ACARS,TCAS,IRS,FMS.

1. Typical electronic/ Digital Aircraft System 1

3. ECAM - Electronic Centralized Aircraft Monitoring

4. EFIS - Electronic Flight Instrument System

5. EICAS - Engine Indication and Crew Alerting System

6. FBW - Fly by Wire

7. FMS - Flight Management System

8. GPS - Global Positioning System

9. IRS - Inertial Reference System

10. TCAS - Traffic Alert Collision Avoidance System2

11. ACARS - ARINC Communication and Addressing and Reporting System The aircraft communications addressing and reporting system (ACARS) is a data link communication system. It lets you transmit messages and reports between an airplane and an airline ground base. 3

13. Out, off, on, in (OOOI) times

14. Engine performance

15. Flight status

16. Maintenance items. 4

18. Control display unit (CDU)

19. ACARS program switch modules

20. Management unit (MU).

21. One can use the control display unit (CDU) or the IDU to control the operation of the ACARS and the CDU to show ACARS messages. The ACARS program switch modules contain dual inline package (DIP) switches. These switches identify the airplane.

22. The ACARS MU receives the ground-to-air digital messages (uplink). It controls the transmission of the air-to-ground digital messages (downlink). 5

24. Printer - to print ACARS reports and messages.

26. SELCAL control panel - to signal the flight crew of incoming ACARS message that require flight crew attention.

27. Proximity switch electronics unit - to send discrete signals for out, off, on and in (OOOI) events. 6

29. Flight data acquisition unit

30. Data loader control panel7

31. ACARS - ARINC Communication and Addressing and Reporting System 8 Figure : ACARS Management Unit and Interface

32. ACARS - ARINC Communication and Addressing and Reporting System Management Unit The ACARS management unit (MU) gets uplink data from the VHF transceiver. It controls downlink data transmission from the VHF transceiver. The MU processes only uplink messages that have the airplane registration code. This same code is sent on all downlink messages to identify the airplane. ACARS Programming The ACARS program switch modules contain dual inline package (DIP) switches. These set the airplane identification and registration codes. 9

33. ACARS - ARINC Communication and Addressing and Reporting System Operation The flight management computer system control display unit (CDU) or the interactive display unit (IDU) gives one an interface with the ACARS system. They lets one enter, send, and review downlink/uplink data. The CDU shows ACARS messages in the scratch pad, the IDU shows ACARS messages on the display. IDU Features The IDU has a MENU key that selects the menu. From the menu page, you can select ACARS or the flight data acquisition unit aircraft condition monitoring system (ACMS). Software Loading 10

34. EFIS – Electronic Flight Instrument System General Description: A complete EFIS installation in an aircraft is made up of left (Captain) and right (co-pilot) systems, each system in turn being composed of two display units (an attitude director indicator (ADI) and a horizontal situation indicator (HSI), a control panel, a symbol generator and a remote light sensor. A third (centre) symbol generator is also incorporated so that drive signals from this generator may be switched to either the left or right display units in the event of failure of their corresponding generators. 11

35. EFIS – Electronic Flight Instrument System 12

36. EFIS – Electronic Flight Instrument System 13 Figure : Simplified block diagram of display unit

38. The power supply units provide the requisite levels of a.c. and d.c. power necessary for overall operation of the display units.

39. The video/monitor card contains a video control microprocessor, video amplifiers and monitoring logic for the display unit. The main tasks of the processor and associated EPROM and RAM, are to calculate gain factors for the three video amplifiers (red, blue and green), and perform input sensor and display unit monitor functions. 14

41. The function of the convergence card is to take X and Y deflection signals and to develop drive signals for the three radial convergence (red. blue and green) coils and the one lateral convergence (blue) coil of the CRT.

42. Signals for the X and Y beam deflections for stroke and raster writing are provided by the deflection amplifier card. The amplifiers for both beams each consist of a two-stage preamplifier, and a power amplifier. The amplifiers use two supply inputs, 15 V d.c. and 28 V d.c. the former is used for effecting most of the stroke writing, while the latter is used for repositioning and raster writing. 15

43. EFIS – Electronic Flight Instrument System Symbol Generators These provide the analog discrete and digital signal interfaces to the aircraft systems display units and control panel and they perform symbol generation system monitoring, power control and the main control functions of the EFIS. Remote Light Sensor This is a photodiode device which responds to flight deck ambient light conditions and automatically adjusts the brightness of the electronic displays to a compatible level. 16

44. EFIS – Electronic Flight Instrument System 17

45. EFIS – Electronic Flight Instrument System 18

47. The system provides the flight crew with information on primary engine parameters (full-time) and with secondary engine parameters and warning / caution / advisory alert messages (as required).

48. Display units The units are mounted one above the other, the upper unit displaying the primary engine parameters (EPR, N1 and EGT) and warning and caution messages, while the lower unit displays secondary engine parameters (N2, N3, fuel flow, oil quantity, pressure and temperature, and engine vibration), status of non-engine systems, aircraft configuration and maintenance data. 19

50. Warning, caution and advisory messages are displayed in red and yellow on the left-hand side of the upper display unit screen as conditions dictate. Abnormal secondary engine parameters are automatically displayed on the lower display unit.

51. In each case the highest value attained is displayed in white under the actual readout, and the accumulated exceedance time is stored in a non-volatile memory of the computer for subsequent readout during maintenance mode checks.20

52. EICAS – Engine Indicating and Crew Alerting System 21 Figure : EICAS Maintenance Panel

53. EICAS – Engine Indicating and Crew Alerting System 22 Schematic functional diagram -EICAS

55. A second switch (STATUS) is provided on the control panel and when pressed it switches the lower display into a mode that displays the status of several systems (e.g. flight control surface positions) and also up to 16 status messages requiring flight crew awareness prior to take-off and in flight. 23

57. There are four display modes, three of which are automatically selected and referred to as flight phase-related, advisory (mode and status) and failure-related modes. The fourth mode is manual and permits the selection of diagrams related to any one of twelve of the aircraft's systems for routine checking. The selections are made by means of illuminated push-button switches on the ECAM control panel. 24

58. ECAM – Electronic Centralized Aircraft Monitoring 25

60. The failure-related mode takes precedence over the two other automatic modes and the manual mode.

61. STATUS messages, which are also displayed on the left-hand display unit, provide the flight crew with an operational summary of the aircraft's condition, possible downgrading of auto land capability, and as far as possible, and indications of the aircraft status following all failures except those that do not affect the flight.26

62. ECAM – Electronic Centralized Aircraft Monitoring 27 Figure ECAM upper display

63. ECAM – Electronic Centralized Aircraft Monitoring 28 Figure ECAM lower display

64. ECAM – Electronic Centralized Aircraft Monitoring 29

65. ECAM – Electronic Centralized Aircraft Monitoring 30 Figure : ECAM Control Panel

67. Two Control and Display Units (CDU)

68. Thrust Mode Annunciator (TMA)

69. Stored within the FMC is:Navigation Data Base - used to define route selection and contains airports, procedures, waypoints, navaidsetc. This portion of the internal data is inputted and updated by a portable data base loader and connector in the flight deck area. The CDU provides the interface between the crew and the FMC, and data exchange is provided by ARINC 429 busses. 31

70. Flight Management System 32 Figure : Flight Management System

72. Any subsequent changes in navigation aids and procedures, and route structure changes, are also incorporated in the data base by means of the data loader, in accordance with a specified time schedule, e.g., a 28-day cycle. 33

73. Flight Management System 34

74. Flight Management System 35

78. In the event of failure of one computer, each pilot has the means whereby he can select his own CDU into the other system.38

79. Flight Management System 39 Figure : FMCS System Configuration

83. The cable-controlled system comes with a weight penalty due to the long cable runs, pulleys, brackets, and supports needed. The system requires periodic maintenance, such as lubrication and adjustments due to cable stretch over time.

84. In addition, systems such as the yaw damper that provide enhanced control of the flight control surfaces require dedicated actuation, wiring, and electronic controllers. This adds to the overall system weight and increases the number of components in the system41

86. The main advantages of fly-by-wire are:

87. Saving in weight.

88. Requires less maintenance.

89. More responsive.

90. Increased fuel economy.

91. Built in protection systems.

92. Integration of several federated systems into a single system.

93. Greater flexibility for including new functionality or changes after initial design and production.

94. Ease of maintenance. 42

98. Integration of functions such as the yaw damper into the basic surface control.

99. Improved system reliability and maintainability. 45

100. Fly By Wire (FBW) 46 Figure: The Primary Flight Control System on a typical aircraft is comprised of the outboard ailerons, flaps, elevator, rudder, horizontal stabilizer, and the spoiler/speed brakes.

102. The secondary systems comprise leading edge slats and trailing edge flaps for low speed flight handling, airbrakes/load alleviation spoilers for deceleration/load alleviation at all flight speeds and lift dumpers for deceleration after landing.

103. An aircraft flight controls are hydraulically actuated and electrically or mechanically controlled.47

106. Controls in the cockpit consist of two side sticks, conventional rudder pedals and pedestal mounted controls and indicators.49

108. SEC (Spoilers and Elevator Computers) : These three computers achieve upper wing surfaces control, standby elevator and stabiliser control.

109. FAC (Flight Augmentation Computers) : These two computers achieve rudder control.

110. In addition the Flight Control Data Concentrator acquires data from the ELAC's and SEC's and sends this to the ECAM (Electronic Centralised Aircraft Monitor) - the flight deck screen displays and CFDS.

111. The Electrical Flight Control System (EFCS) includes the ELACs, SECs, FCDCs and vertical accelerometers.50

112. Fly By Wire (FBW) AIRBUS FBW System Arrangement 51

115. Self-monitoring capacity.

116. Monitoring channel: Each computer consists of two physically and electrically separated channels, one being dedicated to the control functions, the other to the monitoring functions.

117. Automatic power-on and pressure-on safety tests performed without movement of the surfaces.52

121. Elevators

122. Stabiliser (tailplane)

123. Roll Control

124. Ailerons

125. Spoilers

126. AutopilotThe trim actuator and yaw damper servo actuators are used to introduce the A/P signals. The trim actuator drives the mechanical control (and pedals) through the artificial feel. 55

127. Fly By Wire (FBW) 56 Figure : Flight Control System - General Arrangement

129. The ELAC and SEC also feed two computers and the FCDC. These monitor and analyze ELAC and SEC maintenance messages at power on (on ground), in-flight and after touch down.

130. It stores the data and delivers failure indications, eg stored failures, failure history, trouble shooting as well as failed LRUs to the Centralised Fault Display Interface Unit for onward transmission to the Maintenance Control DisplayUnit.57

132. The flight deck controls consist of a control column for control of the elevators with a hand wheel for control of the ailerons, flaps, and roll spoilers. The rudder bar controls the rudder.

133. These controls are provided with artificial feel and back-drive motors to move them in the correct sense when the system is in autopilot mode. An aileron trim actuator is also fitted in the system.58

135. Any computer/LRU can listen to any data on the bus and receive the data according to how its personality PROM (Programmable Read Only Memory) is programmed. In other words the computer's permanent memory knows what information on the data bus is for its use.59

137. The pilot's controls are connected via the Actuator Control Electronics (ACE) unit to the PCU. Other units such as the Primary Flight Computer (PFC) are connected into the system by the ARINC 629 bus. 60

139. The controls have artificial feel to simulate air loads on the control surfaces and trimming is achieved by biasing the system neutral by a trim unit actuator.61

141. When autopilot is engaged the back-drive actuator will move the pilots controls in response to autopilot commands. Whenever the autopilot is engaged the back-drive actuators are active.

142. When autopilot is selected the PCU is controlled by the ACE, PFC and Autopilot Flight Director Computer (AFDC) via the bus. The AFDC will also send an analogue signal to the back-drive actuator to move the flight deck controls to correspond to control surface movement. Thus the system simulates closely the characteristics of a conventional mechanical flying control system.62

144. The Global Positioning System (GPS) is a satellite navigation system providing accurate, three-dimensional position, velocity, and time information all over the world. GPS is a network of satellites that broadcasts ranging information, in addition to the satellite position, and time of transmission. 63

147. Space Segment segment

148. Satellites

149. Broadcast signals to user segment

150. Command segment

151. Control stations

152. Maintains correct operation of space segment

153. User Segment (airborne object)

154. GPS receivers

155. Military

156. Precision Positioning Service (PPS)

157. <18 meters

158. Highly accurate

159. Non – Military

160. Standard Positioning Service (SPS)

161. 15 – 25 meters

162. Degraded to 100 meters

163. Less Accurate than military65

165. 6 - 11 Satellites in view at 5 degrees or more above the horizon to users, anytime and anywhere in the world. 66

167. Frequency band,L2 - 1227.60 MHz: P(Y) code

168. The satellites transmit at two L-band frequencies to allow the detection of signal propagation delay in the ionosphere.

169. Each satellite's P-code and C/A code is a unique PRN code. The unique code is a pseudo-random sequence that allows all the satellites to transmit on the same frequency without creating radio interference.67

171. Universal Time – Co-ordinated UTC

172. Clock Corrections

173. Ephemeris Parameters

174. Orbital data giving satellite positions

175. Almanac data

176. Satellite housekeeping data

177. Transmitted on L band frequencies

178. L1 – 1.57542 GHz

179. L2 – 1.227 GHz

180. Transmissions are spectrum spread

181. All satellites use the same frequencies68

182. GlobalPositioning System : 69 Space Segment 3 – GPS Transmission

185. Control Segment 3 – Master Control Station

186. Located at Colorado Springs, USA

187. Controls all the control segment

192. Receive information from satellites- Accuracy of satellite clocks - Meteorological data - To calculate tropospheric signal delay - Measure ranges of all visible satellites - To calculate and predict orbits 73

198. satellite clock error

199. ephemeris error

200. receiver errors

201. atmospheric propagation error

202. multipath errors 77

204. Velocity

205. Distance travelled

206. Current Position2.Assist aircraft T/O, landing & taxiing 3. Gives 3 dimensional positioning 78

208. Components of IRS The complete IRS consists of: IRU (Inertial Reference Unit) MSU (Mode Selector Unit) ISDU (Inertial System Display Unit) 79

209. Inertial Reference System: 80

211. The ISDU enables the IRS to be initialized and their main navigation data to be displayed. The unit is an emergency means for these operations which are normally performed through the FMS.

212. The MSU allows the related IRS to be started up and the operation mode selection. Warning lights enables the system monitoring.

213. The IRU is the main component of this strap down inertial system. It houses 3 (three) accelerometers and 3 (three) ring laser gyros which detects the aircraft rotations and accelerations around its 3 (three) axes, and the computer which calculates attitude, direction, speed and reference position. 81

215. NAV MODE: Normal position for IRS operation. After alignment phase, the IRS will provide attitude, heading and position information to all peripherals

216. ATT MODE: Selection of this mode when the alignment is not complete. Only attitude and heading information is usable. The MSU is also used to annunciate status of the IRU. 82

219. The ISDU is connected to the IRU and allows their initialization. It is also used to display the main navigation data such as present position, ground speed, true heading, wind information and system status. It is designed to interface with discrete and digital inputs received from each IRU.

220. It can transmit discrete signals or digital messages to the IRU. The ISDU consists of a front-panel mounted display, two selector knobs: SYS DSPL and DSPL SEL and a keyboard. 84

221. Inertial Reference System: 85 Figure: Inertial Sensor Display Unit (ISDU)

223. TCAS I provides traffic advisories (TA) and proximity warning of nearby traffic to assist the pilot in the visual acquisition of intruder aircraft.

224. TCAS II provides traffic advisories and resolution advisories (RA), i.e., recommended escape maneuvers, in the vertical dimension to either increase or maintain the existing vertical separation between aircraft.

225. TCAS transmits to and receives signals from other airplanes to get altitude, range, and bearing data.86

226. Traffic Alert And Collision Avoidance System (TCAS) 87 Figure : TCAS airspeed coverage

228. TCAS computer

230. Traffic Alert And Collision Avoidance System (TCAS) 89 Figure TCAS Basic Operation

232. Proximate traffic shows as a solid white diamond; the altitude readout is in white text

233. Traffic advisory (TA) shows as a solid amber circle; the altitude readout is in amber text

234. Resolution advisory (RA) shows as a solid red square; the altitude readout is in red text.

235. Each traffic symbol has an altitude readout. A vertical motion arrow is also shown if the airplane vertical speed is greater than 500 feet per minute (fpm). 90