Avionics  Part  A                                                                      Khagendra  k.  yadav  

 1. What  is  need  of  defining  various  Avionics  architecture?  

Brought improvements in terms of increased performance, computing power, complexity and reliability, although all at an increase in cost. Other benefits included a decrease in weight, volume, power consumption and wiring. The key architectural steps during this time have been:

• Distributed analogue architecture; • Distributed digital architecture; • Federated digital architecture; • Integrated modular architecture; also digital.

2. Why  is  the  open  system  architecture  so  popular  in  the  modern  avionics  systems?  

     

 3. What  are  the  major  drivers  and  needs  for  Avionics?  

Major drivers for avionics are: • Capability • Reliability • Maintainability • Certificability • Survivability(military) • Availability • Susceptibility • vulnerability • Life cycle cost(military) or cost of ownership(civil) • Technical risk • Weight & power

Needs of Avionics:

• To  detect  and  process  the  data  about  environment  inside  and  outside  the            aircraft.

• To  derive  information  in  a  form  suitable  for  crew  utilization.  • To   accept   crew   inputs   and   combine   with   other   derived  

Information.  • To   activate   controls  within   the   aircraft   and   simulate   the   outside  

environment  as  dictated  by  mission  requirements  of  the  system    

4. What  are  the  advantages  of  HMD  over  HUD?  •  In  HMD  the  gimbaled  sensors  enables  the  pilot  to  watch  critical  data  in  the   helmet   in   the   directions   through   which   he/she   moves/looks,   thus  facilitating  him/her  to  watch  the  primary  data  always.  •  HMD  display   formats  are  very   similar   to   those  of  HUDs  except   for   the  addition   of   helmet-­‐pointing   azimuth   and   elevation   information   and  vectors   showing   where   the   last   target   of   interest   was   prior   to   looking  down  into  the  cockpit  or  searching  for  another  target.  

 5. Define Dead reckoning navigation system.

Dead reckoning (DR) is the process of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known or estimated speeds over elapsed time, and course. While traditional methods of dead reckoning are no longer considered primary means of navigation, modern inertial navigation systems, which also depend upon dead reckoning, are very widely used.

6. Differentiate  between  MIL  and  ARINC  standard  in  terms  of  BUS  speed?  

   

7. What is the need for two different speeds in ARINC 429 data bus?  Two different data rates are used in ARINC-429. They are 12-14.5 Kbits/sec(Low speed bus) and 100 Kbits/sec(High speed bus). Low speed bus is used for general-purpose, low criticality applications. High speed bus is used for transmitting large quantities of data or flight critical information.

8. Distinguish between pave pace and pave pillar architecture?  Pave   pillar-­‐ (1987)   This architecture is specifically targeted for advanced tactical fighters, and in general for all military aircraft applications. The PAVE PILLAR Architecture addresses those functions which could be implemented with common hardware and computer programs to allow adaptation to either air-to-air or air-to-ground missions. This programme questioned the black box approach to avionics. Pave Pillar architecture physically comprised a number of building blocks called common modules. Each module contained the circuitry to perform a complete digital processing function including interface control and health diagnosis. The common modules were developed from a limited very high-speed integrated circuit (VHSIC) chip set. A number of common module types could then be built up from a small family of VHSIC chips. Pave pace-

   

9. Name  the  few  types  of  CFDS?    

10. What  is  BIT?  (Built-in test equipment) The BITE is characterized primarily as a passive fault management and diagnosis built into airborne systems to support the

maintenance process. Built-in test equipment refers to multimeters, oscilloscopes, discharge probes, and frequency generators that are provided as part of the system to enable testing and perform diagnostics.

The term BIT often includes :- The detection of the fault. The accommodation of the fault (how the system actively responds to the fault). The annunciation or logging of the fault to warn of possible effects and/or aid in troubleshooting the faulty equipment.

 11. What  are  the  advantages  of  active  cooling  over  passive  cooling  system?  

 12. What  is  fault  tree  analysis?  

This analysis technique uses probability to assess whether a particular system configuration or architecture will meet the mandated requirements. For example, assume that the total loss of aircraft electrical power on-board an aircraft has catastrophic failure consequences as identified by the functional hazard analysis.Then the safety objective quantitative requirement established by FAR/JAR 25.1309 and as amplified in ARP 4754 will be such that this event cannot occur with a probability greater than 1 Å~ 10-9 per flight hour (or once per 1000 million flight hours). The ability of a system design to meet these requirements is established by an FTA using the following probability techniques.

 13. Define  ATLAS  

Abbreviated   Test   Language   for   All   Systems  (ATLAS)   is  a  MILSPEC  language   for   automatic   testing   of  avionics  equipment.   It   is   a  high-­‐level  computer   language  and   can   be   used   on   any   computer   whose  supporting  software  can  translate  it   into   the   appropriate  low-­‐level  instructions.    

 14. Write  the  specification  of  ARINC429  packing  standard?  

 15. Define the usage of avionics in space systems.

•  Fly-by-wire control systems were used for vehicle attitude and translation control. •  Sensors used around the aircraft for data acquisition. •  Redundancy system and autopilot. •  On board computers used in satellites for processing.

16. What are major drivers for avionics in civil transport aircraft?

•  Major drivers for avionics in civil transport aircraft are: i. Capability ii. Reliability iii. Maintainability iv. Certificability v. Cost of Ownership vi. Technical risk vii. Power and Weight

17. What is FBW? A fly-by-wire system actually replaces manual control of the aircraft with an electronic interface. The movements of flight controls are converted to electronic signals, and flight control computers determine how to move the actuators at each control surface to provide the expected response. The actuators are usually hydraulic, but electric actuators have also been used.

18. What is an auto pilot? An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. Most people understand an autopilot to refer specifically to aircraft, but self-steering gear for ships, boats, space craft and missiles are sometimes also called by this term.

19. What is HOTAS? HOTAS, an abbreviation for Hands On Throttle-And-Stick, is the name given to the concept of placing buttons and switches on the throttle stick and flight control stick in an aircraft's cockpit, allowing the pilot to access vital cockpit functions and fly the aircraft without having to remove his hands from the throttle and flight controls. Having all switches on the stick and throttle allows the pilot to keep his "hands on throttle-and-stick", thus allowing him to remain focused on more important duties than looking for controls in the cockpit.

20. What is meant by DVI?

The Digital Visual Interface (DVI) is a video interface standard designed to provide very high visual quality on digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an industry consortium, the Digital Display Working Group (DDWG).