Table of Contents
Advertisement
Flight Management System (FMS) for the Agusta AW139/AB139 Helicopter
VNAV LATE PATH DESCENT (VPATH)
A VNAV late path descent is shown in Figure 7--25.
The VNAV late path descent scenario occurs when ATC has not given
descent clearance by the time the TOD is reached. The steps are as
follows:
An altitude constraint is entered at a waypoint (1). The FMS
D
calculates an angle and TOD (2) for the path descent.
One minute before reaching the TOD, the vertical deviation scale is
D
displayed on the EFIS. When the altitude preselector is not at a
lower altitude, the message RESET ALT SEL? is displayed.
When past the TOD and more than 500 ft above the path, the flight
D
guidance computer remains in VALT.
The altitude preselector is set (4) to the ATC cleared altitude.
D
The IAS button (5) is pushed to begin descent. When the aircraft is
D
past the TOD but less than 500 ft from the path when the selector
is set lower, the FMS switches directly to VPATH.
The flight guidance computer does a normal level off switching from
D
VPATH to VASEL to VALT (1).
A28- - 1146- - 181
REV 3 Mar 2009
Honeywell International Inc. Do not copy without express permission of Honeywell.
Figure 7- -25
VNAV Late Path Descent
Flight Plan
7-45
Advertisement
Table of Contents
