Honeywell MKXXII Inhibit Switch Functio ns and Selection, Terrain Inhibit, Audio Inhibit Timed

Honeywell

MK XXII EGPWS Installation Manual

2.3.10.3 Inhibit Switch Functio ns and Selection

The Terrain Inhibit and Audio Inhibit functions are optional but it is recommended that one be used to inhibit the system during certain operations. The operator should evaluate the two options together with the Low Altitude Mode function and select the one that best fits his operational requirements. The Low Altitude Mode is also described below for reference.

2.3.10.3.1 Terrain Inhibit

The Terrain Inhibit will inhibit Terrain and Obstacle audio alerts and warnings. It will not deselect the Terrain Display. The switch is a toggle action, which must be pressed to turn ON and re-pressed to turn OFF. The switch lighting must be activated thru the switch contacts. This Inhibit is recommended for corporate transport operations.

2.3.10.3.2 Audio Inhibit (Timed)

The Timed Audio Inhibit will inhibit all audio output for a period of 5 minutes. It will not affect visual alert and warning outputs and will not deselect the terrain display. The switch is momentary and the lamp is illuminated by an output from the EGPWS. This inhibit is recommended for EMS and SAR operations.

2.3.10.3.3 Audio Inhibit (Not Des cribed Above)

The Audio Inhibit will inhibit all audio output as long as it is active. It will not affect visual alert and warning outputs and will not deselect the terrain display. The switch is a toggle action, which must be pressed to turn ON and re-pressed to turn OFF. The switch lighting must be activated thru the switch contacts. This Inhibit is NOT RECOMMENTED.

2.3.10.3.4 Low Altitude Mode

To allow for helicopter operations that require low altitude flight a Low Altitude function is enabled with a switch. This function is designed for flight at low altitude in VFR conditions. When this function is engaged Mode 2 and Mode 4 warning boundaries are significantly reduced and Terrain Advisory look ahead distances are reduced. . Low Altitude operation is defined as operation below 500 feet AGL. There are other circumstances where the use of the Low Altitude Mode is appropriate. Those include operation in a high-density metropolitan environment with high rise buildings, operation below 1250 feet AGL when the GPS is not operational or is providing poor accuracy.

CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 060-4314-225 REV: C SHEET 48