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. 

Avionics Bending: ATM Tach Indicator (Pinout)

The L-1011 has an Air Turbine Motor (ATM) that can directly pressurize the B and C Hydraulic systems. The indicator shown in this pinout displays the RPM of the ATM and is located on the L-1011s' Hydraulic System panel:

Below is the schematic for the ATM Tachometer Indicator:

Below is the pinout summary:

Pin 1: 5V AC Lighting
Pin 2: 5V AC Lighting
Pin 3: RPM Level in +
Pin 4: RPM Level in -
Pin 5: Chassis Ground

L-1011 Flight Controls: RAT Power (27-11)

Additional system redundancy is provided through the Ram Air Turbine (RAT) automatically; or manually, powering the B system.

The RAT automatically deploys with all six, 4 engine-driven and two ATMs, hydraulic pumps turned off or all three engine N3 RPMs below the minimum flight condition or flight idle. The RAT can be manually deployed with the deploy switch on the flight engineer Hydraulic Panel.

Here are the flight controls powered by the B system through the RAT:

• Rudder - with 1 large actuator 
• Stabilizer - with 1 actuator 
• Ailerons - all four ailerons are powered 
• Spoilers - only spoilers 1, 4 and 6 on both wings

L-1011 Flight Controls: Surface Hydraulic Systems (27-10)

The L-1011 has four (4) hydraulic systems that operate the individual surfaces. Hydraulic pressure is provided as follows:

• The Number 1 Engine drives the A hydraulic system.
• The Number 2 Engine drives the B and C hydraulic systems.
• The Number 3 Engine drives the D hydraulic system. 

The Rudder receives hydraulic pressure from three different systems: A, B and C
The Stabilizer receives hydraulic pressure from all four hydraulic systems: A, B, C, and D

The Ailerons are driven by different hydraulic systems depending on their location along the wing:

Inboard Ailerons us 3 systems. On the left hand side they use systems A, B and C and on the right hand side they use systems B, C and D. For the outboard ailerons on the left hand side we use system A and B and on the right hand side systems B and D.

The Flaps and Slats are powered by two systems: A and C

The hydraulic systems for the Spoilers are rather diverse:

• No.1 Spoiler Limiter System - B system.
• No.2 and 3 Spoiler Limiter System - D system.

Left Wing

• No. 1, 4 and 6 Spoiler - B system
• No. 2 Spoiler - A system
• No. 3, 4 and 5 Spoiler - C system

Right Wing

• No. 1, 4 and 6 Spoiler - B system
• No. 2 Spoiler - D system 
• No. 3 and 5 Spoiler - C system

Note that the No. 2 spoilers are the odd power sources relating to their wing engines.

Avionics Bending: Hydraulic Pressure Indicator - Pinout

There are four Hydraulic Pressure Indicators in the cockpit of the L-1011. The indicator is a moving coil indicator. The indicators used in the L-1011 are made by the Thomas A. Edison Instrument Division and have a model number of 80099-458-01400.

The schematic below is an excerpt from a larger hydraulic system schematic, it shows the Hydraulic Pressure instrument on the left hand side. It is powered by one of the system buses and acts as the power source for the transmitter on the right hand side of the schematic.

Here its the pinout for the Thomas A. Edison Instrument Company Hydraulic Pressure Indicator:

Pin 1: Instrument Lighting 5VDC

Pin 2: Instrument Lighting GND

Pin 3: Not Used

Pin 4: Moving Coil (Hi)

Pin 5: Moving Coil Pointer

Pin 6: Moving Coil (Lo)

Pin 7: BITE Test Output

Pin 8: Not Used

Pin 9: Not Used

Pin 10: Instrument Case Ground

Pin 11: 115VAC 400Hz Power In (Hi)

Pin 12: 115VAC 400Hz Power (Lo) Ground

L-1011 General Aircraft Characteristics: Basic Flow Bar Philosophy (25-27)

Flowbars, when lighted, complete panel schematics. There are basically two types of flowbars. Those that represent switch position and those that represent valve or relay position.

The systems that use fluids such as hydraulics and fuel systems are good examples for flowbars which indicate switch position.

Other systems such as pneumatics and electrical are good examples of flowbars which indicate valve or relay position.

Original Flight Hardware: Hydraulic System

Hydraulic power, on the Lockheed L-1011, is used for operation of the flight controls, landing gear, nose gear steering and main gear brakes. The power is furnished by four separate hydraulic systems. The image below shows the Hydraulic System as I have re-assembled today (1/3/2010) - the instruments for the A and the B system are still missing.


The four hydraulic systems are designated as A, B, C and D. Which can be seen in the picture below.


Systems A and D are normally pressurized by single hydraulic pumps driven by engine #1 and engine #3 respectively. Additionally, they can be pressurized by systems B and C thru Power Transfer Unites (PTUs), however, there is no fluid transfer from one system to the other.

System B and C are normally pressurized by respective hydraulic pumps driven by engine #2. The pressurization systems are:

• A1 .. pump driven by engine #1
• B1 .. pump driven by engine #2
• B2 .. pump driven by ATM
• B3 .. pump driven by AC motor
• C1 .. pump driven by engine #2
• C2 .. pump driven by ATM
• C3 .. pump driven by AC motor
• D1 .. pump driven by engine #3
• B-A .. pressurization by PTU
• C-D .. pressurization by PTU

The image above shows the alternative pressurization methods for system B and C which are: RAM Air Turbine (RAT) and the two AC powered electrical pumps.

The image below shows the two Air Turbine Motor systems that can further be used to augment the pressurization of the B and C hydraulic systems. The ATMs are driven by bleed air from the pneumatic system and can be engaged automatically, manually or disabled. There is a separate lubrication reservoir for each ATM with an annunciator showing HI TEMP and/or LO PR for the lubricant.

The rotary switch for the ATM is in a locked position when in the OFF position. The ATM system has an over-speed test position called "OVSP TEST". Turbine RPM can be read from the RPM instrument.

In the image below, the red line indicates the primary system operation for the "C" hydraulic system as driven by the ENG2 hydraulic pump. The orange line indicates the alternate fluid path through the ATM that allows to C system to be pressurized via the pneumatic system. The blue line shows the primary system operation for the "D" hydraulic system as driven by the ENG3 hydraulic pump. The purple line indicates the alternate system pressurization via the Pressure Transfer Unit (C-D) from the "C" hydraulic system.


Below the third methods of pressurizing the "B" and "C" hydraulic systems. The red line shows "B" system pressurization via the RAM Air Turbine (RAT) and the orange line shows "B" system pressurization via the B3 AC Electric pump. The blue line shows system "D" pressurization via the D3 AC Electric pump. Of course, both systems again are able to pressurize the "A" (via the B-A PTU) system as well as the "D" (via the C-D PTU) system.




Panel Location