together. 

To protect the generator, the galley power and the AC hydraulic pumps are tripped off within one second. This reduces the maximum possible aircraft load to less than 81 KW, or to what a single generator can handle.

Although the three galley power switches are latched in, all three off lights are illuminated. If either or both AC hydraulic pumps were on, they are powered down and their ON legend will extinguish. After the overload condition has ceased, the Flight Engineer may selectively reset any or all oft he galley busses keeping in mind the generator limitations.

L-1011 Electrical: Two Generator Dispatch (24-31)

Automatic load monitoring will occur and shed nonessential high electrical load items to proceed an AC electrical source from an extended over current condition.

Since we have this auto load monitoring, it is possible to dispatch the TriStar with one generator inoperative and no electrical load monitoring necessary. The total aircraft electrical load will exceed the maximum load on a single generator but it is well within two generator capability (which is roughly 150 KW). 

L-1011 Electrical: Galley Power (24-29)

Galley power is on when he switches are latched in and the OFF legend is dark. Galley power accounts for one-half of the aircraft's electrical load.

As long as the galley power switches on the electrical panel are latched in, power is available to the individual galley complexes. Wired in series with the flight engineer's galley power control switches are switches located at each galley. Should a flight attendant wish to turn off power to a galley they simply latch in the switch in the galley and power down the galley.

Galley bus number 1 powers the mid galley, bus number 2 powers the forward galley and bus number 3 powers the aft galley. Yes, coffee makers and ovens need a lot of power. 

L-1011 Electrical: Standby Power to ON (24-27)

Placing the standby power switch to the ON position will complete the circuitry to power both AC and DC standby busses from the batter, regardless of other power sources that are available.

L-1011 Electrical: Pilot Controlled Standby Power (24-26)

Standby power is automatically transferred to the battery if a failure occurs. However, the pilots may also manually control standby power by means of a switch located on the pilots' overhead panel.

Next to the switch is an amber light that warns if the standby power switch is unarmed.

L-1011 Electrical: Battery Powering AC and DC Standby Busses (24-25)

Should essential power fail, the battery is capable of powering both standby power busses.

The battery provides DC power directly the DC standby bus and, by means of an inverter, AC power to the AC Standby Bus.

A fully charged battery will provide power to both standby busses for approximately 40 minutes, minus 5 minutes for every unsuccessful APU start attempt.

L-1011 Electrical: Standby Power (24-22)

Standby power is that power that is required to descend the aircraft and land. If the airplane has only standby power, only the following items are powered:

• Captain's Instruments
• Fire Protection and Detection
• Manual Pressurization
• Start Ignition

The DC Standby bus is powered from the the DC essential bus.

One phase of the AC essential bus provides AC standby power.

L-1011 Electrical: Multiple Power Failures (24-21)

To loose essential AC power, and I think is of particular interest to you Ian, it would be necessary to lose Bus 3 and generator #1.

To loose essential DC power it would be necessary to lose the essential Transformer/Rectifier T/R) unit and have the circuit breaker 3F3 open.

As you can see, essential power is well protected in the Lockheed L-1011.

L-1011 Electrical: Essential Power on Bus No. 3 (24-20)

With the essential power selector in the B3 position, bus #3 is providing AC essential power. This is the only position where the APU generator can be used as the source for essential AC power. The former is done via the AC tie bus.

L-1011 Electrical: Essential Power on Generator One (24-19)

Selecting G1 on the Electrical System Panel powers the AC essential bus directly from generator one, again prior to the generator breaker.

L-1011 Electrical: Essential Power on Generator Two (24-18)

With the essential power selector in the G2 position power is taken directly from generator two, prior to the generator breaker.

From this schematic it is easy to see that as long as the generator field relay (GFR) is closed the generator is capable of powering the essential AC bus if selected.