Flight Management Navigation - FMS Introduction


When first powered, the FMS is in the preflight phase. As a phase is completed, the FMS changes to the next phase in this order:

  1. Preflight
  2. Takeoff
  3. Climb
  4. Cruise
  1. Descent
  2. Approach
  3. Flight complete


During preflight, flight plan and load sheet data are manually entered into the CDU. The flight plan defines the route of flight from the origin to the destination and initializes LNAV. Flight plan and load sheet data provide performance data to initialize VNAV.

Required preflight data consists of:


Optional preflight data includes:


Each required or optional data item is entered on specific preflight pages.

Preflight starts with the IDENT page. If the IDENT page is not displayed, it can be selected with the IDENT prompt on the INIT/REF INDEX page. Visual prompts help the flight crew select necessary CDU preflight pages. Preflight pages can be manually selected in any order.

After the necessary data on each preflight page is entered and checked, push the lower right line select key to select the next preflight page. When ACTIVATE is selected on the ROUTE page, the execute (EXEC) light illuminates. Push the EXEC key to make the route active.

Use the Departure/Arrival (DEP/ARR) page to select a Standard Instrument Departure (SID). Selection of the SID may cause a route discontinuity in the flight plan. The modification must be connected to the existing route and executed. This can be accomplished on the ROUTE or LEGSpage.

When all required preflight entries are complete, PRE-FLT COMPLETE is displayed on the TAKEOFF REF page.


The takeoff phase starts with engagement of takeoff thrust on the MCP and extends to the thrust reduction altitude where climb thrust is normally selected.


The climb phase starts at the thrust reduction altitude and extends to the top of climb (T/C) point. The T/C is the position where the airplane reaches the cruise altitude entered on the PERF INIT page.


The cruise phase starts at the T/C point and extends to the Top of Descent (T/D) point. Cruise can include step climbs and en route descents.


The descent phase starts at the T/D point or when the VNAV descent page becomes active. The descent phase extends to the start of the approach phase.


The approach phase starts when intercepting the first leg of a published approach selected from the ARRIVALS page.

Flight Complete

Thirty seconds after engine shutdown, the flight complete phase clears the active flight plan and load data. Some preflight data fields initialize to default values in preparation for the next flight.

FMS Operational Notes