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AE2401 Avionics ANNA UNIVERSITY QUESTION BANK, QUESTION PAPER, IMPORTANT QUESTIONS 2 MARKS and 16 MARKS QUESTIONS

Wednesday, June 29, 2011 ·


AE2401 Avionics
1. What is avionics?
2. Explain the advantage of using avionics in civil aircraft.
3. Explain the advantage of using avionics in military aircraft.
4. Give the general advantage of Avionics over the conventional aircraft system.
5. Define the usage of avionics in space systems.
6. Give few examples of integrated avionics system used in weapon system.
7. Give few examples of integrated avionics system used in civil airlines.
8. Explain “illities” of Avionics system.
9. Give various systems where the avionics used in aircrafts.
10. Explain the steps involved in design of avionics system.
11. Give few examples of Standards used in design of avionics system.
12. What are digital computers?
13. Give the need for standard documents in the design of avionics system.
14. What is a volatile memory and give examples?
15. Give the advantages of digitization.
16. What are major drivers for avionics in civil transport aircraft?
17. What is aliasing?
18. Differentiate between volatile and non volatile memories.
19. How are reliability and maintainability related to each other?
20. What is microprocessor?
21. Explain the usage of microprocessors in Avionics system.
22. Explain the registers of microprocessor?
23. What is Accumulator? 24. Explain the types of memories?
25. Explain the major components of microprocessor.
26. What is fetching?
27. Give few avionics architecture.
28. Explain Federated architecture.
29. Explain centralized architecture.
30. How is federated architecture different from centralized architecture?
31. Explain MIL-STD 1553B components?
32. Explain the status word of MIL-STD 1553B.
33. Explain the bus controller and Remote terminal of MIL-STD 1553B.
34. Explain ARINC 429 standard.
35. Explain ARINC 629 standard.
36. Differentiate between Civil and military communication standards.
37. Differentiate between ARINC 429 and ARINC 629.
38. Differentiate between MIL and ARINC standard in terms of RT?
39. Differentiate between MIL and ARINC standard in terms of BUS speed?
40. What is the need for two different speeds in ARINC 429 data bus?
41. What is an auto pilot?
42. What is brick walling or partitioning in avionics architecture?
43. Define Glass cockpit.
44. Define plasma panel.
45. Differentiate LED & LCD.
46. Explain CRT and its usage in aircraft displays.
47. What is meant by DVI?
48. What are MFD and its significance in Aircraft?
49. Explain the advantage of HMD over MUD?
50. Explain MFK and its usage.
51. What is HOTAS?
52. Explain HUD?
53. What is usage of night vision goggles?
54. Explain advantage of EL over Plasma display. 55. Explain the need of communication system in airline.
56. Explain Navigation.
57. Explain the types of Navigation.
58. Explain Dead reckoning type of navigation.
59. What is INS?
60. What are different types of INS?
61. What is GPS?
62. Explain about P and C/A codes.
63. Compare INS and GPS.
64. What is Flight control system?
65. What is Actuator?
66. Explain different types of actuator.
67. What is FBW?
68. What is FBL?
69. Explain the advantage of FBW over conventional FCS.
70. Explain FBW over FBL.
71. What is strap down Navigation?
72. What is FMS?
73. What is meant by jammers in electronic warfare?
74. Give the difference between ECCM and ECM.
75. Explain RADAR.
76. Explain Certification.
77. Explain V & V
78. Explain Reliability.
79. Explain maintainability.
80. Explain the steps of certification.
81. Explain the document support for Certification.
82. Explain Electronic warfare.
83. Explain the advantage of GPS over conventional navigation.
84. Explain the specific advantages of INS.
85. Explain Gimbaled INS. PART B – (16 marks)
1. i) Explain the need of avionics in Civil and military aircrafts.
ii) Explain few Integrated Avionics system and weapon system.
2. i) What are the major design drivers for avionics system?
ii) Describe the various ‘illities’ in Avionics systems.
3. With a neat block diagram explain the integration of different avionics system.
4. i) Explain clearly the top down design procedure that is adopted in Avionics system
   design.
ii) List the factor on which Avionics design is evaluated and explain each factor in
    brief.
5. Explain the various layers of Avionics systems used in a typical airplane with a neat
sketch.
6. Explain the design and technologies involved in avionics system and the standards
used for it.
7. With a neat sketch explain 8085 microprocessor architecture in detail.
8. i) Draw the functional representation of ROM memory cell and explain the concept
underlying the ROM.
ii) Describe with a block schematic how a digital computer can be used to measure
analog signal
9. Explain the interference of seven segment LED with the microprocessor to display a
binary data.
10. Compare the memory mapped I/O and peripheral mapped I/O in Microprocessor.
11. Discuss the various avionics architecture in detail.
12. Explain the ARINC 429 data bus in detail.
13. Explain the ARINC 629 data bus in detail.
14. Explain MIL STD 1553 B data bus in detail  bring out clearly the bus architecture,
protocol, word ad message formats and coupling methods.
15. i) List the evolution of avionics architecture starting from first generation to fourth
generation.
ii) Describe in detail about one of the  third generation Avionics Architecture with
block schematics. 16. a) Compare and contrast the display  technologies CRT,LED,LCD,EL and plasma
panel
b) What are the various types of CRTs used in civil and military aircraft and explain
them in detail.
 17.  a) Explain the basic principle of HUD and what are its limitations?
           How are they overcome in HMD?
        b) what are special features of DVI?
 18.  a) Describe the layout of a cockpit.
        b) Describe voice recognition & speech synthesis technology.
 19. What is navigation system and explain the various types of navigation with examples.
            20. Explain MFKs, HMD, HUD and HDD in detail.
 21. Describe a FBW flight control system and its characteristics and redundancy concept
                  in detail.
22. Explain the operation of inertial navigation system and explain its two types of
      construction.
23. What is FBW explain its salient features with the block diagram in comparison with
       the conventional flight control system.
24. What is FBL and explain its salient features with block diagram in comparison with
       FBW.
25. a) what is the need for a communication system in aircraft?
      b) Explain one of the most modern reliable communication systems used in aircraft
          with a block schematic.
26. What is GPS and explain the working of it with codes of communication used for
       locating the object.
27. Explain in detail about Radar Electronic war fare and its salient features and its usage.
28. Explain Certification and explain the various steps involved in certification of
      avionics system.
29. What is Dead reckoning navigation system and explain any one type in detail.
30. Explain Conventional Flight control system and advantage of FBW to overcome the
      disadvantage of Conventional FCS. COMPILATION OF
AVIONICS
   TWO MARK QUESTIONS
Complied by
             
   Bharanidharan Asokan [1-59]
                                                                                  SK Karthick [60-82]
Guided by
M.Magesh
Lecturer
Department of Aeronautical Engineering,
Rajalakshmi Engineering College, Chennai. 1. What is avionics?
Avionics means "aviation electronics". It comprises electronic systems for use on
aircraft, artificial satellites and  spacecraft, comprising communications,
navigation and the display and management of multiple systems.
2. Explain the advantage of using avionics in civil aircraft.
• Reducing the crew workload by automating tasks.
• The reduction in weight can be translated to increased passengers or long
range.
• To enable the flight crew to carry out the aircraft mission safely and
efficiently.
• All weather operation and reduction in maintenance costs.
3. Explain the advantage of using avionics in military aircraft.
• A single seat fighter or strike aircraft is lighter and Costs less than an
equivalent two seat version.
• Elimination of the second crew member (navigator/observer/crew
member) results in reduction in training costs.
• Improved aircraft performance and control and handling and reduction in
maintenance costs
• Secure communication.
4. Give the general advantage of Avionics over the conventional aircraft system.
• Increased safety
• Air traffic control requirements
• All weather operation
• Reduction in fuel consumption
• Improved aircraft performance and control and handling and reduction in
maintenance costs
5. 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.
6. Explain “illities” of Avionics system.
• Capability
• Reliability
• Maintainability
• Certificability • Survivability(military)
• Availability
• Susceptibility
• vulnerability
• Life cycle cost(military) or cost of ownership(civil)
• Technical risk
• Weight & power
7. Give various systems where the avionics used in aircrafts.
• Aircraft intercoms
• Wide Area Augmentation System
• Terrain awareness and warning system
• Ground proximity warning system
• Aircraft collision avoidance systems
• Display systems
• Traffic Collision Avoidance System
8. Explain the steps involved in design of avionics system.
• The three stages are:
i. Conceptual design - What will it do?
ii. Preliminary design - How much will it weigh?
iii. Detailed design - How many parts will it have?
9. What are digital computers?
A device that processes numerical information; more generally / any device that
manipulates symbolic information according to specified computational
procedures is called as digital computers. The term digital computer—or simply,
computer—embraces calculators, computer workstations, control computers
(controllers) for applications such as domestic appliances and industrial processes.
10. What is a volatile memory and give examples?
Volatile memory, also known as volatile  storage, is computer memory that
requires power to maintain the stored  information, unlike non-volatile memory
which does not require a maintained power supply. It has been less popularly
known as temporary memory.
Most forms of modern random access memory (RAM) are volatile storage
11. What is aliasing?
In computing, aliasing describes a situation in which a data location in memory
can be accessed through different symbolic names in the program. Thus,
modifying the data through one name implicitly modifies the values associated to
all aliased names, which may not be expected by the programmer. As a result,
aliasing makes it particularly difficult to understand, analyze and optimize programs. Aliasing analyses intend to make and compute useful information for
understanding aliasing in programs.
12. Differentiate between volatile and non volatile memories.
Volatile memory: The data is lost on reboot, you will lost all of your data when
your electricity go out.. This is the ram memory. Random-access-memory.
Non-volatile memory: The data is saved to a hard drive or flash drive, or it could
be a hard coded chip. This is rom memory. Read-only-memory. All data that
stored in this type of memory will retain when you shutdown your computer.
13. What is microprocessor?
A complex microcircuit (integrated circuit) or set of such chips that carries out the
functions of the processor of an information technology system; that is, it contains
a control unit (and clock), an arithmetic and logic unit, and the necessary registers
and links to main store and to peripherals.
14. Explain the registers of microprocessor?
In computer architecture, a processor register (or general purpose register) is a
small amount of storage available on the CPU whose contents can be accessed
more quickly than storage available elsewhere. Typically, this specialized storage
is not considered part of the normal memory range for the machine. Processor
registers are at the top of the memory hierarchy, and provide the fastest way for a
CPU to access data.
15. What is Accumulator?
In a computer's central processing unit (CPU), an accumulator is a register in
which intermediate arithmetic and logic results are stored. Without a register like
an accumulator, it would be necessary  to write the result of each calculation
(addition, multiplication, shift, etc.) to main memory, perhaps only to be read
right back again for use in the next operation. Access to main memory is slower
than access to a register like the accumulator because the technology used for the
large main memory is slower (but cheaper) than that used for a register.
16. Explain the types of memories?
Volatile memory, also known as volatile  storage, is computer memory that
requires power to maintain the stored  information, unlike non-volatile memory
which does not require a maintained power supply. It has been less popularly
known as temporary memory. Most forms of modern random access memory
(RAM) are volatile storage, including dynamic random access memory (DRAM)
and static random access memory (SRAM). Non-volatile memory, nonvolatile memory, NVM or non-volatile storage, is
computer memory that can retain the stored information even when not powered.
Examples of non-volatile memory include read-only memory, flash memory,
most types of magnetic computer storage  devices (e.g. hard disks, floppy disks,
and magnetic tape), optical discs, and early computer storage methods such as
paper tape and punch cards.
17. Give few avionics architecture.
• First Generation Architecture ( 1940’s –1950’s)
i. Disjoint or Independent Architecture ( MiG-21)
ii. Centralized Architecture (F-111)
• Second Generation Architecture ( 1960’s –1970’s)
i. Federated Architecture   (F-16 A/B)
ii. Distributed Architecture (DAIS)
iii. Hierarchical Architecture (F-16 C/D, EAP)
• Third Generation Architecture ( 1980’s –1990’s)
i. Pave Pillar Architecture ( F-22)
• Fourth Generation Architecture (Post 2005)
i. Pave Pace Architecture-  JSF
ii. Open System Architecture      
18. Explain Federated architecture.
In FEDERATED ARCHITECTURE Data conversion occurs at the system  level
and the datas are send as digital form – called Digital Avionics Information
Systems(DAIS). Several standard data processors are often used to perform a
variety of Low – Bandwidth functions  such as navigation, weapon delivery ,
stores management and flight control Systems are connected in a Time – Shared
Multiplex Highway. Resource sharing occurs at the last link in the information
chain – via controls and displays.
19. Explain centralized architecture.
As the digital technology evolved, a central computer was added to integrate the
information from the sensors and subsystems. The central computing complex is
connected to other subsystems and sensors through analog, digital, synchro and
other interfaces. When interfacing with computer a variety of different
transmission methods, some of which required signal conversion (A/D) when
interfacing with computer. Signal conditioning and computation take place in one
or more computers in a LRU located in an avionics bay ,with signals transmitted
over one way data bus. Data are transmitted from the systems to the central
computer and the DATA CONVERSION TAKES PLACE AT THE CENTRAL
COMPUTER. 20. How is federated architecture different from centralized architecture?
In FEDERATED ARCHITECTURE Data conversion occurs at the system level
and the data are send as digital form  – called Digital Avionics Information
Systems (DAIS). It is fully digital.
In centralized architecture Data conversion takes place at the central computer.
Analog wires are used.
21. Explain MIL-STD 1553B components?
• BUS CONTROLLER
• BUS MONITOR
• REMOTE TERMINAL
• TRANSMISSION MEDIA
22. Explain the status word of MIL-STD 1553B.
Status words are transmitted by the RT in response to command messages from
the BC and consist of:
• 3 bit-time sync pattern (same as for a command word)
• 5 bit address of the responding RT
• 11 bit status field
• 1 parity check bit.
The 11 bits in the status field are used to notify the BC of the operating condition
of the RT and subsystem.
23. Explain the bus controller and Remote terminal of MIL-STD 1553B.
There is only one Bus Controller at a time on any MIL-STD-1553 bus. It initiates
all message communication over the bus.
A Remote Terminal can be used to provide:
• An interface between the MIL-STD-1553B data bus and an attached
subsystem
• A bridge between a MIL-STD-1553B bus and another MIL-STD-1553B
bus.
24. Explain ARINC 429 standard.
ARINC 429 is the technical standard for the predominant avionics data bus used
on most higher-end commercial and transport aircraft. It defines the physical and
electrical interfaces  of a two-wire data bus and a  data protocol to support an
aircraft's avionics local area network. 25. Explain ARINC 629 standard.
ARINC 629 is a multi-transmitter protocol where many units share the same bus.
It was a further development of ARINC 429 especially designed for the Boeing
777
26. 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.
27. What is brick walling or partitioning in avionics architecture?
The purpose of partitioning is fault containment: a failure in one partition must
not propagate to cause failure in another partition. The function in a partition
depends on the correct operation of its processor and associated peripherals, and
partitioning is not intended to protect against their failure—this can be achieved
only by replicating functions across multiple processors in a fault-tolerant
manner.
28. Define Glass cockpit.
A glass cockpit is an aircraft cockpit that features electronic instrument displays.
Where a traditional cockpit relies on numerous mechanical gauges to display
information, a glass cockpit uses several  displays driven by flight management
systems, that can be adjusted to display flight information as needed. This
simplifies aircraft operation and navigation and allows pilots to focus only on the
most pertinent information. They are also popular with airline companies as they
usually eliminate the need for a flight engineer. In recent years the technology has
become widely available in small aircraft.
29. Define plasma panel.
A plasma display panel (PDP) is a type of flat panel display common to large TV
displays (32" inches or larger). Many tiny cells between two panels of glass hold a
mixture of noble gases. The gas in the cells is electrically turned into a plasma
which then excites phosphors to emit light.
30. Differentiate LED & LCD.
LEDs are based on the semiconductor diode. When the diode is forward biased
(switched on), electrons are able to recombine with holes and energy is released in
the form of light. This effect is called electroluminescence and the color of the
light is determined by the energy gap of the semiconductor. LEDs present many
advantages over traditional light sources including lower energy consumption,
longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise  current and heat
management than traditional light sources.
A liquid crystal display (LCD) is a thin, flat panel used for electronically
displaying information such as text,  images, and moving pictures Among its
major features are its lightweight construction, its portability, and its ability to be
produced in much larger screen sizes than are practical for the construction of
cathode ray tube (CRT) display technology. Its low electrical power consumption
enables it to be used in battery-powered electronic equipment. It is an
electronically-modulated optical device made up of any number of pixels filled
with liquid crystals and arrayed in front of a light source (backlight) or reflector to
produce images in color or monochrome.
31. Explain CRT and its usage in aircraft displays.
The cathode ray tube (CRT) is a vacuum tube containing an electron gun (a
source of electrons) and a fluorescent screen, with internal or external means to
accelerate and deflect the electron beam, used to create images in the form of light
emitted from the fluorescent screen.
32. 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). It is designed for
carrying uncompressed digital video data to a display.
33. What are MFD and its significance in Aircraft?
A Multi-function display (MFD) is a small screen  (CRT  or  LCD)  in  an  aircraft
surrounded by multiple buttons that can be used to display information to the pilot
in numerous configurable ways. Often an MFD will be used in concert with a
Primary Flight Display. MFDs are part of the digital era of modern planes or
helicopter. The first MFD were introduced by airforces. The advantage of an
MFD over analog display is that an MFD does not consume much space in the
cockpit.
Many MFDs allow the pilot to display  their navigation route, moving map,
weather radar, NEXRAD, GPWS, TCAS and airport information all on the same
screen.
34. 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.
35. Explain HUD?
A head-up display, or abbreviated as  HUD, is any transparent display that
presents data without requiring the user to look away from his or her usual
viewpoint. The origin of the name stems from the user being able to view
information with his head "up" and  looking forward, instead of angled down
looking at lower instruments. Although they were initially developed for military
aviation, HUDs are now used in commercial aircraft, automobiles, and other
applications.
36. Explain Navigation.
Navigation is the process of reading, and controlling the movement of a craft or
vehicle from one place to another. It is also the term of art used for the specialized
knowledge used by navigators to perform navigation tasks. The word navigate is
derived from the Latin "navigare", meaning "to sail".All navigational techniques
involve locating the navigator's position compared to known locations or patterns.
37. Explain the types of Navigation.
• Dead reckoning
• Navigation by Piloting
• Celestial navigation
• Electronic navigation
38. Explain Dead reckoning type of navigation.
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.
39. What is INS?
An Inertial Navigation System (INS) is  a navigation aid that uses a computer,
motion sensors (accelerometers) and  rotation sensors (gyroscopes) to
continuously calculate via dead reckoning the position, orientation, and velocity
(direction and speed of movement) of  a moving object without the need for
external references. It is used on vehicles such as ships, aircraft, submarines,
guided missiles, and spacecraft. 40. What are different types of INS?
It is of two different configurations based on the inertial sensor placement. They
are
    a. Stable or Gimballed platform.
    b. Strap down platform
41. What is GPS?
The Global Positioning System (GPS) is a U.S. space-based global navigation
satellite system. It provides reliable positioning, navigation, and timing services to
worldwide users on a continuous basis in all weather, day and night, anywhere on
or near the Earth. GPS is made up of three parts: between 24  and 32 satellites
orbiting the Earth, four control and monitoring stations on Earth, and the GPS
receivers owned by users. GPS satellites broadcast signals from space that are
used by GPS receivers to provide three-dimensional location (latitude, longitude,
and altitude) plus the time.
42. Explain about P and C/A codes.
Binary data that is modulated or "superimposed" on the carrier signal is referred
to as Code. Two main forms of code  are used with NAVSTAR GPS: C/A or
Coarse/Acquisition Code (also known as  the civilian code), is modulated and
repeated on the L1 wave every millisecond; the P-Code, or Precise Code, is
modulated on both the L1 and L2 waves and is repeated every seven days. The
(Y) code is a special form of P code used to protect against false transmissions;
special hardware, available only to the U.S.government, must be used to decrypt
the P(Y) code.
43. What is Flight control system?
An aircraft flight control system consists of flight control surfaces, the respective
cockpit controls, connecting linkages, and the necessary operating mechanisms to
control an aircraft's direction in flight. Aircraft engine controls are also considered
as flight controls as they change speed.
44. What is Actuator?
An actuator is a mechanical device for moving or controlling a mechanism or
system. An actuator typically is a mechanical device that takes energy, usually
created by air, electricity, or liquid, and converts that into some kind of motion.
45. Explain different types of actuator.
• plasma actuators
• pneumatic actuators
• electric actuators
• hydraulic cylinders, • linear actuators

46. 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.
47. Explain the advantage of FBW over conventional FCS.
• Care free maneuvering characteristics  
• Continuous automatic stabilization of the aircraft by computer control of
the control surfaces
• Auto pilot integration
• Good consistent handling which is sensibly constant over a wide flight
envelope and range of load conditions
• Enables a lighter, higher performance aircraft designed with relaxed
stability
48. What is strap down Navigation?
Strapdown systems have all their sensors mounted on a platform that changes
orientation like the plane. Instead of mechanical gyros to hold it level, it has three
more accurate gyros that sense the orientation of the system. Additionally, it has
the same three acceleration sensors.
Whereas the gimballed system just senses the orientation of the platform to get
the aircraft's attitude, the strapdown systems have three gyroscopes that sense the
rate of roll, pitch, and yaw. It integrates them to get the orientation, then
calculates the acceleration in each of the same axes as the gimballed system. Due
to the sensing of the rate of rotation, rather than just holding a platform level, very
accurate and sensitive gyroscopes are needed.
49. What is FMS?
A Flight Management System is a fundamental part of a modern aircraft in that it
controls the navigation. The flight management system (FMS) is the avionics that
holds the flight plan, and allows the pilot to modify as required in flight. The FMS
uses various sensors to determine the aircraft's position. Given the position and
the flight plan, the FMS guides the aircraft along the flight plan. The FMS is
normally controlled through a small screen and a keyboard.
50. What is meant by jammers in electronic warfare?
Electronic jamming is a form of Electronic Warfare where jammers radiate
interfering signals toward an enemy's  radar, blocking the receiver with highly concentrated energy signals. The two main technique styles are noise techniques
and repeater techniques.
51. Give the difference between ECCM and ECM.
Electronic countermeasures (ECM) are a  subsection of electronic warfare which
includes any sort of electrical or electronic device designed to trick or deceive
radar, sonar, or other detection systems like IR (infrared) and Laser. It may be
used both offensively or defensively in any method to deny targeting information
to an enemy. The system may make many separate targets appear to the enemy, or
make the real target appear to disappear or move about randomly. It is used
effectively to protect aircraft from guided missiles. Most air forces use ECM to
protect their aircraft from attack.
Electronic counter-countermeasures (ECCM) is a part of electronic warfare which
includes a variety of practices which attempt to reduce or eliminate the effect of
electronic countermeasures  (ECM) on electronic sensors aboard vehicles, ships
and aircraft and weapons such as missiles. ECCM is also known as electronic
protective measures (EPM), chiefly in  Europe. In practice, EPM often means
resistance to jamming.
52. Explain RADAR.
Radar is an object detection system that uses electromagnetic waves to identify
the range, altitude, direction, or speed of both moving and fixed objects such as
aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR
was coined in 1941 as an acronym for RAdio Detection And Ranging. A radar
system has a transmitter that emits microwaves or radio waves. These waves are
in phase when emitted, and when they come into contact with an object are
scattered in all directions. The signal is  thus partly reflected back and it has a
slight change of wavelength (and thus frequency) if the target is moving.
Although the signal returned is usually very weak, the signal can be amplified
through use of electronic techniques in the receiver and in the antenna
configuration. This enables radar to  detect objects at ranges where other
emissions, such as sound or visible light, would be too weak to detect.
53. Explain Certification.
Certification refers to the confirmation of certain characteristics of an object,
person, or organization. This confirmation is often, but not always, provided by
some form of external review, education, or assessment.
54. Explain V & V
Verification and validation is the process of checking that a product, service, or
system meets specifications and that it fulfills its intended purpose. These are
critical components of a quality management system such as ISO 9000. Sometimes preceded with "Independent" (or IV&V) to ensure the validation is
performed by a disinterested third party.
55. Explain Reliability.
• The idea that something is fit for purpose with respect to time;
• The capacity of a device or system to perform as designed;
• The resistance to failure of a device or system;
• The ability of a device or system  to perform a required function under
stated conditions for a specified period of time;
• The probability that a functional unit will perform its required function for
a specified interval under stated conditions.
• The ability of something to "fail well" (fail without catastrophic
consequences)
56. Explain maintainability.
The probability that a failed system can be made operable in a specified interval
or downtime is called as maintainability.
57. Explain Electronic warfare.
Electronic warfare (EW) refers to  any action involving the use of the
electromagnetic spectrum or directed energy to control the spectrum or to attack
the enemy. The purpose of electronic warfare is to deny the opponent the
advantage of, and ensure friendly unimpeded access to, the EM spectrum. EW can
be applied from air, sea, land, and space by manned and unmanned systems, and
can target communication, radar, or other services. EW includes three major
subdivisions: Electronic Attack (EA), Electronic Protection (EP), and Electronic
warfare Support (ES).
58. Explain the specific advantages of INS.
• It is the self contained, autonomous and unjammable.
• It is faster than the data given by the GPS.
• INS is very accurate over the short distance.
59. Explain Gimbaled INS.
Gimbaled systems have a platform in the device that is mounted in gimbals. This
device has 2 or more mechanical gyroscopes (not likely there are more than 3)
that keep this platform level. On the platform, in addition to the gyroscopes, are
usually three accelerometers, one in each direction. This was the earlier type of
INS. It does not need accurate gyroscope orientation sensing, they only need
mechanical gyroscopes to keep a platform level -- a much less demanding task for
the gyroscopes. Additionally, since the  accelerometers are already oriented
(usually north/south, east/west, and up/down) the actual integration to obtain
velocity and then position can be done by simpler, analog electronics. 60. Give few examples of integrated avionics system used in weapon system.
• Hemet Mounted Display (HMT)
• Head Level Display (HLD)
• Night Vision Goggles (NGV)
• Forward Looking Infra Red Displays (FLIR)
61. Give few examples of Standards used in design of avionics system.
• Military standards - MIL-STD-1629A (Hardware FMEA), MILSTD-882 (systems safety program requirements)
• ARINC 429, 629 (Civilian a/c data bus) and MIL-STD-1553A, 1773
(Military a/c data buses)
• Civil Standards - FAR 25 : 1309 A (equipments, systems and
installation), FAR 25 : 581 (lightning protection systems), FAR 25 : 571
(control systems), FAR 25: 572 (stability augmentation systems)
62. Give few examples of integrated avionics system used in civil airlines.
• INS & GPS (Navigation)
• MFKs and MFDU (Display I/O)
• HUD
• Glass Cockpit
63. Explain the steps of certification.
• Assessment
• Validation
• Verification
Other major steps like
• Functional Hazard Assessment (FHA)
• Fault Tree Analysis (FTA)
• Failure Mode Effect Analysis (FMEA)
64. Explain the document support for Certification.
• In Military aircrafts, the documents support for certification
i. MIL-STD-1629A (Hardware)
ii. DOD-STD-2167 (Software)
• In Civil aircrafts, the document support for certification
o FAR 25 : 1309A (systems)
o RTCA-DO-178A (Software)
Within the overall task of hardware assessment and validation,
certification is perhaps the most difficult part for civil/military avionics designers. Certification is the challenging process of negotiation and
compromise between the designers and the regulatory authorities
buttressed by technical analysis and expertise on both sides.
65. Explain the advantage of GPS over conventional navigation.
• Global coverage and assessment
• More precise
• High integrity and portable simple system
• Augments the accuracy of the self contained systems
66. Explain FBW over FBL.
• FBW: (FLY BY WIRE) It’s a concept of utilizing digital data bus for the
transmission of mechanical movements from pilot’s joystick to the
Mechanical actuators near by the control surface in the form of electronic
signals using suitable transducers. It eliminates majority of the weight in
handling control rods, push pull systems. Because of this weight
elimination the redundancy level of FBW can be raised.
• FBL: (FLY BY LIGHT) It’s a concept of utilizing optic fiber cables for
the transmission of mechanical movements from pilot’s joystick to the
mechanical actuators near by the  control surface in the form of
monochromatic light signals using suitable transducers. It eliminates the
amplification units, filter circuits, modulator units etc., which are at high
redundant levels in the FBW. FBL is more reliable and the signals passing
through the fiber optic cable never degrade and hence it contributes further
low weight in the aircraft.
 
67. What is FBL?
• FBL: (FLY BY LIGHT) It’s a concept of utilizing optic fiber cables for
the transmission of mechanical movements from pilot’s joystick to the
mechanical actuators near by the  control surface in the form of
monochromatic light signals using suitable transducers. It eliminates the
amplification units, filter circuits, modulator units etc., which are at high
redundant levels in the FBW. FBL is more reliable and the signals passing
through the fiber optic cable never degrade and hence it contributes further
low weight in the aircraft.
68. Compare INS and GPS.
Sl.
No.
INS GPS
01 Self contained system Not a self contained system 02 Accuracy degrades with time
Accuracy level is high
always
03
Being a self contained system, weight is
more
Weight is less
comparatively
04 No signal transmission/reception
Signal is
transmitted/received
69. What is usage of night vision goggles?
• Night time flight is possible (As pilot can see the terrain like a near
morning)
• Close Ground Support during night time attack is enabled in rotor and
fighter planes
• Night time reconnaissance and surveillance is possible on NVG enabled
cameras
70. Explain advantage of EL over Plasma display.
• Less flickering
• Sustainable luminosity even during aging
• Light weight than plasma displays
• Simple light weight component
• Available in smaller size (unlike plasma displays, which are available only
at 32”)
71. Explain the need of communication system in airline.
• Renders a clear picture of aircrafts health during the complete mission
• Ensures safety landing and take-off guidance
• Provides suitable environment awareness to the crew members of flight to
direct the flying machine
• Acts as primary interfacing unit between pilot and the ATC or ground
station.
72. Explain the advantage of HMD over MUD?
• 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.  73. Explain MFK and its usage.
• As the cockpits of modern aircraft have more controls jammed into them,
the point reached where there is no more space. Multifunction keyboards
(MFKs) offer a very attractive solution to this space problem wherein a
single panel of switches performs a variety of functions depending on the
phase of the mission or the keyboard menu selected.
• Multifunction keyboards can be implemented in several ways. The first
two ways use LEDs or LCDs in panels in a central location. Designs using
LEDs have arrays (typically ranging from five rows of three switches to
seven rows of five switches) of standard sized push button switches with
legends built into the surface of the switches.
74. Differentiate between Civil and military communication standards.
Sl.
No.
Civil Communication
Standards
Military Communication Standards
01
Speed level in data bus is
generally slow
Speed level in the data bus is high
02
Frequency band is in
common range of
communication devices
Frequency band is in isolated or restricted
range of communication devices. It varies
between nation to nation
03
Redundancy and integrity
level is moderate
Redundancy and integrity level is high
04
Maintenance is spoken in
terms of Cost Of Ownership
(COO)
Maintenance is spoken in terms of Life
Cycle Cost (LCC)
05
Ex: ARINC 429, FAR-25-
1309A
Ex: MIL-STD-1553A, MIL-STD-16629A
75. Differentiate between ARINC 429 and ARINC 629.
Sl.
No.
MIL-STD-1553A ARINC 429 ARINC 629
01 Adopted in 1970
Adopted in
1977
Adopted in 1989
02 Half duplex data bus
Simplex data
bus
Duplex data bus
03
SPEED
1 Mb/s
SPEED
Critical data
100 Kb/s
Non critical
data 12-14.5
Kb/s
SPEED 2 Mb/s
04
Command/Response
protocol
Williamsberg
protocol
Protocol: CSMA/CA – Carrier
sense multiple access/ Collision
avoidance 05
Called as Digital Time
Division
Command/Response
Multiplex Data bus
Called as
Digital Data
Compendium
Called as DATAC- Digital
Autonomous Terminal Access
Control
06  31 RTs can be accessed
 
- -
76. Explain the major components of microprocessor.
• Arithmetic and Logical Unit
• Timing and Control Unit
• Register sets
77. What is fetching?
• Fetching means getting/bringing/taking/carrying/obtaining the
value/address from the specific memory location/register pair.
• Assembly language code MOV B,A says that fetch the 8 bit data from
accumulator to B register.
78. Give the need for standard documents in the design of avionics system.
• In most of the aircrafts, the most  important avionics  function is flight
controls, frequently in flight critical manner, that is, if the avionics fail, the
aircraft is lost. Because of the critical role for the avionics, it is essential to
take early surveys to formulate standards.
• Those standards must ensure the aircraft safety even during the critical
failure of its avionics components.
• Those accepted standards have to be documented so that in future avionics
design for various aircraft it would be considered as reference to build it.
• Ex. MIL-STD-9490, 1629, 810 etc.,
79. Give the advantages of digitization.
• Digitizing or digitization means converting the analogue data in to discrete
or digital data source.
• Converting the details about a picture/sound/scene in to a discrete form is
called as digitizing.
80. 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
81. Explain the usage of microprocessors in Avionics system.
• In ground station, the complete avionics on ATC (AIR TRAFFIC
CONTROL) is running on the backbone of microprocessor for various
data computation. (weather data computation)
• Sensors on the airborne equipments  are interrupted and computed to the
understandable values and displayed on the panels only through the use of
microprocessor. (Temperature monitoring system)
• And most of the avionics system in fighter planes utilizes microprocessor
for data computation and presentation. (HMT, HUD)
82. How are reliability and maintainability related to each other?
• When a system is said to be more  reliable and maintainable then it is
readily available.
• A more reliable system requires less maintenance and a less reliable
system requires more maintenance. Hence a suitable trade-off has to be
made between these two things to save money.
• Both increase in reliability and maintainability requires more money in
turn.
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