The RAC RP4 LED Position Indicator is a cockpit-mounted servo position display used in aircraft trim and control surface systems to show the exact position of a connected actuator (such as an aileron trim or servo system).

It uses a 10-LED linear display with additional amber reference LEDs at both ends, providing a clear visual indication of actuator travel. The unit is typically paired with Ray Allen or compatible servo systems and is installed directly into the instrument panel.

The RP4 is designed for high visibility in daylight conditions while also being dimmable for night operation. It is commonly used in experimental and light aircraft for monitoring aileron, elevator, rudder, or flap trim positions, depending on configuration.

It is a direct replacement for earlier RP3 units and uses a compact panel mount design with standardized wiring for aircraft servo systems.

Key features include:

RAC part number: RP4 (Aileron indicator version)
10-LED linear position display
Additional amber reference LEDs on both ends
Compatible with trim servo systems (aileron, elevator, rudder, flaps)
Panel-mounted cockpit instrument
Bright daylight-readable display
Dimmable for night flying
Direct replacement for RP3 indicator
Compact faceplate: ~45 mm × 19 mm
Designed for Ray Allen / compatible servo systems
Used in experimental and light aircraft control systems
Indicates real-time actuator or surface position