Garmin GNC 420AW Manual

A SERVICE OF

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5 - PROCEDURES

114

190-00356-00 Rev E

If ATC directs you to make a change, recheck each

element again.

Points to Remember for Localizer or VOR-

based Approaches

• ThedefaultfactorysettingallowstheCDIoutput

to automatically switch from the GPS receiver to

the LOC receiver. This may be changed to manual

insomeinstallations.Ifthe“ILSCDISelection” set-

ting is changed to “Manual”, you must determine

whentoselect“GPS”or“VLOC”guidanceduring

theapproach.Remember,“VLOC”isrequiredfor

the ﬁnal course segment from Final Approach Fix

(FAF) to MAP.

NOTE: Installations with certain autopilots, such

as the KAP 140 and KFC225, do not allow auto-

matic ILS CDI switching.

NOTE: GPS level of service annunciations (LPV,

ENR, etc.) are not applicable to the external CDI

(or HSI) when VLOC is active.

• IftheCDI output has not automatically switched

from GPS to ILS upon reaching the FAF, you must

manuallyswitchtotheVLOC receiver by pressing

the CDIkey.Verifythat“VLOC”isdisplayeddirectly

above to the CDI key.

• Automatic switchingof CDIoutputis available

forILS,localizer,SDFandLDAapproaches.Auto-

maticCDIswitchingisnot available for backcourse

approachesorVORapproaches.

• Whenyinganapproachwiththeautopilot coupled,

you must monitor system functions at all times and

verifythattheautopilotandexternalCDI(orHSI)

switchtotheVLOCreceiverwithsufcienttimeto

capture and track the approach course. Switching

to“VLOC”lateintheapproachmaynotprovidethe

autopilot enough time to respond and intercept the

approach course prior to the FAF (depending upon

the performance characteristics of your autopilot and

aircraft). In such instances, you should manually ﬂy

the approach or refer to the documentation provided

with your autopilot.

• WhenanILSorVORapproachisrstselectedor

executed, the frequency is automatically checked.

If the frequency is correct, you will not receive a

message regarding the frequency. If the frequency

is incorrect, you will receive a message and you

mustplacetheILSorVLOCfrequencyintheactive

frequency ﬁeld.

• When flying a localizer-based approach

(otherthan backcourse)with automaticCDI

switching enabled:

1. “GPS” guidance may be used while ﬂying

outbound and on the initial portion of the

procedure turn.

2. “VLOC” guidance is used on the remainder of

the approach from the time you turn inbound

on the procedure turn.

3. The localizer frequency must be active to use

“VLOC” guidance at the MAP. Press the CDI

key to switch back to GPS data when the

missed approach is initiated.

Points to Remember