E368 Autoflight Systems

E368 Autoflight Systems (4 Modular Credits)
This document addresses the content-related abilities, with reference to the module, as applied to the
aerospace MRO environment. Abilities of thinking, learning, problem solving, and teamwork, communication,
debating and defending are addressed by the system wide curricular practices at Republic Polytechnic.
Module Synopsis
This module provides a conceptual framework and imparts a general knowledge of the theoretical and
practical aspects Autoflight systems. The contents in the module will fulfill the Autoflight systems (ATA 22)
knowledge required in SAR-66 Module 13. The requirement for this module is Cat B2. The module enables
the students to understand the technical fundamentals of the various Autoflight systems, and apply the
knowledge in a practical manner. The students should also be able to understand technical drawings and
schematics of aircraft Autoflight systems, and give a general description of their operations.
Module Learning Outcomes
Throughout the course, the students will learn how to:
Aircraft stability and control
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Differentiate between aircraft stability and controllability
Describe the factors contributing to aircraft stability and controllability
Describe the conditions for longitudinal static stability
Discuss the various means of enhancing static stability in aircraft.
Describe the various dynamic motions in an aircraft.
Differentiate between power-assisted and power-operated flight controls.
Servomechanisms
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Explain the construction and operation of servomotors and servo-actuators to convert command signals
to powered control
Fly-by wire (FBW) Control Systems
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Explain the operation of the various components in a Fly-by-wire system
Automatic Flight Control systems (AFCS)
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Explain the architecture and functions of the different elements in a typical AFCS block diagram.
Analyze the requirements of a control system and formulate the concept by means of a block diagram.
Describe the response of an un-damped servomechanism system and its effect on flight dynamics.
Response of servomechanism
Strictly Confidential. For Articulation Purpose Only.
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Recognize the different degrees of damping as shown in a response vs. time graph. Examine the effects
of an under-damped and over-damped system on an aircraft.
Differentiate between rate-damping and autopilot control systems (i.e. stability vs. control requirements)
Stability augmentation
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Explain the concept of a Stability Augmentation System (SAS).
Analyze the response of a direct-control yaw damper vs. a phase advance system.
Interpret the indications of a trim indicator.
Define the basic mode of autopilot operations.
Explain the schematic of a simple attitude hold autopilot
Explain the operation of control wheel steering (CWS) or manual mode.
Devise a block diagram and operational arrangement of a heading hold autopilot system.
Outer loop control
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Identify the higher modes of AFCS
Explain the operation of the attitude select, heading select, vertical speed modes of operations.
Devise a block diagram and operational arrangement of an altitude select autopilot system.
Explain the rationale of integrating the autopilot with the navigational aids.
List the different autopilot navigational modes and the related navigational inputs.
Explain the process flow of an aircraft transiting from heading mode, VOR to ILS approach mode.
Describe the flying sequence of a landing approach until the rollout phase.
Explain the dynamics of the “flare” maneuvers during landing
Describe the process flow of auto land and aircraft go-around operations
Helicopter /AFCS combinations
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Discriminate the autopilot requirements of a helicopter as compared to a fixed wing aircraft
Describe the maneuvers performed by the helicopter operational modes
Explain the schematic of a typical helicopter AFCS
Identify the various controls and selections available in a typical autopilot control panel.
Flight Director (FD) Systems
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Identify the various indications and annunciations on a typical Attitude Director Indicator (ADI)
Interpret the “commands” provided by the ADI and the correct pilot actions to take
Explain the various operating modes of an FD system and its selection on the mode selector panel.
Analyze the FD engage logic circuit.
Strictly Confidential. For Articulation Purpose Only.
Module Coverage
Allocated time per day
(One day-One problem PBL pedagogy)
Module Coverage
Discussions in
study cluster
P01 – Stability and Control
• Differentiate between aircraft stability and
controllability
• Explain static and dynamic stability using
examples.
• Appreciate how excessive stability can
affect controllability and vice versa.
• Describe the factors contributing to an
aircraft’s (1) stability and (2) controllability
• Identify the conditions that must be satisfied
for an aircraft to be in equilibrium
• Describe aircraft motion relating to positive,
negative and neutral stability
P02 – Is this Aircraft Stable?
• Define aerodynamic center and appreciate
how it relates to an aircraft moment about
its centre of gravity.
• Describe the conditions for longitudinal
static stability
• Illustrate positive longitudinal stability using
a graph.
• Calculate pitching moments arising from the
different components such as wing-plane
and tail-plane.
• Explain the effect of canards, horizontal
stab and wash-out on the longitudinal static
stability of an aircraft.
• Explain the effects of extreme static
stability.
P03 – Aircraft Oscillations
• Appreciate the significance of good
dynamic stability in an aircraft.
• Describe the various dynamic motions in an
aircraft: phugoid, short-period longitudinal
motions, wing rock, roll control reversals,
spiral and dutch roll.
• Utilise the damping ratio and natural
Resource gathering and
team work
Laboratory
4
2
0
4
2
0
4
2
0
Strictly Confidential. For Articulation Purpose Only.
frequency to determine the degree of
dynamic stability.
• Compare and contrast the phugoid vs
short-period modes, and explain their
effects on flying.
• Explain factors that affect the phugoid and
short period modes, as well as the design
trade-offs.
• Analyse the trade-offs between design for
good spiral and dutch roll characteristics.
• Utilise the Cooper Harper Scale to
determine flying quality.
P04 – Flying Wing
• Explain the operation of a mechanical flight
control system and analyse its limitations in
flight control.
• Appreciate the need for powered flight
controls.
• Differentiate between power-assisted and
power-operated flight controls.
• Explain the principle of the various types of
servo-actuators: pneumatic, electrical,
hydraulics.
• Explain the operation of the various
components in a Fly-by-wire system
P05 – Flying Auto
• Explain the main role of an automatic flight
control system (AFCS) and the significance
in different aircraft types.
• Explain the architecture and functions of the
different elements in a typical AFCS block
diagram.
• Distinguish between outer and inner-loop
control.
• Identify key components in an AFCS
according to the 3 main elements: sensors,
computation, output.
• Describe the function of the following AFCS
interfaces: FCU / MCP, FMS and flight
director.
• Appreciate the need for multiple
redundancies in autoflight system
architecture
• Compare and contrast the various levels of
redundancies: duplex, triplex and
quadruplex.
• Differentiate between fail-passive and
fail-operational AFCS.
3
1
2
4
2
0
Strictly Confidential. For Articulation Purpose Only.
P06 – Servo Behavior
• Differentiate between a closed-loop and
open-loop control system.
• Analyse the operation of aircraft
servomechanisms as a closed loop control
system.
• Appreciate the following terms: feedback,
null, deadband, transducer, damping.
• Utilise a block diagram to study the process
flow of a typical aircraft servo-actuator.
• Differentiate between position control vs
speed control servomechanisms, and its
applications in aircraft.
• Describe the response of an un-damped
servomechanism system and its effect on
flight dynamics.
• Calculate closed loop transfer function and
use it to determine the response of a
servomechanism.
• Explain how the PID controller can be used
to achieve the desired response of a
servomechanism.
P07 – Make it Stable
• Appreciate the need to model aircraft
dynamics to achieve the desired stability
characteristics.
• Differentiate between rate-damping and
autopilot control systems (i.e. stability vs
control requirements)
• Utilize SPPO example to calculate the
damping ratio and natural frequency.
• Describe the operation and components in
a simple rate damping system
• Describe the trade-offs of a simple rate
damper.
• Describe the implementation of a Stability
augmentation system (SAS).
• Explain the concept of Stability Control and
Augmentation System (SCAS).
P08 – What a Damper
• Appreciate the flight dynamics of dutch roll
and the need to damp the oscillations.
• Analyse the response of a direct-control
yaw damper vs a phase advance system.
• Explain the block diagram of a yaw damper
system
• Describe the 3 methods of controlling the
rudders of a large aircraft.
4
2
0
3
2
1
4
2
0
Strictly Confidential. For Articulation Purpose Only.
• Explain the rationale and operation of the
torque limiter.
• Describe why rudder action is required for
turn coordination and how this can be
implemented in the yaw damper system.
• Describe the operation of the yaw channel
in a large aircraft and how the yaw damper
fits in.
P09 – Out of Trim
• Appreciate the significance of trimming in
an aircraft during flight.
• Explain the use of the different trim devices:
trim tabs, balance panel and variable
incidence horizontal stab.
• Analyze the advantages of using a variable
horizontal stab.
• Explain the operation of a pitch trim system
of a large aircraft.
• Identify the inputs and processing
requirements for auto trim contol.
• Explain operation of auto trim in the pitch
control channel of a flight control system.
• Describe the implementation of trimmable
horizontal stab (THS) in Airbus.
P10 – Keep it there
• Define the basic mode of autopilot
operations.
• Explain the use of different command signal
processing in autopilot systems:
Differentiating / integrating, demodulating,
amplifying, limiting, gain programming,
feedback application.
• Explain the schematic of a simple attitude
hold autopilot
• Interpret a circuit diagram to determine
specific interlocks for successful
engagement of autopilot system
• Program and test altitude hold using
algorithm using labview
• Operate the control panel to engage the
altitude hold mode
• Explain the operation of control wheel
steering (CWS) or manual mode.
P11 – Exact Height
• Differentiate between an roll attitude and
heading hold autopilot
• Devise a block diagram and operational
4
2
0
4
2
0
3
2
1
Strictly Confidential. For Articulation Purpose Only.
arrangement of a heading hold autopilot
system.
• Explain the sources of the input to the
heading hold autopilot
• Interpret the roll control channel schematic
of a large aircraft, and relate to the
operation of the different roll modes.
• Program and test altitude hold algorithm
using labview
• Operate the control panel to engage the
heading hold mode
P12 – Manoeuvre on its own
• Identify the higher modes of AFCS
• Explain the operation of the altitude select,
heading select, vertical speed modes of
operations.
• Devise a block diagram and operational
arrangement of a altitude select autopilot
system.
• Explain the sources of the input to the
altitude select autopilot
• Interpret the pitch control channel
schematic of a large aircraft, and relate to
the operation of the different pitch modes.
• Program higher AFCS modes using labview
• Operate the control panel to engage the
required modes
P13 – Self Navigation
• Explain the rationale of integrating the
autopilot with the navigational aids.
• List the different autopilot navigational
modes and explain their interface with the
related navigational aids.
• Describe the submodes of each of the
navigational modes.
• Explain the process flow of an aircraft
transiting from heading mode, VOR to ILS
approach mode.
• Program the navigational mode of autopilot
using labview
• Operate the control panel to engage the
required modes
P14 – Blinding Landing
• Define All Weather Operations (AWO)
• Explain the terms : Decision Height. Alert
Height. MDA, RVR, Missed approach.
• Describe the flying sequence of a landing
approach until the roll-out phase.
3
1.5
1.5
3
1.5
1.5
2
1
3
Strictly Confidential. For Articulation Purpose Only.
• Explain the operation of an aircraft
auto-throttle system.
• Explain the dynamics of the “flare”
manoeuvre during landing
• Describe the process flow of autoland and
aircraft go-around operations
P15 – Chop or Drop
• Discriminate the autopilot requirements of a
helicopter as compared to a fixed wing
aircraft
• Explain the use of stability augmentation
systems in helicopters.
• Differentiate between the basic and
operational AFCS modes
• Describe the manoeuvres performed by the
operational modes
• Explain the schematic of a typical helicopter
AFCS
• Identify the various controls and selections
available in a typical autopilot control panel.
Total = 15 Problems
= 90 hrs
4
2
0
53
27
10
Strictly Confidential. For Articulation Purpose Only.

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