Mach/Airspeed Warning System
Two independent Mach/airspeed warning systems provide a distinct aural
warning, a clacker, any time the maximum operating airspeed of Vmo/Mmo is exceeded.
The warning clackers can be silenced only by reducing airspeed below Vmo/Mmo.
The airspeed indicator displays red warning bands indicating maximum and minimum
airspeeds. Amber bands indicate maximum and minimum maneuvering airspeeds.
When either an overspeed condition or a system test occurs, the ADIRU transmits a signal
to the aural warning module, sounding the clacker.
The system can only be tested on the ground.