> For the complete documentation index, see [llms.txt](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/system-descriptions/electrical-systems/electrical-power/multipurpose-equipment.md).

# Multipurpose Equipment

The multipurpose equipment provides a junction location for airframe and engine systems. It consists of the relay panel.

## Relay panel

The relay panel serves as the mounting bracket for the IDLE/FLY, START, IGNITION, XOT HOT, XOP LOW, FUEL LOW, CRANK, and FANS relays, a terminal block rail, the connector to the engine and airframe systems, and the Engine Control Unit (ECU) test connector. It is located on the avionics shelf.

## Operation

Refer to [Engine Control](/bell-505-maintenance-guide/system-descriptions/power-plant-systems/engine-control.md) for the operation of the IDLE/FLY, START, XOT HOT, XOP LOW, FUEL LOW, and CRANK relays.

Refer to [Ignition](/bell-505-maintenance-guide/system-descriptions/power-plant-systems/ignition.md) for the operation of the IGNITION relay.

Refer to [Avionics Fans](/bell-505-maintenance-guide/system-descriptions/airframe-systems/environmental-control/avionics-fans.md#operation) for the operation of the FANS relay.

Refer to [Transmission Indicating](/bell-505-maintenance-guide/system-descriptions/main-rotor-drive/main-rotor-drive-indicating.md#transmission-indicating), [Freewheel Indicating](/bell-505-maintenance-guide/system-descriptions/main-rotor-drive/main-rotor-drive-indicating.md#freewheel-indicating), and [Oil Indicating](/bell-505-maintenance-guide/system-descriptions/power-plant-systems/oil.md#oil-indicating)  for the operation of the terminal block rail.

Refer to [Engine Control](/bell-505-maintenance-guide/system-descriptions/power-plant-systems/engine-control.md) for the operation of the ECU test connector.