Important Terms and Definitions for JE-ATC Interview

In this article, which is aimed at preparing for JE-ATC Interview, I will first give some basic definitions that you must know before appearing in the ATC Interview. These are general terms ATC guys encounter in day-to-day business like what is Aircraft? What is a Runway or Taxiway? How do they define Flight levels in the sky?

Once this definition part is done then I will focus on Communication, Navigation, and Surveillance Systems that are very essential for the safe conduct of flight in all phases of a flight. These systems make it possible to monitor and guide so many aircraft in the sky or ground at any given time.


Aerodrome: In aviation, an airport is usually called an Aerodrome. It is a defined area on land or water (including any buildings, installations, and equipment) intended to be used either wholly or in part for the arrival, departure, and surface movement of aircraft.

Aircraft: Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface.

Runway: A defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft.

Taxiway: A defined path on a land aerodrome established for the taxiing of aircraft and intended to provide a link between one part of the aerodrome and another.

Elevation: The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level.

Flight Level: A surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hecto-pascals (hPa), and is separated from other such surfaces by specific pressure intervals.

Track. The projection on the earth’s surface of the path of an aircraft, the direction of which path at any point is usually expressed in degrees from North (true, magnetic, or grid)

Communication, Navigation, and Surveillance Systems used in ATC:

Radar: A radio detection device that provides information on the range, azimuth, and/or elevation of objects.

Primary Surveillance Radar (PSR): A surveillance radar system that uses reflected radio signals.

Secondary Radar: A radar system wherein a radio signal transmitted from the radar station initiates the transmission of a radio signal from another station.

Secondary Surveillance Radar (SSR): SSR is a surveillance radar system that uses transmitters/receivers (interrogators) and transponders.

CPDLC: The CPDLC (Controller-Pilot Data Link Communication) application provides a means of communication between the controller and pilot, using data links for ATC communication.

VOR: VHF Omni Directional Radio Range (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons.

ILS: Instrument Landing System (ILS) enables aircraft to land if the pilots are unable to establish visual contact with the runway. It does this by way of transmitted radio signals.

Localizer: The Localizer is used to provide horizontal guidance to the Pilot. It indicates how far off its optimal path of descent is along the axis of the runway.

Glide Slope: It provides vertical guidance to the Pilot. The glide slope indicator ensures that the aircraft is following the glide path to remain above obstructions and reach the runway at the proper touchdown point.

DME: Distance Measuring Equipment (DME) is a transponder-based radio navigation technology that provides pilots with a slant range measurement of the distance to the runway in nautical miles.

Marker Beacon: A marker beacon is a particular type of VHF radio beacon used in aviation, usually in conjunction with an instrument landing system(ILS), to give pilots a means to determine position along an established route to a destination such as a runway.
a) Outer marker: The Outer Marker is situated on the same course/track as the localizer and the runway center-line, four to seven nautical miles before the runway threshold.
b) Middle marker: A middle marker works on the same principle as an outer marker. It is normally positioned 0.5 to 0.8 nautical miles (1 km) before the runway threshold.
c) Inner marker: Similar to the outer and middle markers; located at the beginning (threshold) of the runway on some ILS approach systems.

GNSS: A satellite navigation system with global coverage may be termed a global navigation satellite system (GNSS). GNSS is used to pinpoint the geographic location of a user’s receiver anywhere in the world.

GBAS: Ground-Based Augmentation System (GBAS) is a safety-critical system that augments the GNSS Standard Positioning Service (SPS) by differential corrections and integrity monitoring and provides enhanced levels of service.

SBAS: Satellite-Based augmentation system (SBAS) is a system that supports wide-area or regional augmentation through the use of additional satellite-broadcast messages.

GPS: Global Positioning System (GPS) is a space-based navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.

ADS-B: Automatic Dependent Surveillance-Broadcast (ADS–B) is a cooperative surveillance technology in which an aircraft determines its position via satellite navigation. The information can be received by air traffic control ground stations as a replacement for secondary radar. It can also be received by other aircraft to provide situational awareness and allow self-separation. ADS–B is “automatic” in that it requires no pilot or external input. It is “dependent” in that it depends on data from the aircraft’s navigation system.

ACAS: Airborne Collision Avoidance System (ACAS) is also known as TCAS (Traffic Collision Avoidance System). TCAS/ACAS is an aircraft system that works on the basis of Secondary Surveillance Radar (SSR) transponder signals that work independently of ground-based equipment. It provides advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders.

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Reference: ICAO DOC 4444.

Also Read – How To Prepare For ATC Exam


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58 thoughts on “Important Terms and Definitions for JE-ATC Interview”

  1. Sir,
    there is a new list of qualified candidates called for interview for the post of atc. So are the interview of the candidates that took place under phase 1 still valid ?

  2. Sir.. I m very sad due to.. The attitude of aai towards candidates.. Ist they called for interview.. N now cancelled and withdraw the schedule for interview.. Ist they should prepare merit.. Then should call for interview… Y they r playing with the future of candidates.. God knows..

    1. I agree that it is not the right way for recruitment. They should have proper preparation before uploading anything on website. But They are not playing with your future dear…just some unwanted delay.

      1. pragati aggarwal

        aai has shortlisted 1810 candidates for 2nd phase interview which will end on 20th june, so when should we expect the result sir??

  3. Sir,
    My name is in the second interview list which was uploaded by AAI on 29th April 2016. My interview date is 17th June 2016. Sir, it appears that i am just at the cutoff if the list was prepared on the merit basis. Then sir, i want to ask you what are my chances of selection after interview?

  4. Mrityunjay Boro

    Sir, I got the call letter(interview and voice testt) 2nd phase. My concern is that previously in 3/2015 advt. the graduates only from IT/ECE or in engg disciples are selected. My application status states B.Tech in IT but I am graduate in CSE. But now the elligiblity criteria Includes every graduates in B.Tech disciples. Will i get disqualified in interview?

  5. Sir, Can you please upload the interview experience of the candidates those have already appeared in Phase-I.

    1. sudhir sheoran

      i have uploaded the questions. that is what you must be interested in. Anything else you need to know regarding interview?

  6. Hello Sir ,

    I am working in TCS . Do i need to produce NOC ?

    Please see below
    Candidates employed in Govt. Departments/PSUs/Autonomous bodies must produce No Objection Certificate (NOC) at the time of interview from their employer. In case, the candidate fails to produce the NOC, his/her candidature will not be considered.

    I am not getting the meaning of Autonomous body .

    Please help.

  7. Sir,
    Can you please let me know the whole day schedule of the interview if they start at 9.00 am onwards.

    1. sudhir sheoran

      If you start by 9 then first doc verification by 1000. Then voice test by 1100. Interview by 1300.

  8. Thank you very much Sir..!!

    I got selected for interview in the second list of 3/2015 notification.

    Can you please suggest, what would be the best answer for “Why do you want to join ATC, why not IES, other PSUs? “

    1. sudhir sheoran

      Just show them your enthusiasm for ATC, Aviation, uniqueness of this profession, respect an ATC officer gets at airports and in society.

  9. Sir..during interview if they ask ” why should we select u ?”
    What should be the impressive answer ??
    Sir,,More frankly , what will u answer if you are facing the interview ??

    1. sudhir sheoran

      Hehe…everyone has own strengths and qualities which makes him/her suitable for a certain kind of job. You need to find it yourself dear. I cant tell you why should they hire you.

    2. sudhir sheoran

      Hi Sourav…plz share your interview experience with us so that we can improve content on incomopedia to help other guys who are preparing for it.

  10. sir
    i am belong form obc ncl student , but do not have a in format of central job farmat
    i have a obc certficed in format of state gov. sir during interview , i am allow or not for interview

    1. sudhir sheoran

      Without obc certificate you won’t be allowed. Why did you applied in obc category when you didn’t have certificate?

  11. Sir,I hv got selected for the interview but my english is little weak. I hv frusted that how will I perform there.sir pls suggest me..

    1. sudhir sheoran

      Just express yourself in Hindi or English whatever medium you are comfortable. It is also mentioned in the interview letter as well that candidate can answer in Hindi or English. Prepare well and give your best. Good luck. Share your experience and questions on incomopedia.

  12. Sir….what is the cut off of sc category for 2nd list atc interview….is it less from nprevious one….or same?….

    1. sudhir sheoran

      There is no separate cut off for interview round. Total marks of written and interview will be counted to prepare cut off.

      1. Ok….sir….i mean written cut of for 1st list sc category was 68.17… my question…. is this written mark cut off is same for 2nd list candidate or less?…on what basis they are calling for 2nd list candidate…..please inform me sir…..

  13. Sir….please infirm me whether ATC written exam cut off of sc catgory for 2nd list candidate is same with 1st list candidate or not?…

  14. Sir.. Today I withdraw my case regarding junior executive atc advt no 03/2015 exam held on 26 /12 /2015. I filed a writ petition in Delhi high Court regarding error in keys. Now I called for interview and my interview was on 20th may. I would like to thank you sir for ur guidance. All the questions asked in interview were from ur blog. Now waiting for result and sure I will got selection. May God bless u.. And may God bless

  15. Sir.. I m little tense. Pls help me. I filed a writ petition in Delhi high Court regarding error in the key in advt no. 03/2015 for junior executive atc. After my writ petition they revised the key n called me for interview. My interview is on 20 th may. I m worried that there is any negative impact on my result due to filing writ petition. Some people r saying that they will take revenge. Pls help me sir..

  16. Sir, all the comments and posts here are for the advertisement 3/2015. Anything new that you want to add for the 7/2015 interview? My interview is on 10th of march. Actually if I can get some experiences of the candidates, that would be really of a huge help.

  17. You will be reimbursed AC III Tier Train fare or actual Bus fare by shortest route on submission of self attestedcopy of proof of
    travel,provided the distance travelled by Rail/Bus each way exceeds 80 Kms.

    I am having above information in my interview call letter,my correspondence address is differ from permanent address which takes more travel time.So,which address i need to choose ?.

  18. hello sir, i m a graduate major in chemistry…i m being selected for the JE ATC interview…i hve studied physics and maths subject for 2-2 semesters each and in advt it was just mentioned graduate from with physics and maths…am i gonna face any problem during interview??

    1. sudhir sheoran

      In my opinion you don’t have required qualifications as Maths and Physics should have been studied in all the 6 semesters/3 years.

  19. sir,
    i have been call for the interview against 7/2015 advertisement. in the call letter it is mentioned to bring admit card… but i have lost it…. what should i do…???? please help…!!!!!

    1. Take a printout of Whatever you have like application form/interview call letter and all AAI emails you have got and appear there. They will allow you. Just convince them in case needed.

  20. i have been called for the interview against 7/2015 advertisement. i am b-tech in electrical enginering . can i attend the interview

    1. sudhir sheoran

      Didn’t you check your eligibility before applying for this post? All btech branches are eligible .

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