CREW
AWARENESS
AIRPLANE
OPERATIONS
MANUAL
2-04-30
Page
20
Code
01
REVISION 38
AOM-145/1114
MODE 5 - EXCESSIVE DEVIATION BELOW GLIDESLOPE BEAM
Mode 5 provides two levels of alerting if the airplane's flight path
descends below the glideslope on ILS approaches.
Minimum Terrain Clearance (MTC) for "GLIDESLOPE" message
triggering:
− Minimum:
− For the Soft Alert Area, 30 ft at 2.98 dots of glideslope
deviation.
− For the Hard Alert Area, 30 ft at 3.68 dots of glideslope
deviation.
− Maximum:
− For the Soft Alert Area 1000 ft.
− For the Hard Alert Area 300 ft.
The first alert occurs whenever the airplane is more than 1.3 dots
below the beam and is called a "soft alert" because the volume level is
reduced. A second alert occurs below 300 ft radio altitude with greater
than 2 dots deviation from glideslope and is louder or "hard".
The aural message "GLIDESLOPE" is sounded once. Follow-on alerts
are only allowed when the airplane descends lower on the glideslope
beam by approximately 20%. Aural messages are sounded
continuously once the airplane exceeds 2 dots.
The "GPWS" warning message is displayed on EICAS for airplanes
equipped with GPWS and the amber "GND PROX" indication on the
PFD for airplanes equipped with EGPWS.
The glideslope warning can be canceled by pressing the Master
Caution Button.
To Next Page
