(b)
The GND PROX G/S INHB light/switch can be pressed to inhibit the aural and visual mode 5 alerts.
(6)
Mode 6 Function (Fig. 2)
(a) Mode 6 provides a voice at selected radio altitudes and/or barometric altitudes to advise the flight crew of the approximate radio altitude. Mode 6 can also provide a bank angle alert that gives the aural BANK ANGLE, BANK ANGLE message if the airplane's bank angle exceeds the limits defined within the EGPWC.
The radio altitude callout function is armed when the airplane is above 1000 feet radio altitude while in the approach mode or the airplane transitions from takeoff to approach mode. Each radio altitude aural callout is generated once while descending through the corresponding radio altitude band. Once the aural is called out, or its associated altitude band is transitioned, it will not function again until the airplane satisfies the above conditions to arm the radio altitude callout function. If two or more radio altitude callout bands are transitioned before the callouts can be issued, only the lowest altitude is called out.
There are no visual alerts associated with a Mode 6 alert. Different alert callouts can be set by EGPWC program pins.
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(7)
Mode 7 Function (Fig. 2)
(a)
Mode 7 warning signals are provided when flying into an excessive windshear condition during takeoff or approach. If an excessive downdraft or tailwind condition is detected, a two tone siren followed by an aural WINDSHEAR, WINDSHEAR, WINDSHEAR warning is heard. A red WINDSHEAR message is displayed on the captain's and first officer's PFD, and the red master warning light comes on. When the windshear warning is active, all other EGPWS modes are inhibited. These modes stay inhibited as long as there is an excessive windshear condition.
(b)
Aural messages are prioritized; windshear warnings take priority over all other ground proximity warning system alerts.
(8)
Envelope Modulation
(a) The EGPWC envelope modulation feature provides improved alert and warning protection and reduces nuisance warnings at specific locations throughout the world.
(9)
Terrain Clearance Floor (Fig. 2)
(a) The Terrain Clearance Floor (TCF) feature creates an increasing terrain clearance envelope around the intended destination airport runway directly related to the distance from the runway. The Runway Field Clearance Floor (RFCF) similarly creates an increasing terrain clearance envelope around the intended destination runway, but specifically for those airports in which the runway elevation is higher than the adjacent terrain below the flight path. TCF alerts are based on current aircraft location, nearest runway center point position, and radio altitude. RFCF alerts are based on current aircraft location, runway center point, and height above the runway. TCF and RFCF are active during takeoff, cruise, and final approach. These alerts complement the EGPWS Mode 4 protection that provides an alert based on insufficient terrain clearance even when in landing configuration.
If either the TCF or RFCF envelopes are entered, the aural message TOO LOW TERRAIN, TOO LOW TERRAIN is heard and an amber TERRAIN message is displayed on the navigation display (ND). After that, a single TOO LOW TERRAIN message is heard every time the radio altitude decreases by 20 percent. If the descent continues, the aural message PULL UP is heard, a red TERRAIN message is displayed on the ND, the red PULL UP indication shows, and master warning lights come on. The EGPWS warning messages show until the aircraft exits the alert envelope.
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(10) Terrain Awareness Alerting and Display (Fig. 2)
(a) The Terrain Awareness Alerting and Display (TAAD) functions (terrain awareness alerting function and terrain awareness display function) predict potential conflicts between the aircraft flight path and terrain by providing a graphic display of terrain ahead. These functions use geographic position, aircraft altitude, and a terrain database to predict potential conflicts between the aircraft flight path and the terrain, and to provide graphic displays of the conflicting terrain. 1) The terrain awareness alerting algorithms continuously
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