B. zero feet offset, B. zero feet offset -4 – Honeywell KA 54 User Manual

Page 30

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KRA 405B RADAR ALTIMETER INSTALLATION MANUAL

Page 2-4

006-10536-0010 Rev. 10

Oct/2005

The Editing window will be removed and the Memory Definitions window

will again be displayed, to allow further changes, and the Main

screen will display a message describing the changed parameter.

After completing the all changes to the settings, refer to the KPA

900 Operators Guide P/N 006-05392-00XX for instructions to complete

the programming of the Configuration Module.

Honeywell recommends that the programmed module be verified before

installation. Exit the KPA 900 program, re-invoke it, read the

programmed module, and verify the correctness of the settings. This

step will ensure that the programming operation was successful.

B.

ZERO FEET OFFSET

The KRA 405B Receiver/Transmitter DOES NOT require an Aircraft

Installation Delay (AID). The KRA 405B R/T has provisions to

calibrate to zero feet during the installation. After this

calibration, the KRA 405B will provide a radar altitude of basically

zero feet (see note below) when the aircraft is taxiing or

stationary on the ground.

NOTE:

All versions of the KRA 405B with 01/03 or 02/03 software

and -2001/-4001 version units with 01/03 or higher soft-

ware may provide slight negative values of altitude when

the aircraft is taxiing or at rest. This is normal oper-

ation as the altitude calculation may vary around zero at

plus and minus the system accuracy. All other unit and

software configurations will "clamp" negative calculation

results to zero feet, and never go negative. The config-

uration module supplied offset is applied to the altitude

data after the "clamp", so all unit configurations have

the capability to produce negative results.

The Honeywell EFIS 40 and EFIS 50 systems (and possibly

other systems) will not display negative altitudes re-

ceived on the digital bus. When the Honeywell EFIS detects

a negative altitude value, it "declutters" or blanks the

altitude information from the displays. The EFIS will

also rebroadcast incorrect Radio Altitude information on

the general-purpose bus.

All versions of units with 01/03 or 02/03 software and

-2001/-4001 version units with 01/03 or higher software

must not interface to the EFIS 40 or EFIS 50 systems via

the ARINC 429 bus. All flavors and software versions of

he KRA 405B must not be configured with a zero foot offset

when interfacing the EFIS via the digital bus. Interfaces

via any of the analog outputs will function correctly.

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