Original Fligth Hardware: NAV Radio Heads

The Lockheed L-1011 uses two VHF NAV radio heads that are mount to the left and to the right of the autopilot system on the glareshield (see location image at the end of the posting). The panel above shows a version of the VHF NAV panel that has "AUTO TUNE" capability. When the radio is in auto tune mode, the FMS can tune the NAV frequency, however the frequency will not be shown on the head the number will simply be overlaid by a flag labeled as "AUTO".

The image below, shows a dual NAV head that is used by Boeing aircraft, such as the Boeing 747. I am actually, contemplating using the B747 style head for my L-1011 project, because the head is easier to interface with.


Both, the single and the dual NAV heads cover a frequency range from 108.00 MHz to 117.95 MHz (which is the typical NAV radio frequency range used for at least the last 30+ years). Both heads have a rotary switch that switches the following functions:

• STBY ... Receiver operational but not transmitting. four dashes will appear on the RDDMI and shows that there is no computed data for distance.
• NORM ... enables the DME to be usable up to 200 NM
• OVRD ... enables the DME to be somewhat usable to 400 NM
• TEST ... DME fail flag followed by four dashes followed by four zeros in the RDDMI DME window.

The AUTO/MNL switch alternates the VHF NAV head been manual input made by the frequency selector as shown in the frequency window, or automatic tuning as instructed by the flight management system (FMS).


Panel Location

Original Flight Hardware: VHF COMM Radio Head

For the communications equipment on my Lockheed L-1011 project I have picked Gables Electronics radio heads. The heads are simply frequency selectors for the VHF frequency range of 118.00 MHz to 136.97 MHz.



The head uses a two drum-style digit displays that are backlit and are each driven by the respective two-element selector switch. The big rotating knob on the bottom of the two element stack controls the digits to the right of the decimal point. The smaller one on top controls the digits to the left of the decimal point.

The TFR switch points to the active frequency and renders the other one the stand-by frequency. The active frequency selection is also indicated by a green illuminated dot.


Panel Location

Original Flight Hardware: Central Electronics Complex

So, the assembly of components above is somewhat my first approach to the instrument heads found on the L-1011 pedestal. These instruments would be located right after the throttle quadrant. What is not shown in the picture are the trim instruments that are also part of the center pedestal.



The image below shows the location for the Communications radios using the VHF band. They are identified as VHF1, VHF2 and VHF3. I added a 4096 Transponder to it and the head for the WX Radar. The WX Radar panel is actually a Boeing 747 WX Radar controller. I included two Navigation radios (labeled NAV1 and NAV2). In the bottom right hand corner I have a dual ADF radio head. There is an amplifier/radio selector for the pilot and the first officer.



The next two images show how the individual radio heads could be cabled into the selector panels for both the captain and the first officer.