AS435 Electronic Flight Management Systems

Flashcards from lecture notes on Electronic Flight Management Systems.

What is an FMS?

Electronic Flight Management System

What is aircraft automation?

Using automated systems to control the aircraft.

What is the purpose of autothrottle?

To automatically control the engine thrust.

What is the sole purpose of aircraft autopilot computers?

To zero the error between the desired input and the actual input.

What do control computers have?

Inputs and outputs.

What is the output of a control computer?

An electrical voltage sent to servo actuators.

What are the three main actions performed by the pilot regarding the autopilot?

Engages the autopilot or autothrottle, Selects the modes, Enters the desired quantities

What are the three main actions performed by the computer regarding the autopilot?

Receives the actual inputs from data buses, Determines the error and correction using its algorithm, Sends electronic signals to the servo

What is the purpose of a data bus?

A data bus transfers data between a computer's memory and its CPU.

What is a MIL-STD-1553 multiplex data bus system?

A Bus Controller (BC) controlling multiple Remote Terminals (RT) all connected together by a data bus providing a single data path between the Bus Controller and all the associated Remote Terminals.

What is ARINC?

Aeronautical Radio INC, a private organization promoting standardization of aircraft systems.

What is an algorithm?

A set of commands that must be followed for a computer to perform calculations or other problem-solving operations.

What is the function of servo actuators?

Provide force to move flight controls or simply move levers (like fuel control), Actuate valves that control pressure for flight control surfaces, gear, fuel control, brakes etc.

How does the computer know the actual input position?

The Computer receives feedback from sensors: position sensors tell the position of flight control surface, brakes, fuel controls. Other sensors tell the actual input position: heading, VOR radial, IAS, Mach #, power setting, V/S, altitude

How do servos work?

They receive an electrical voltage, They open or close valves to vent Hydraulic/Pneumatic pressure to move something: Flight control actuator, brakes, fuel control, etc., They run motors to position something: Flap motor example (jackscrew). Could open cargo doors if controlled by computer

What are the three types of computer controlled servo-actuators?

Electrical signals controlling mechanical electric motors, Electrical signals controlling hydraulic valves, Electrical signals controlling pneumatic valves

What are Pneumatics derived from ?

The Latin pneumaticus: from air or wind, From the Greek pneumatikos: of air or breath

What are the three computers in the aircraft associated with autopilot ?

Pitch computer, Roll computer, Autothrottle computer

What are pitch and roll computers called ?

Flight Control Computer (FCC) or Autopilot

What are the three levels of automation ?

FMC via CDU (Control Display Unit),
MCP (Mode Control Panel),
Manual via yoke and rudder pedals

What are the manual levels of automation?

The aircraft is hand flown. The aircraft is hand flown with Flight Director. The autopilot is engaged for hours at a time