Stores Ref. No.:6TD/7287
Connection:Mc.Murdo red range 24 way, internally D-type 25 way


This indicator presents information regarding attitude in terms of bank and pitch angles in the form of an artificial horizon, plus flight director indicator bead.

The main artificial horizon is formed of a black and white roller blind, which moves around rollers for pitch angle. The rollers are mounted within an overhung carriage which rotates on a spindle for roll angle. At its extremes it displays markers for zenith (straight up) and nadir (straight down), pictured above in stereotypical Lightning zenith position for a vertical climb.

Attitude indicator type F4C main spindle slip rings

Main spindle bearing, with cover removed revealing slip ring electrical connections to the roller blind motor and synchro.

The flight director bead is positioned by two stainless steel wires, strung tightly across the front of the indicator. These wires are held by small carriages at their ends which slide across in pairs to position the wire and bead vertically and horizontally.

There is also an orange window which is internally covered over by a solenoid actuated shutter to indicate power health. The orange window is illuminated as per the main display area.

The main display area is illuminated by 4 bulbs, via red acrylic / Perspex.

The motors are quadrature phase type, and angle feedback is via synchro control transmitters for pitch and roll, and precision potentiometers for the flight director bead position.


The indicator includes a large complex vintage electronics module, which I unfortunately have no information on, and reverse engineering it would take forever. This module plugs into the indicator chassis via two 25-way D-Type connectors to interface with the motors and synchros.

The plan is to remove the module, as it just plugs in I don't consider theis a modification, ref: preservation, and make my own plug-in module to replace it to drive the motors and read the synchros.

Roll and pitch data is already available in the Flightgear model, so only some simulator programming work in going to be needed for the flight director bead position.

The turn and slip indicator is pureley a ball in a glass tube, and therefore there is unfortunately no way of directly simulating its behaviour


"IFIS" overview:
A.P.3456D, Part 2, Chap 3, A.L.14, May 1969 - Integrated Flight Instrument System - Paragraph 7

F Mk. 3, T Mk. 5 and F Mk. 6 aircrew manual:
A.P.101B-1003, 5 & 6A, Part 1, Chapter 7, A.L.2, Nov 1984 - Instruments - Paragraph 14

T Mk.5 electrical "Vol. 1":
A.P.101B, Sect.7, Chap.3C, A.L.67, May 1975 - Dynamic Flight Reference System - Paragraph 24