Digital

• SOFTWARE MANAGEMENT CONTROL
• Software Management Control

  Includes a thorough definition and documentation of the aircraft software development process in order to avoid the catastrophic effects of unapproved software changes being uploaded onboard aircraft computers that could cause aircraft loss and multiple fatalities
• Required software documentations


  • Airworthiness certification plans
  • Software quality assurance plan
  • Software configuration management plan
  • Configuration control procedures
  • Software code standard
  • Software design standard
  • Software requirements standard
  • Software development plan
  • Software verification plan
  • Software design document
  • Software requirements document
  • Traceability
  • Test cases and test procedures
  • Verification results
  • Quality assurance records
  • Configuration management records
  • Problem reports
  • Software accomplishments summary
• Airworthiness requirements


  "Software Considerations in Airborne Systems and Equipment Certification" is a standard document dealing with the safety of software used in aircraft systems
• It was jointly published in 1992 by the Radio Technical Commission for Aeronautics (RTCA) as DO-178B and European Organization for Civil Aviation Equipment (EUROCAE) as ED-12B
• Software criticality levels


  • Level A: Catastrophic - Prevents continued safe flight or landings. Failure may cause multiple fatalities and loss of aircraft
  • Level B: Hazardous/Severe - Failure has large negative impact on safety or performance. May cause serious or fatal injuries to a smaller number of passengers
  • Level C: Major - Failure significantly reduces safety margin, impairs crew efficiency, discomfort or possible injuries to passengers
  • Level D: Minor - Failure reduces the aircraft safety margins, but well within crew capabilities. May include passenger inconvenience such as a routine flight plan change
  • Level E: No Effect - Failure has no impact on the safety or aircraft operation
• ARINC 653


  A software specification for space and time partitioning in a real-time operating system that allows a processor to host multiple software applications of different criticality levels on the same processor
• DO-178C


  The newer standard that contains several supplements that map closely with current industry software development and verification practices
• DO-178C supplements


  • Software Tool Qualifications (DO-330)
  • Model-Based Development and Verification (DO-331)
  • Object-Oriented Technology (DO-332)
  • Formal Methods (DO-333)
• Electromagnetic interference (EMI)


  The interference caused by one electrical or electronic device to another by the electromagnetic fields set up by its operation
• Unintended electromagnetic waves can cause severe disruption to aircraft system operation.
• Radiative coupling


  The source emits or radiates an electromagnetic field that propagates across an open space and is received by the unintended victim.

  
• Inductive coupling


  A varying magnetic flux field from one conductor comes in close proximity to another conductor producing an induced current.
• Capacitive coupling


  A varying electric field exists between two adjacent conductors inducing a voltage change between the conductors through a dielectric, such as air.
• Conductive coupling


  The coupling path between the source and the victim is formed by direct contact through perhaps a wire or metal enclosure.
• High-Intensity Radiated Field (HIRF)


  The result of a multitude of intentional and non-intentional electromagnetic sources that currently exist in the world
• The power density of the electromagnetic field is sufficient to adversely affect living organisms or degrade equipment performance.
• HIRF interference can also be caused by high power radio and microwave towers, including ATC primary surveillance radars.
• Care must be taken to prevent mutual HIRF interference between transmitters of one system and receivers of another system.
• Lightning protection


  • Aircraft have static wicks installed at the trailing edge of the horizontal and vertical surfaces to dissipate electromagnetic energy on the surface of the skin back into the atmosphere.
• Electromagnetic Compatibility (EMC)


  The goal is to eliminate or reduce the harmful effects of unintended Electromagnetic Interference.
• EMI should be identified and eliminated, or at least reduced as much as possible at the source


  By eliminating coupling paths through proper equipment layout, shielding, filtering, and grounding techniques.
• Electronic Instrument System (EIS)


  Includes Electronic Flight Instrumentation System (EFIS), Engine Indication and Crew Alerting System (EICAS), Electronic Centralized Aircraft Monitor (ECAM), Integrated Modular Avionics (IMA) Information Systems
• Integrated Modular Avionics (IMA) Information Systems


  • Used to control onboard communications, navigation, and surveillance systems and to provide information to be displayed on the EIS
  • Provides a more unified approach to avionics design resulting in considerably less volume and weight due to the sharing of resources
• Aircraft Communication Addressing and Reporting System (ACARS)


  • A digital data link for the transmission of short text messages between aircraft and ground stations to relieve the crew from having to call in their times and to provide more accurate reporting
  • OOOI is an automated message recorded by aircraft systems that log the following times: pushback, take-off, landing, and arrival at the gate
• Global Positioning System (GPS)


  • A space-based navigation system that was launched by the U.S. Department of Defense in the early 1990s
  • Consists of three segments: a space system segment, a control system segment, and a user system segment
  • By using the distances from at least three satellites, the GPS receiver can triangulate the user's current position. With measurements from four satellites, the GPS receiver can determine elevation as well

  
• Traffic Alert and Collision Avoidance System (TCAS)


  • A transponder based air-to-air traffic monitoring and alerting system
  • TCAS I identifies traffic in a 35 to 40 mile range of the aircraft
  • TCAS II analyzes the projected flight path of approaching aircraft
• Fly-by-wire


  • Replaces the hydromechanical flight control system in its entirety with an electrical interface
  • The movements of the pilot's controls are converted to electrical signals and transmitted by wires to the flight control computers
• Cabin Systems


  • In the 1970's, In-Flight Entertainment (IFE) systems were limited to prerecorded audio tapes or compact discs that passengers listened to through their individual earphones or headsets
  • Later, when flat panel LCD screens became available, passengers could watch VCR video tapes on their seat back color displays
  • Passengers today want more than pre recorder video
• Give the meaning of OOOI

  • out of the gate
  • off the ground
  • on the ground
  • in the gate
• Tcas 1 issues?


  Traffic advisory
• Tcas 2 issues?

  Advisory circular
• Space system segment has ?

  6 planes, each plane has 4 sattelite
• 4 ways that electromagnetic field can be coupled

  • radiative
  • inductive
  • capacitive
  • conductive
• Ways to eliminate coupling paths

  • proper equipment layout
  • shielding
  • filtering
  • grounding technique
• Types of fields

  • electric field
  • magnetic field
• 2 types of static wicks

  • carbon fiber
  • mettalic