Lecture 9 Ground Proximity Warning System (GPWS) Radio Aids & Navigational System.
Ground Proximity Warnig System
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Transcript of Ground Proximity Warnig System
Ground Proximity Warning system
Ground Proximity Warning System (GPWS) is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle. Another common name for such a system is Ground-Collision Warning System (GCWS). More advanced systems, providing additional protection, are known as Enhanced Ground Proximity Warning Systems (EGPWS).
The EGPWS provided by Flight Gear emulates the MK VIII made by Honeywell Inc. It provides all inputs and outputs of the original hardware. Also the configuration categories and their encodings are modeled to match the original equipment.
The system monitors an aircraft's height above ground as determined by a Radio Altimeter. A computer then keeps track of these readings, calculates trends, and will warn the captain with visual and audio messages if the aircraft is in certain defined flying configurations ("modes").
The modes are:
1. Excessive descent rate ("SINK RATE" "PULL UP")
2. Excessive terrain closure rate ("TERRAIN" "PULL UP")
3. Altitude loss after take off or with a high power setting ("DON'T SINK")
4. Unsafe terrain clearance ("TOO LOW – TERRAIN" "TOO LOW – GEAR" "TOO LOW – FLAPS")
5. Excessive deviation below glideslope ("GLIDESLOPE")
6. Excessively steep bank angle ("BANK ANGLE")
7. Windshear protection ("WINDSHEAR")
System Operation:
The main component of the system is the GPWS computer. It receives information from other aircraft system (Baro/Rad Alt Ht, speed, etc.). From these
inputs, the computer makes calculation to determine if the aircraft is in danger of contacting the terrain below. GPWS only operates within the Rad Alt range (50’ to 2500’).
Ground Proximity Warning Computer
The GPWC establishes the limits for the GPWS modes and compares the aircraft’s flight and terrain clearance status against established mode limits. If the aircraft is found to have entered a GPWS mode, the computer issues appropriate warning or alerting signals. The computer also stores failure data in a nonvolatile memory for display on a front panel window on the GPWC
GPWS Control Panel:
The GPWs control panel provides the flight crew with visual indication of GPWS operation; self-test capability and flap/gear inhibit capability
INOP
Amber “INOP” light is illuminated when a computer or input signal malfunction is detected or a GPWS self-test is being performed.
Flap/Gear Inhibit
This switch is a two-position toggle switch guarded and safety-wired in the “normal” position. When it is place in the “INHIBIT” position modes 2,3 and 4 are inhibited.
Self Test Switch
This switch is used to initiate a GPWS self test. A self test can be conducted on the ground or in flight.