Here is the 4th article of the exclusive AAI ATC Interview Series which primarily focuses on the preparation of the JE (ATC) Interview. The series is consisted of Five Articles which cover non-technical as well technical questions that I suppose can be asked in the ATC interview.
- Read First Article of AAI ATC Interview Series (Questions 1 to 26)
- Read 2nd article of AAI ATC Interview Series (Questions 27 to 38 )
- Read 3rd article of AAI ATC Interview Series (Questions 39 to 45)
- Read Last article of AAI ATC Interview Series (Questions 53 to 65)
This article covers topics such as how does aircraft fly, axis of aircraft, important parts of an aircraft along with the trivial questions like type of fuel used in Aircraft. As per me an ATC aspirant must be aware of the machine (read as Aircraft) that he/she is going to guide and control, after getting inducted in AAI.
Ques. 46: In which layer do aircraft prefer to fly and why? Ans.Generally commercial airliners fly in stratosphere or tropopause region which lies at altitudes of 9–12 km (30,000–39,000 ft).This region is clear of bad weather and has small amount of clouds as compared to troposphere. In other words, stratosphere does not have turbulence, so the aircraft can fly more smoothly. It enables the aircraft to save fuel.
Ques. 47: What type of fuel is used in aircraft? Ans.The fuel used (in aircraft with gas turbine engines) is called Aviation Turbine Fuel (ATF) or Jet Fuel, which is generally very pure, has anti-knock additives and has very high calorific values.2 Widely used ATFs are unleaded Kerosene(Jet A-1, it is used by most of commercial airlines in the world) or Naphtha kerosene blend (Jet B). Other type of fuel used (by Aircraft with internal combustion engines) is AvGas (Aviation gasoline) which is Petroleum based fuel.
Ques. 48: What are various forces on Aircraft? Ans.There are four forces that act on an aircraft at any given point of time. The forces are:
Lift: provided by wings (Bernoulli’s Principle), Thrust: provided by Engine(s)
Ques. 49: How does aircraft fly? Ans. First understand how lift is produced: The wings of aircraft have a curved upper surface whereas lower surface is flatter. This cross-sectional formation is called Aerofoil. When air rushes over the curved upper wing surface, it has to travel further and go slightly faster than the air that passes underneath. Now Bernoulli’s Principle comes in to the picture as fast-moving air is at lower pressure than slow-moving air, so the pressure above the wing is lower than the pressure below; creating the lift that holds the plane up. So this aerofoil shape of wings is behind the lift of the aircraft. (This concept has been well described in NCERT Physics Book) Now let’s understand one more important thing i.e. Angle of attack. According to Newton’s Third Law of Motion if air produces an upward force, then aircraft must also produce an equal and opposite downward force. But how do wings push the air downward behind it?? It is possible only when wings are tilted back slightly so they hit the air at an angle of attack. With the increase in angle of attack, the lift also increases (up to a point), further increase in the value of Angle of attack will cause aircraft to stall. Condition for Aircraft to fly horizontally:
When Lift = Weight AND Thrust > Drag.
Ques. 50: What are various axes of Aircraft? Ans.There are three axis viz.
- Roll (Longitudinal axis)
- Pitch (Lateral axis)
- Yaw (Vertical axis)
Ques. 51: What are important parts that control the movement of Aircraft in the air? Ans.Although every part of an aircraft plays a role in the operation of the aircraft and that is why these parts are required to be mounted on the fuselage; however these three parts are very crucial for the movement of the aircraft along the three axes (Pitch, Roll and Yaw).
- Rudder: Allows aircraft to move about Yaw axis i.e. Aircraft will turn left or right with the movement of the Rudder.
- Elevator: As the name suggests, Elevator is used to move the aircraft along the Pitch axis i.e. Aircraft will move up or down with elevator’s movement.
- Aileron: Aileron allows the aircraft to rotate i.e. movement of aircraft along the Roll axis.
Additionally, when the aircraft is moving slower, Flaps are used to produce extra lift at take-off and extra drag at landing.
Ques. 52: What is Solar Aircraft? Which solar aircraft was in news in last year (2015)? Ans. Solar plane is an aircraft that is powered by solar energy. The aircraft that was in news in Solar Impulse (Si2), a single-seater aircraft which is capable of flying day and night by harnessing the solar energy. It a next generation aircraft which is on Round-the-world flight and started its 35000 kms journey on March 9, 2015 from Abu Dhabi (UAE). In India, it first landed in Ahmedabad and then Varanasi before leaving for Myanmar. The mission of this flight is: ‘Around the world to promote clean technologies.’
Edit: Read latest post about important definitions and terms like ADS-B, SSR, SBAS, GBAS, Runway, Flight Level etc for ATC Interview Preparation. Link is:
Important Terms and Definitions for JE-ATC Interview
If you find this article interesting and useful, please share it on your social networks.