Category 8 – radio altitude input select, Radio altitude input, Decision height discrete input – Honeywell MK VI User Manual
Page 91: Digital radio altitude interface (cat. 8 id 2)

Honeywell
MK VI MK VIII EGPWS Installation Design Guide
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3.10 Category 8 – Radio Altitude Input Select
Category 8 defines the Radio Altitude and Decision Height interface.
3.10.1 Radio Altitu de Input
Appendix E Table 5.3.8 defines the Radio Altitude Types and identifies the first MK VI/MK VIII EGPWS version
in which the option was available (see Effectivity entry).
Appendix E Tables 5.3.8-x, where x is the Radio Altitude Type number, define the format and electrical
interfaces required to support each Radio Altitude Type.
3.10.2 Decision H eight Discrete Input
The Decision Height discrete (J1-33, Category 8) indicates to the MK VI/MK VIII EGPWC whether the aircraft is
above or below the selected Decision Height.
This discrete is typically connected to the Decision Height output on the Radio Altimeter indicator. If the
‘Minimums-Minimums’ callout is not wanted the Decision Height discrete should be left open.
3.10.3 Digital Rad io Altitude Interface (Cat. 8 ID 2)
21
4
J2
Radio Altimeter R/T
A
B
EGPWS MK VI / MK VIII
A
B
ARINC 429
Radio Altitude
ARINC 429
DH Discrete (Gnd)
33
Radio Altimeter Indicator
DH out
J1
Digital-RA.vsd
DH wiper
Vendor Model
Ind. DH
R/T
R/T
Indicator
SCALE
wiper/out
A
B
Collins RAC-870
ALI-55
ARINC 429
P1-R/V
P1-2
P1-3
Honeywell ALA-52A/B
ARINC 429
MP-B2
MP-B3
Honeywell KRA-405B
KNI-415/416
ARINC 429
P1-M/A
P4051-B
P4051-C
NOTE:
The connector pin numbers given in the Table above are to the best knowledge of Honeywell EGPWS engineering. Please
contact the manufacturer’s customer service to confirm your installation.