What does the outer loop of an autopilot do?

Aeronautical & Aerospace Engineering : Avionics - Quiz(MCQ)

Generate commands for the pilot to follow

Generate commands to the inner flight control loop

Access the flight control surfaces to control the pitch and roll of the aircraft

Access the flight control surfaces to control the altitude and heading of the aircraft

Correct Answer : Generate commands to the inner flight control loop

Explanation : The autopilot exercises a guidance function in the outer loop and generates commands to the inner flight control loop. These commands are generally attitude commands which operate the aircraft’s control surfaces through a closed flight control loop system so that the aircraft rotates about the pitch and roll axes until the measured pitch and bank angles are equal to the commanded angles. The changes in the aircraft’s pitch and bank angles then cause the aircraft flight path to change through the flight path kinematics.

Recently Updated in Avionics Questions

What is the interval for updating data in the navigation database?

1 hour

24 hours

28 days

1 month

Correct Answer : Option (C) : 28 days

Explanation : The navigation database is updated every 28 days, according to the ICAO AiRAC cycle, and is held in non-volatile memory. It is clearly essential to maintain the recency and quality of the database and the operator is responsible for the detail contents of the database which is to ARINC 424 format.

Which one of the following is not a factor for calculating speed breaches by the FMS?

CG position

Aircraft weight

Position of the aircraft

Wind and temperature models

Correct Answer : Option (C) : Position of the aircraft

Explanation : The FMS continually monitors the aircraft envelope and ensures that the speed envelope restrictions are not breached. It also computes the optimum speeds for the various phases of the flight profile. This is carried out taking into account factors such as: Aircraft weight – computed from a knowledge of the take-off weight and the fuel consumed (measured by the engine flow meters), CG position – computed from known aircraft loading and fuel consumed, Flight level and flight plan constraints, Wind and temperature models, Company route cost index.

Which one of the following is not a navigation mode used by FMS for computing position of the aircraft?

Inertial (IRS) – GPS

Inertial (IRS) – VOR/DME

Inertial (IRS) – DME/DME

GPS only

Correct Answer : Option (D) : GPS only

Explanation : Each FMS computes the aircraft position and the position accuracy. The FMS computed position is an optimum combination of the inertial position and the GPS or radio position, depending on which equipment provides the most accurate data. This results in four navigation modes: Inertial (IRS) – GPS, Inertial (IRS) – DME/DME, Inertial (IRS) – VOR/DME, Inertial (IRS) only. The only GPS is not used as the position information is within a radius where the aircraft is flying.