Engineering Questions with Answers - Multiple Choice Questions

MCQs on Head Down Display Technology

1 - Question

What are the four electromechanical devices retained while making an avionics update for old aircraft?
a) Vertical speed indicator, airspeed indicator, artificial horizon and heading indicator
b) Altimeter, airspeed indicator, artificial horizon and angle of attack indicator
c) Altimeter, airspeed indicator, turns coordinator and heading indicator
d) Altimeter, airspeed indicator, artificial horizon and heading indicator

View Answer

d
Explanation: Avionics update is one of the effective ways to extend the life of an aircraft. The technology is undergoing an exponential growth and is hence viable to use multifunctional CRT displays in places of mechanical dials. However, the basic T instruments, the altimeter, airspeed indicator, artificial horizon and heading indicator are retained because of their importance in flight control. In modern cockpits, even these are being replaced by solid-state devices with LCD display.




2 - Question

OLED display is better than LED because ________
a) They are cheaper
b) They have high brightness
c) Do not require any illuminating source
d) Easy to manufacture

View Answer

c
Explanation: OLED displays have numerous advantages over the LED display in the aviation industry. They have a high resolution and are super thin flat panel which can even be curved. It is an emissive display and thus do not require any backlighting. This obviously reduces weight and is optimal for the aviation industry.




3 - Question

What are the 5 primary mechanical displays, a Primary Flight Display (PFD) can replace?
a) Altimeter, turn coordinator, vertical speed indicator, artificial horizon and heading/compass indicator
b) Altimeter, vertical speed indicator, artificial horizon, heading/compass indicator and Mach meter
c) Altimeter, vertical speed indicator, artificial horizon, heading/compass indicator and landing gear position
d) Altimeter, turn coordinator, artificial horizon, heading/compass indicator and Mach meter

View Answer

b
Explanation: The instruments that are replaced by the PFD are the basic instruments necessary to fly an aircraft. These instruments are altimeter, vertical speed indicator, artificial horizon, heading/compass indicator and Mach meter. All the primary information is shown in the PFD so that the pilot does not have to scan for information.




4 - Question

Why are mechanical instruments retained when high tech LED displays are available?
a) LED displays are costly
b) LED Displays cannot withstand the flight environment conditions
c) Probability of failure
d) Accuracy

View Answer

c
Explanation: Although high tech LED Displays are available the mechanical systems are still used as a fail-safe for the LED display. There is always a chance of electrical failure due to engine failure and power supply may be cut off. In situations like this mechanical systems are necessary to land the plane safely.




5 - Question

Which of the following is false with respect to multi-function LCD displays in cockpits?
a) High resolution
b) More information to be displayed
c) Bigger and customizable display
d) Take more space in cockpits

View Answer

d
Explanation: In a typical fighter aircraft there are hundreds of flight parameters and focus cannot be given to all of them. In a dial gauge cockpit, the pilot has to keep track of all the parameters by looking into various gauges which are quite confusing and arises a lot of man-made error. To overcome this problem LED/LCD displays are used which are bigger in size for the same weight and customizable. They also take up a lesser place in the cockpit as they are super thin and flat.




6 - Question

How many Primary Flight Displays are present in typical civil aircraft cockpit?
a) 1
b) 2
c) 4
d) 3

View Answer

b
Explanation: A typical civil aircraft cockpit will have 4 displays, 2 Primary Flight Displays, and 2 Multi-Functional Displays. The 2 PFDs are duplicated (i.e; they display the exact same information) one for the pilot and one for the co-pilot. The other two displays can be chosen what to show either by the pilot or the copilot.




7 - Question

Which one of the following is false with respect to electromechanical instruments?
a) High cost
b) Require skilled labor for repair
c) Accurate measurements
d) Inevitable wear

View Answer

c
Explanation: Although electromechanical instruments have been used for a long period of time, the cost of ownership of such instrument is high. These also depend on very low friction precision mechanisms which require skilled labor for repair. Since they have rotating components in them they have inevitable wear and deterioration in the spin axis bearing system. Due to this, their measurements may not be accurate with time.




8 - Question

What are the standby instruments that are combined in a Solid state integrated standby instrument?
a) Altimeter, vertical speed indicator, artificial horizon
b) Altimeter, airspeed indicator
c) Altimeter, airspeed indicator, artificial horizon
d) Altimeter, turn coordinator, artificial horizon, heading/compass indicator and Mach meter

View Answer

c
Explanation: The standby attitude indicator, standby altimeter, and standby airspeed indicator are replaced with a single solid-state integrated standby instrument system packaged in a 3 ATI case. They consist of solid-state gyros and accelerometers, solid-state pressure sensors along with a microprocessor and color AMLCD.




9 - Question

What is the operating voltage of Solid-state integrated standby instrument?
a) 11V DC
b) 28V DC
c) 5V DC
d) 115V DC

View Answer

b
Explanation: The Solid-state integrated standby instrument operates from the 28V DC supply produced by the emergency batteries. The integral power conditioning electronics are designed to cope with the variations in the battery supply voltage.




10 - Question

The solid-state instruments are of higher accuracy than mechanical systems.
a) True
b) False

View Answer

a
Explanation: The instruments are of higher accuracy because of the use of solid-state sensors and the ability to apply complex corrections using the embedded microprocessor. Electro-mechanical instruments are limited in the complexity of the corrections which can be made.

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