This set of Avionics Multiple Choice Questions & Answers (MCQs) focuses on “Data Bus Systems”.
1. Which of the following is false with respect to AIRNIC?
a) Define system and equipment specification
b) Non-profit organization
c) Run by civil airlines with industry and establishment representation
d) Used only in America
Explanation: ARINC is a non-profit-making organization in the USA which is run by the civil airlines with industry and establishment representation, which defines systems and equipment specifications in terms of functional requirements, performance and accuracy, input and output interfaces, environmental requirements and physical dimensions and electrical interfaces. For example, air data computers, attitude heading reference systems, INS, communication radio equipment, data bus systems, etc. Although it is a US based company the system standard is worldwide.
2. What is the fastest mode of data communication between components in aircraft?
a) Coaxial cable
b) Twisted pair cable
c) Fiber optic cable
d) Radio communication
Explanation: A single screened twisted pair of wires only is required with such an encoding system to transmit information data rates of up to 1 to 2 Mbits/s. Higher data rates of up to 100 Mbits/s can be transmitted using a suitably screened coaxial electrical cable and information at even higher data rates can be transmitted as coded light pulses using a fibre optic cable. Radio communication is not for data transfer between aircraft components.
3. In an aircraft, serial data transfer is achieved by _________
a) Time division Multiplexing
b) Code Division Multiplexing
c) Frequency Division Multiplexing
d) Pulse Modulation
Explanation: The individual avionic sub-systems are interconnected by means of a digital data bus system. This enables the system to communicate with each other and transfer serial data information using time division multiplexing.
4. What type of avionic architecture consist of a number of an interconnected but functionally independent subsystem with some degree of central computer of overall operating modes.
a) IMA architecture
b) Federated architecture
c) Disjoint architecture
d) Distributed architecture
Explanation: Federated architectures essentially consist of a number of interconnected but functionally independent sub-systems with some degree of central computer control of overall operating modes. System is loosely coupled and are connected via a time shared multiplex highway.
5. How are Data bus in avionics architecture broadly divided into?
a) High speed and low speed data bus
b) AIRNIC and MIL standard data bus
c) Electrical and Optical data bus
d) Main and interconnecting data bus
Explanation: Data bus systems are the essential enabling technologies of avionic systems integration in both federated and integrated modular avionics architectures. They can be broadly divided into electrical data bus systems where the data are transmitted as electrical pulses by wires, and optical data bus systems where the data are transmitted as light pulses by optical fibres.
6. The type of Ethernet data bus adapted for airborne applications is _______
a) Airborne Simplex Ethernet
b) Airborne Duplex Ethernet
c) Multiplexed Ethernet
d) Avionics Full Duplex Switched Ethernet
Explanation: The version which has been adapted for airborne applications is known as the ‘Avionics Full Duplex Switched Ethernet’, which has been shortened to ‘AFDX Ethernet’ network. It meets the civil aircraft avionic system requirements in all aspects and its commercially sourced components make it a very competitive system.
7. What type of cable does MIL STD 1553 use?
a) Coaxial cable
b) Single twisted pair cable with shielding
c) Single twisted pair cable without shielding
d) Fiber optic cable
Explanation: The MIL STD 1533 bus is formed as a single twisted cable pair with one layer of shielding and jacketing and with a maximum length of 100 m (328 ft). Although direct coupling to the bus is allowed, this is generally not used in order to avoid the risk of one terminal shorting out the bus. The bus connection is typically via a transformer coupled stub so that shorting of the stub is isolated from the bus.
8. What property does data transmission in fiber optic cable exploit?
b) Total internal reflection
Explanation: The transmission of light signals along any optical fibre depends on the optical property of total internal reflection. The transmitted light pulses get reflected by the cladding in the fiber cable at the same time move in the forward direction. One main disadvantage of fiber optic cable is that it cannot be easily bent.
9. Which one of the following is the major difference between single mode and multi mode fibers?
a) Core material
b) Cladding material
c) Core diameter
d) Cladding diameter
Explanation: The major difference between single mode fibre and multi-mode fibre is that the core diameter of single mode fibre is of the same order of magnitude as the wavelength of the light source (laser diode). Pulse dispersion is reduced in single mode fiber.
10. Avionics Full Duplex Switched Ethernet provides flexibility to manage any change in the data communication between the connected systems without wiring modifications.
Explanation: The network provides 100 Mbits/s full duplex (two way) communication and provides flexibility to manage any change in the data communication between the connected systems without wiring modifications.
Sanfoundry Global Education & Learning Series – Avionics.
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