Garmin gnc 420 用户指南

GNC 420/420A Pilot’s Guide and Reference

3-27

With the profile set, the vertical speed required (VSR) 

is displayed on the Vertical Navigation Page.  Expect the 
following  to  occur  when  using  the  vertical  navigation 
feature:

•  At one minute prior to reaching the initial descent 

point, a message ‘Approaching VNAV Profile’ 
occurs.  The descent (or climb) angle also locks to 
prevent changes in speed from altering the profile.

•  If selected, the vertical speed required (VSR) 

readout on the Default NAV Page and the Map 
Page show the desired vertical speed to maintain 
the proper descent (or climb) angle.

•  At 500 feet above (or below, for a climb) the target 

altitude, an ‘Approaching Target Altitude’ message 
is provided.  The VSR readout on the Default NAV 
Page and the Map Page is blanked out, at this 
point.

Vertical navigation messages can be turned on or off, 

they are off by default.  Turning the messages off allows 
the  pilot  to  keep  the  previous  profile  settings,  without 
having  them  generate  messages  when  the  feature  is  not 
needed.

1)  Press  the  MENU  Key  to  display  the Vertical 

Navigation Page Menu (Figure 3-54).

2)  With  ‘VNAV  Messages  On?’  highlighted, 

press the ENT Key.  Or, if the messages are 
already on, to turn them off, make sure ‘VNAV 
Messages Off?’ is highlighted and press the 
ENT Key.