TM 1-1510-218-10
3C-118
the FAF or any other waypoint. The FMS will
immediately resume FMS course guidance.
j. Alternate Flight Plan Overview. The
alternate flight plan is a complete plan for a mission or
a mission segment that includes a route of up to 60
waypoints, with calculations of courses, distance, time,
gross weight, and fuel requirements including reserve
allocations. It includes standard flight planning data
and provides an electronic hard copy of the flight plan
in the FMS-800 that may be modified at any time.
Forty alternate flight plans may be stored on the
data cartridge from either an MPGS or laptop facility,
or by manual entry via the CDU on the aircraft. One
alternate flight plan at a time may be selected and
transferred into the CDU for viewing and the
operations are described in this section. This alternate
flight plan is separate from the active flight plan and
does not sequence or change unless the crew
modifies it. It can be transferred or added to the active
flight plan, Paragraph 3C-25.e, and the alternate flight
plan will remain intact.
The alternate flight plans stored on the data
cartridge are not automatically updated with new
waypoint data whenever a new primary ICAO
database is loaded onto an FMS data cartridge. With
each ICAO database update, each alternate flight plan
should be updated at a ground station (outdated
waypoints replaced with current ICA O definition), and
the on-aircraft FMS purged of existing flight plans.
The updated alternate flight plans can then be used for
normal operations.
(1) Alternate Flight Plan Structure. The
alternate flight plan operates as a spreadsheet
calculator. The crew inputs the flight plan routing,
wind, and aircraft performance. The FMS-800
calculates the individual leg data as well as the flight
totals. Vertical scrolling on the CDU accesses the legs
of the plan (1 through 60). Complete data for each leg
is accessed by lateral scrolling among leg pages with
suffixes A, B, and C. Refer to Figure 3C-64 and Table
3C-47.
The Alternate Flight Plan Waypoints page
presents the alternate flight plan in a format similar to
the active flight plan, Figure 3C-64. Modify the
alternate flight plan on this page in the same manner
as the active flight plan.
(2) Alternate
Flight
Plan
Access
and
Transfer. On the Alternate Flight Plan page, various
top-level access and transfer options are offered to the
crew. Refer to Figure 3C-65 and Table 3C-48. When
an alternate flight plan is transferred or added to the
active flight plan, only the sequence of waypoints and
the following waypoint attributes are transferred: All
others are calculated by the FMS-800 using sensed
data rather than the planned parameters of the
alternate flight plan.
(a) Wind for each leg.
(b) Altitude
for
each
waypoint
(if
assigned).
(c) The time associated with the last
entered time of arrival.
(d) MFP for each waypoint (if assigned).
