Chapter 22 – Auto Flight
Auto Pilot
An autopilot is a device used to guide an aircraft without direct
assistance from the pilot.
Autopilot software, which is integrated with the navigation systems,
is capable of providing control of the aircraft throughout each phase
of flight.
If an autothrottle/autothrust system is installed, the appropriate
thrust may be automatically set during take-off, and is then adjusted
automatically as the climb progresses, while the aircraft climbs at the
appropriate speed for its mass and ambient conditions.
• An option midway between fully automated flight and manual flying
is Control Wheel Steering (CWS).
• In CWS mode, the pilot controls the autopilot through inputs on the
yoke or the stick.
• These inputs are translated to a specific heading and attitude, which
the autopilot will then hold until instructed to do otherwise.
Chapter 23 - Communication
The aircraft communication system is used for speech (voice)
communications and also for data communications.
Aircraft communications systems comprise the following:
Radio Communication - HF System for long-distance voice
communications./VHF System for short-range voice communications.
Radio Management Panels
SELCAL System – For selective calling using HF and VHF
SATCOM System – For satellite communication
ACARS – For datalink communication
Interphone Communication - Flight Interphone System for internal
cockpit communication and also with ground mechanics/Cabin
Interphone System for cabin crew or cabin crew and pilots
communications./Service Interphone System(On ground only) for
maintenance personnel only.
Ground Crew Call System – To tell ground crew or flight crew there is
a call.
Passenger Address System – For passenger announcement from
cockpit and cabin crew station.
Audio Management System
Chapter 24 - Electrical
Engine Driven Generator
Main electricity generation is done by engine driven generators.
Since engines rpm are varying depend on the trust requirement,
there is an another device called as Constant Speed Drive(CSD)
connected between the engine and the generator, which help to
rotate generator in constant speed irrespective of different engine
speed.
This CSD helps to regulate voltage and current in the generator.
Batteries
Batteries are used as emergency electricity generation system.
In an electrical emergency (means, if all the generators are
failed),batteries act as backup electricity source and can give around
half an hour of electricity before they fully drain.
Batteries are connected to essential bus bars and, will power most
critical systems in an emergency.
Nickel Cadmium and Lead Acid are mostly used type of batteries in
aircraft.
Emergency Generator/RAT system
In an electrical emergency, apart from the batteries, most of the
aircraft are benefitted by emergency generator as well.
It is a generator which rotates by means of ram air instead of the
engine.
Ram Air Turbine(RAT) is a device which in normal condition keep
retracted inside aircraft. But when required, it can be extended
manually by pilot or, will be extended automatically so, turbine will be
rotated by outside ram air.
That turbine will eventually rotates an emergency generator mostly
by pressurizing relevant hydraulic system.
In most modern aircraft, emergency generator is rotated by hydraulic
assisted motor.
Chapter 31 – Indicating And Recording System
Flight Instruments
Flight instruments are the instruments in the cockpit of an aircraft
that provide the pilot with data about the flight situation of that
aircraft, such as altitude, airspeed, vertical speed, heading and much
more other crucial information in flight.
A – PFD /B – ND / C,D – ECAM OR EICAS / E – Standby ADI / F – Clock / G – MCDU OR CDU
CVR/DFDR
A flight recorder is an electronic recording device placed in an aircraft
for the purpose of facilitating the investigation of aviation accidents
and incidents.
There are two types of flight recording devices: the flight data
recorder (FDR) preserves the recent history of the flight through the
recording of dozens of parameters collected several times per second;
the cockpit voice recorder (CVR) preserves the recent history of the
sounds in the cockpit, including the conversation of the pilots.
Chapter 34 - Navigation
VOR
VHF Omnidirectional Radio Range.
It uses frequencies in the very high frequency (VHF) band from
108.00 to 117.95 MHz.
VORs broadcast a VHF radio composite signal including the station's
Morse Code identifier (and sometimes a voice identifier).
These data allow the airborne receiving equipment to derive the
magnetic bearing from the station to the aircraft.
Distance Measuring Equipment (DME)
Distance Measuring Equipment (DME) is defined as a navigation
beacon, usually coupled with a VOR beacon, to enable aircraft to
measure their position relative to that beacon.
Aircraft send out a signal which is sent back after a fixed delay by the
DME ground equipment.
The VOR allows the receiver to measure its bearing to or from the
beacon, while the DME provides the slant distance between the
receiver and the station. Together, the two measurements allow the
receiver to compute a position fix.
TCAS
Stands for Traffic Collision Avoiding System.
 It monitors the airspace around an aircraft for other aircraft
equipped with a corresponding active transponder, independent of
air traffic control, and warns pilots of the presence of other
transponder-equipped aircraft which may present a threat of mid air
collision.
Each TCAS-equipped aircraft interrogates all other aircraft in a
determined range about their position (via the 1030 MHz radio
frequency), and all other aircraft reply to other interrogations (via
1090 MHz).
This interrogation-and-response cycle may occur several times per
second.
ILS
Stands for Instrument Landing System.
It is a precision runway approach aid based on two radio beams
which together provide pilots with both vertical and horizontal
guidance during an approach to land.
Its vertical guidance is given by glide slope antenna while lateral
guidance is given by localizer antenna.
Pilots can see these guidance on there attitude director indicator
and, should follow them in order to perform instrument guided
landing.
Signals are emitted by ground based antennas and receives by
aircraft on boards antenna system.
Way Points.
A waypoint is a specified geographical location used to define an area
navigation route or the flight path of an aircraft employing area
navigation.
Waypoints are identified as either:
Fly-by waypoint. A waypoint which requires turn anticipation to allow
tangential interception of the next segment of a route or procedure,
or
Flyover waypoint. A waypoint at which a turn is initiated in order to
join the next segment of a route or procedure.
Inertial Navigation System
It is a self-contained navigation technique which can calculate
position, orientation, and velocity to deliver critical navigation
information.
It relies on accelerometers and gyroscopes to detect acceleration and
velocity respectively along 3 perpendicular axes.
An approximate 2 or 3 dimensional position can be constantly
determined in relation to a known starting point, velocity and
orientation.
Airdata System
This system can computes altitude, vertical speed, air speed, and
Mach number from pressure and temperature inputs.
Can determine the calibrated airspeed, Mach number, altitude, and
altitude trend data from an aircraft's pitot-static system
A pitot-static system generally consists of a pitot tube, a static port,
and the pitot-static instruments.
The airspeed indicator is connected to both the pitot and static
pressure sources.
The difference between the pitot pressure and the static pressure is
called dynamic pressure. The greater the dynamic pressure, the
higher the airspeed reported.
The pressure altimeter, also known as the barometric altimeter, is
used to determine changes in air pressure that occur as the aircraft's
altitude changes.
Indicated airspeed ("IAS") - What is read on an airspeed gauge
connected to a Pitot-static system.
Calibrated airspeed ("CAS") - Indicated airspeed adjusted for pitot
system position and installation error.
True airspeed ("TAS") - Equivalent airspeed adjusted for air density,
and is the speed of the aircraft through the air in which it is flying.
Flight Management System (FMS)
FMS is a specialized computer system that automates a wide variety
of in-flight tasks, reducing the workload on the flight crew to the
point that modern civilian aircraft no longer carry flight engineers or
navigators.
A primary function is in-flight management of the flight plan.
 The system is constantly updated with aircraft position by reference
to available navigation aids.
The most appropriate aids are automatically selected during
information update.
 It may include Inertial Reference System (IRS) and Global Positioning
System (GPS) (GPS) inputs in addition to receivers for ground based
aids.
It predominantly uses navigation data base for its functions.
Navigation Database - This database provides the primary navigation
function with location, frequency, elevation and class information of
various ground based radio navigation systems.
Performance database - This database contains aircraft and engine
model data consisting of thrust, drag, fuel flow, speed/altitude
envelope and variety of optimized speed schedules that are unique to
the aircraft.
Chapter 45 – On board Maintenance System
Central Maintenance System
A central maintenance computer collects and stores maintenance
data for aircraft systems.
Primary functions include fault processing, testing, fault history and
reporting.
The CMC monitors aircraft systems for faults, processes fault
information and supplies maintenance messages.
The CMC stores and manages warnings generated by the built in test
equipment (BITE) function integrated within aircraft computers.
• The BITE systems provide diagnostic information in the case of system
malfunctions, and related maintenance features.
• BITE test function in CMS is only available on ground.
• There are two Central Maintenance Computers. In auto mode, CMC 1
will be active while CMC 2 in standby mode.
• If in case 1 is failed,2 automatically takes control.
• If one of them selected off manually, other one will take control as
well.
Aircraft Condition And Mentoring System (ACMS)
An Aircraft Condition Monitoring System (ACMS) is a predictive
maintenance tool consisting of a high capacity flight data acquisition
unit and the associated sensors that sample, monitor, and record,
information and flight parameters from significant aircraft systems
and components.
Depending upon the piece of machinery or type of component
concerned, there are a number of different parameters that can be
measured or monitored.
Vibration monitors, Temperature monitors, Pressure monitors,
Electrical current measurement and analysis and Speed ​Measurement
are few types of monitoring this system accomplished.
The End