The indicating system supplies output signals to give indication on the condition of the pneumatic system and its related components.

The indicating system gives indications on the parameters that follows:

• The bleed air pressure in the ducts
• The position of most valves in the pneumatic system
• Leaks in the pneumatic system ducts
• Too hot condition in the bleed ducts, the anti-ice ducts and piccolo tubes, and the APU ducts

These parameters are shown on the engine indication and crew alerting system (EICAS) display, on the glareshield, and on the overhead panel.

Indicating for the pneumatic system components is supplied by the components that follow:

• Two bleed management controllers (BMCs)
• Temperature sensors
• Pressure sensors

The BMCs are found in the avionics bay. One BMC controls the left bleed supply system, the other BMC controls the right bleed supply system. The BMCs are connected to the EICAS system which, in usual conditions, shows the condition of the pneumatic system through the EICAS secondary display. In there is an incorrect condition, the failure indication is shown on the EICAS primary page.

The temperature and pressure sensors transmit the indication signals to the BMCs. The BMCs then, transmit the applicable output signals to show the indications on the EICAS.

Switch, lights and aural warnings also give indication when there is a leak.