Description (AMM 34-62-01)

 

A- The Flight Management Computer System (FMCS) is one of five major subsystems of the Flight Management System (FMS). The other four major subsystems are: the Digital Flight Control System (DFCS), the autothrottle System (A/T), the Inertial Reference System (IRS) and the Electronic Flight Instrument System (EFIS).

 

B- The FMCS provides the functions of navigation, lateral guidance (LNAV), vertical guidance (VNAV), flight planning, and optimizes airplane performance. These functions assist the pilot with the flight management and control of the airplane.

 

C- The FMCS allows the operator to preplan an entire flight. These procedures are simplified by FMCS integration of navigation, guidance, and performance management functions. In conjunction with other FMS components, the FMCS provides automatic lateral guidance, vertical guidance and speed control (within constraints of air traffic control). The flight preplan function allows a route to be preplanned from origin to destination. The preplan is from data stored in the navigation data base.

 

The FMCS calculates minimum cost flight profiles for climb, cruise and descent, which may be used by the DFCS and the A/T for automatic flight control through the LNAV and VNAV modes. In addition all computed values are displayed to aid the pilot in flying the optimum profile using manual control.

 

D- A single Flight Management Computer System (FMCS) is installed in the airplane. The FMCS consists of three units: two Control Display Units (CDUs) and one Flight Management Computer (FMC) (Fig. 1).

 

(1) The control display units are located on the pilots forward control stand electronic panel (P9).

 

(2) The flight management computer is located on the E-1 rack in the main equipment center.

 

E- Principle airplane systems and indicators that are connected to the FMCS are listed below:

(1) Engine Bleed Air Compression Control System (Chapter 21-11)

(2) Autopilot/Flight Director System (Chapter 22-11)

(3) Autothrottle System (Chapter 22-31)

(4) Digital Stall Warning System (Chapter 27-32)

(5) Fuel Quantity Indicating System (Chapter 28-41)

(6) Wing Thermal Anti-Icing System (Chapter 30-11)

(7) Air Data Pressure Instruments (Chapter 34-12)

(8) Electronic Flight Instrument System (Chapter 34-22)

(9) Inertial Reference System (Chapter 34-28)

(10) VOR/ILS Navigation System (Chapter 34-31)

(11) Ground Proximity Warning System (Chapter 34-42)

(12) DME System (Chapter 34-55)

(13) Nose Cowl Anti-Icing (Chapter 75-11)

(14) Variable Bleed Valve System (Chapter 75-32)

(15) Engine Tachometer System (Chapter 77-12)

 

F- The CDU permits the operator to select the operating modes of the FMCS. The Alternate Navigation Control Display Unit (ANCDU); when installed, has the additional capability to function as an independent source of navigation. In this mode the CDU provides lateral navigation, as an alternate source to the lateral navigation from the FMC. A navigation select switch enables the captain, or first officer, to select the FMC, or the CDU, as the source of lateral navigation.