Session 5 @ SOAR by Avembsys

The fifth session began with introduction to operators, their precedences and associativity, branching and looping constructs in C were discussed by one of our friend.  The SME then took over the session and queried about the progress in the projects assigned to us.  The discussion continued, with introduction to avionics, avionic systems, its requirements, regulators and advisory agencies and examples of avionics system.
 
Avionics is the combination of electronic and electromechanical system and sub system installed in an aircraft or attached to it.  Avionics must be integrated in the conceptual design phase.  Avionics system requirements are as follows:

• Safety of flight
• Mission of aircraft
• Life cycle cost/cost of ownership
• Certification is a major factor in avionics

Federal Aviation Administration(FAA) certifies civil aviation in U.S,  Center for Military Airworthiness and Certification(CEMILAC) certifies military aircraft.  Avionics placement on Multipurpose aircraft includes GPS, Military IFF, MLS, DME (distance measuring equipment), ATC transponder, Radio altimeter, VHF, ADF(automatic direction finder), TACAN, UHF SATCOM. 

 Avionics System in all aircraft:

• Navigation System
• Communication
• Flight Control
• Engine Control
• Flight Management
• Sub system monitoring and control
• Collision Avoidance
• Weather Detection
• Emergency Location Transmitter(ELT)

Avionics System in military aircraft:

• Radar,Infrared and other target sensors
• Weapon Management
• Electronic Countermeasures
• Mission Planning
• Formation Flight

Regulatory and Advisory Agencies:

• ICAO   (International Civil Aviation Organization)
• FAA     (Federal Aviation Administration)
• FCC      (Federal Communications Commission)
• RTCA   (Requirements and Technical Concepts in Aviation) 
• ARINC (Aeronautical Radio Incorporated)
• SAE      (Society of Automotive Engineers)
• IEEE    ( Institute of Electrical and Electronics Engineers)
• JAA      (European Joint Aviation Authorities)
• EUROCAE (European Organization of Civil Aviation Equipment)
• DGCA   (Directorate General of Civil Aviation)

Aircraft and Mission drive the avionics system design.  Mission Segment(Taxi, Take off, Climb, Cruise).  Functional decomposition can be as follows:

• Mission
• Mission Segment
• Segment Requirement 
• Aviation Requirement

Avionics system interact with four types of data: Fresh and Valid, Fresh but Invalid, Stale but Valid and Stale and Invalid. Every 50msec data is retrieved from sensors.  We also saw certain professional codes and the standards used for professional coding such as AIRBUS C Coding Standard which is one of the highest standard. 
 

Examples of avionics system: EGPWS and TCAS

EGPWS  (Enhanced Ground Proximity Warning System) is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle.

7 modes of EGPWS:

• Excessive descent rate
• Excessive Closure to Terrain
• Altitude loss after Take off
• Unsafe Terrain Clearance
• Excessive glides scope deviation
• Advisory call out/bank angle
• Wind shear aircraft

TCAS (Traffic Collision Avoidance System) and the types of alerts in TCAS such as Traffic Advisories(assist the pilot in detecting the intruder) and Resolution Advisories (to resolve mid air collisions) and TCAS symbols were also discussed. The class was over all interesting and informative, eagerly waiting for the next session.