ELEC4504/4906G AVIONICS SYSTEMS ENGINEERING

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ELEC4504/4906GAVIONICS SYSTEMS ENGINEERING
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INTRODUCTION

• OBJECTIVES
• SOME HISTORY
• FACTORS AFFECTING AVIONICS DEVELOPMENT

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COURSE OBJECTIVES

• To provide the aeronautical engineering student
  with knowledge of
• The basic principles behind the avionics systems
  used in civil aircraft
• The factors which should be taken into account
  when installing avionics in aircraft and
• How the avionics systems are used in the
  operation of a commercial aircraft

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COURSE OUTLINE

• Organizational Framework
• Air Traffic Control
• CNS Communications/ Navigation /Surveillance
• The Electromagnetic Spectrum
• Navigation
• Precision Approach Systems
• Communications Systems
• Radar and Surveillance Systems

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COURSE OUTLINE(CONTINUED)

1. Control Systems
2. Flight Management Systems
3. Display Systems
4. Electrical Systems
5. System Design
6. System Testing
7. Future Developments

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Factors Affecting Avionics Development
Sometimes it appears to take a long time to
introduce new systems into service. There are
several reasons for this

1. Cost
2. Number of systems in service
3. Benefits
4. Reliability

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ORGANIZATIONAL FRAMEWORK

1. ICAO (International Civil Aviation Organization)
2. National Civil Aviation Organizations (FAA, CAA,
   Transport Canada).
3. RTCA
4. SAE
5. ARINC
6. EUROCAE

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ORGANIZATIONAL FRAMEWORK

• ICAO (International Civil Aviation Organization)
• Part of the United Nations
• Headquarters in Montreal
• Since civil aviation is an international
  activity, it is beneficial for all nations to use
  the same standards for most aspects of their
  aviation operations.

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ICAO

• ICAO provides this service through documents
  called SARPS (standards and recommended
  practices)
• Examples of activities covered by SARPS are
• Aircrew licensing
• Weather reports
• Flight plan forms
• Registration Markings
• Navigation Systems

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ICAO

• ICAO (Continued)
• For example the SARPs on Navigation defines the
  characteristics of the Instrument Landing System
  (ILS) and includes
• Signal strength
• Signal format
• Accuracy
• Coverage (distances at which usable signal can be
  detected)

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ICAO

• ICAO (Continued)
• Note that all of these documents are
  recommendations only. Each country (or state)
  makes its own laws and rules
• It is advantageous, however, for a country to
  follow these SARPS since non-standard practices
  discourage other countries from operating into
  such states.

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ORGANIZATIONAL FRAMEWORK

• 2. RTCA (Requirements and Technical Concepts for
  Aviation)
• Formerly known as the Radio Technical Committee
  for Aeronautics
• and Radio Technical Commission for Aeronautics
• An example of the FAAs practice of contracting
  out much of its technical work
• To understand the role of RTCA it is necessary to
  understand the FAAs TSO (Technical Standard
  Order)

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RTCA

• A given TSO is a minimum performance standard for
  a given piece of aircraft equipment (not
  restricted to avionics equipment)
• A TSO authorization is the FAAs recognition that
  a given design meets the TSO and also authorizes
  the manufacturer to produce it.
• While the TSO authorization is not an approval to
  install the equipment it gives the equipment a
  very great advantage in obtaining certification
  for its installation
• One of the first questions you are asked, if you
  want to install some equipment in an aircraft is
  is it TSOd?
• Thus a TSO is very important

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RTCA

• Q Where do TSOs come from?
• A RTCA
• When the FAA determines the need for a new piece
  of equipment e.g. a GPS receiver, it contacts the
  RTCA.
• RTCA then establishes a committee (called a
  special committee) and invites anyone with any
  interest in the subject to join the committee.
  (airlines, equipment manufacturers, FAA
  officials, aircraft associations and
  international representatives)
• GPS committee is SC-159
• The committee produces a document called a MOPS
  (minimum operational performance standard) This
  is given a number preceded by DO
• e.g. the MOPS for the GPS receiver is DO-208

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RTCA

• The RTCA MOPS is then submitted to the FAA which
  uses it as the basis for the TSO
• The GPS receiver TSO is TSO-C129a
• Thus the RTCA is a very powerful organization in
  the development of aircraft equipment (not just
  avionics)

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ORGANIZATIONAL FRAMEWORK

• ARINC (Aeronautical Radio Inc)
• Started in the 1930s by a group of airlines to
  provide communications between their aircraft and
  their bases.
• It still provides this service through the ATN
  (Aeronautical Telecommunications Network) and
  ACARS (Aircraft Communications and Addressing
  System)
• For avionics, however it is important for
  standardizing aircraft electronics boxes, trays
  and connectors.
• Later it developed standards for aircraft digital
  data busses.

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ARINC

• ARINC (Aeronautical Radio Inc)
• Started in the 1930s by a group of airlines to
  provide communications between their aircraft and
  their bases.
• It still provides this service through the ATN
  (Aeronautical Telecommunications Network) and
  ACARS (Aircraft Communications and Addressing
  System)
• For avionics, however it is important for
  standardizing aircraft electronics boxes, trays
  and connectors.

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ARINC

• ARINC (Aeronautical Radio Inc)
• Started in the 1930s by a group of airlines to
  provide communications between their aircraft and
  their bases.
• It still provides this service through the ATN
  (Aeronautical Telecommunications Network) and
  ACARS (Aircraft Communications and Addressing
  System)
• For avionics, however it is important for
  standardizing aircraft electronics boxes, trays
  and connectors.

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ARINC

• Electronic Equipment in aircraft has to be
• Firmly attached to the aircraft structure (by
  means of racks)
• Wired in to the aircraft systems
• Power
• Signals
• Controls

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ARINC

• Early Electronic Equipment was not standardized
  and hence the mounting systems and connectors
  were different not only for each piece of
  equipment but for the same equipment from
  different manufacturers
• Thus upgrading equipment was expensive and time
  consuming
• ARINC devised a set of standard black box sizes
  and corresponding mounting systems as well as
  connector designs.

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ARINC

• With standardized racks, boxes, trays and
  connectors, airlines could choose among various
  manufacturers of a particular item (e.g.
  Communications Transceiver) knowing that all they
  had to do was pull out the old set and plug in
  the new one.

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ARINC

• The original standard was called ARINC 404.
• Or ATR (Air Transport Racking)
• Black box sizes were 1ATR, 3/4ATR, ½ ATR, ¼ ATR
  etc.
• A 1ATR box was about 10 wide, 8high and 22
  deep
• The latest racking standard is ARINC 600 series.

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ARINC

• With the advent of digital communications in
  aircraft, ARINC developed popular digital data
  bus communications standards, primarily ARINC 429
  and ARINC 629

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SAE

• SAE (originally Society of Automotive Engineers,
  now SAE International)
• Another organization which develops standards.
• For avionics the primary publications are ARPs
  (Aerospace Recommended Practices)
• ARP5672 - Aircraft Precipitation Static
  Certification
• AS 5672A - ARC Fault Circuit Breaker (AFCB),
  Aircraft, Trip-Free Single Phase and Three Phase
  115 VAC, 400 Hz - Constant Frequency

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EUROCAE

• EUROCAE is essentially the European version of
  RTCA
• The two organizations work closely together and
  publish joint standards.

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AIR TRAFFIC CONTROL (ATC)AND ITS RELATIONSHIP TO
AVIONICS SYSTEMS
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OBJECTIVES OF ATC

• Maintain separation of aircraft
• Expedite the flow of Air Traffic
• NOT responsible for the separation of aircraft
  from the ground (except when in radar contact

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RESPONSIBILITES OF THE PILOT (GENERAL)

• Maintain aircraft ATTITUDE
• Navigate the aircraft from departure to
  destination
• Avoid collision with other aircraft
• How these are accomplished depends on the weather
• (specifically ceiling and visibility)

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VISUAL METEOROLOGICAL CONDITIONS (VMC)

• Generally 3 miles visibility and 1000 Ft. ceiling
• Visual Flight Rules (VFR) apply
• Attitude maintained by visual reference to the
  horizon
• Navigation by reference to the ground (or
  electronic aids if pilot is able to and aircraft
  is so equipped
• Separation from other aircraft by visual contact
  (see and be seen) Note ATC will assist but is
  not responsible.
• Aircraft not allowed to enter cloud

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VFR ON TOP

• With extra training in radionavigation, pilots
  can fly in clear air above cloud
• Note Attitude is still with reference to the
  visible horizon
• Climb and descent must not require entry into
  cloud

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INSTRUMENT METEOROLOGICAL CONDITIONS (IMC)

• IMC exist whenever VMC do not
• Obviously the rules pertaining to IMC are IFR
  (Instrument Flight Rules)
• IFR apply in IMC and also to all flight above
  18000 Ft in Canada and the USA (other altitudes
  are specified in other countries)

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INSTRUMENT FLIGHT RULES

• Separation from other aircraft is responsibility
  of ATC
• ATC issues clearances which are specific
  routes/altitudes which must be followed.
• Attitude (pitch, bank and heading) is maintained
  with reference to instruments.
• Simplest artificial horizon and compass
• More complex inertial navigation system
• Navigation is done using electronic navigation
  aids
• Two way communication is required between pilot
  and controller
• ATC must know where aircraft is
• ATC radar requires a transponder on the aircraft

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INSTRUMENT FLIGHT RULES

• On-board Collision Avoidance Systems supplement
  ATC
• Terrain Avoidance Systems provide protection from
  CFIT (Controlled Flight Into Terrain) when
  aircraft is out of radar coverage

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Typical IFR Flight Procedure

• Pilot plans route (including altitudes) from
  departure point to destination
• Pilot files flight plan
• ATC decides if flight plan can be accepted as is
  or if it needs to be amended
• Prior to starting engines, pilot requests ATC
  clearance.
• ATC gives clearance (may be just flight planned
  route)
• Pilot contacts ground control for taxi clearance

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Typical IFR Flight Procedure

• Aircraft taxis to runway
• Takeoff clearance is obtained from Tower
• After takeoff, pilot contacts Departure Control
  who gives vectors or a series of headings and
  altitudes to guide aircraft to the start of the
  route to which it has been cleared
• Near destination, Arrival Control provides
  vectors to the landing approach.
• Tower gives clearance to land
• Ground Control gives clearance to taxi to arrival
  gate