Important Questions For AAI ATC Interview | Article 4/5

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 consists of Five Articles that 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 aircraft fly, the axis of aircraft, and important parts of an aircraft along with trivial questions like the 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 into AAI.

Ques. 46: In which layer do aircraft prefer to fly and why?

Ans. Generally, commercial airliners fly in the 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 a small number of clouds as compared to the troposphere. In other words, the 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, which is used by most of the commercial airlines in the world) or Naphtha kerosene blend (Jet B). Another 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 in time. The forces are:

• Lift
• Thrust
• Drag

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 the 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 into the picture as fast-moving air is at a 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 them? It is possible only when wings are tilted back slightly so they hit the air at an angle of attack. With the increase in the angle of attack, the lift also increases (up to a point), further increase in the value of the 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 is a 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).

1. Rudder: This allows aircraft to move about the Yaw axis i.e. Aircraft will turn left or right with the movement of the Rudder.
2. 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 the elevator’s movement.
3. 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 2015?

Ans. A solar plane is an aircraft that is powered by solar energy. The aircraft that was in news in Solar Impulse (Si2), is a single-seater aircraft that is capable of flying day and night by harnessing solar energy. It is a next-generation aircraft that is on a Round-the-world flight and started its 35000 km 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.’

• Read Questions 1 to 26
• Read Questions 27 to 38
• Read Questions 39 to 45
• Read Questions 53 to 65

Edit: Read the 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

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