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DGCA Air Regulations · 160 questions

Air Traffic Services: DGCA Air Regulations Questions and Answers

160 practice questions on Air Traffic Services with answers and explanations, plus the key concepts and formulas, from the TrueHeading question bank.

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About this topic

Use this page to revise Air Traffic Services for the DGCA Air Regulations paper. Below are the key ideas first, then 12 practice questions with answers and explanations, picked from the 160 questions in the TrueHeading bank for this topic.

In short: ICAO Annex 11 classes:

Open the full set in the student zone to answer every question, track your accuracy and take timed mock tests.

Key concepts: Air Traffic Services

9 ideas to know cold.

What does each airspace class provide?

ICAO Annex 11 classes:

  • A: IFR only, all separated, clearance required
  • B: IFR and VFR, all separated
  • C: IFR separated from all; VFR from IFR only
  • D: IFR from IFR; VFR gets traffic information
  • E: IFR from IFR; VFR not separated
  • F: advisory (IFR), information (VFR) · G: flight information only

Speed limits and RVSM?

Below FL 100, 250 kt IAS in Classes C, D, E, F and G.

  • RVSM: 1000 ft separation between FL 290 and FL 410 for approved aircraft and operators
  • Outside RVSM above FL 290: 2000 ft

Radar separation minima (ICAO)?

Horizontal: 5 NM en route, 3 NM where surveillance allows near aerodromes. Vertical: 1000 ft below FL 290.

  • Wake turbulence by radar: heavy behind heavy 4 NM, medium behind heavy 5 NM, light behind heavy 6 NM, light behind medium 5 NM

How is a holding pattern flown and entered?

Standard pattern: right-hand turns, 1 minute legs up to 14 000 ft (1½ minutes above).

  • Entries: direct, parallel or teardrop, decided by the 70° line
  • Turn at Rate 1 (3°/s) or 25° bank, whichever needs the lower bank
  • Maximum speeds: 230 kt to 14 000 ft, 240 kt to 20 000 ft, 265 kt to 34 000 ft, Mach 0.83 above

Primary and secondary radar?

Primary radar listens for the pulse bounced off the aircraft. Secondary radar asks a transponder to reply.

R=c Δt2R=\frac{c\,\Delta t}{2}
  • SSR interrogates on 1030 MHz and replies on 1090 MHz
  • Mode A: identity code (4096 codes) · Mode C: pressure altitude · Mode S: selective addressing, enables ADS-B and TCAS
  • PSR needs no cooperation, so it sees non-transponder aircraft and weather
PSR: echoreflected pulse onlySSR interrogation 1030 MHzreply 1090 MHz: code + altitudeno cooperation neededtransponder needed

Radiotelephony words you must use right?

Standard phraseology:

  • Roger: received your last transmission
  • Wilco: will comply
  • Affirm / Negative: yes / no
  • Say again: repeat; never “repeat”
  • Standby: wait; I will call you
  • Readback required for clearances and runway instructions
  • Readability scale 1 (unreadable) to 5 (perfectly readable)

FIRs in India?

Four flight information regions: Delhi (VIDF), Mumbai (VABF), Kolkata (VECF) and Chennai (VOMF).

Tip: The ICAO prefix for India is VA, VE, VI and VO.

Explain the airspace classes A to G.

A: IFR only, all controlled. B: IFR/VFR, all separated. C: IFR/VFR, VFR separated from IFR. D: IFR/VFR, IFR separated from IFR. E: IFR/VFR, IFR separated from IFR. F: advisory. G: uncontrolled.

  • A–E controlled; F, G uncontrolled
  • VFR not permitted in Class A
  • Clearance required for IFR in A–E and for VFR in B–D

What are the ICAO SSR codes for emergencies?

7700 general emergency, 7600 radio failure, 7500 unlawful interference (hijack).

  • Mode A: 4096 codes (octal)
  • Mode C: pressure altitude in 100-ft increments
  • Mode S: selective address and data link

Practice questions: Air Traffic Services

Tap “Show answer” after you have tried each one.

Q1The objectives of air traffic services include all of the following EXCEPT:

  1. regulating airline fares
  2. notifying organisations of aircraft needing search and rescue
  3. preventing collisions between aircraft
  4. providing advice and information for safe and efficient flights
Show answer

Answer: A. regulating airline fares

Annex 11 objectives: prevent collisions, expedite and maintain an orderly flow of traffic, provide advice and information, and alerting service.

Q2Class A airspace permits:

  1. IFR flights only, all of which are subject to ATC clearance and are separated from each other
  2. VFR flights only
  3. IFR and VFR flights
  4. IFR flights with no ATC service
Show answer

Answer: A. IFR flights only, all of which are subject to ATC clearance and are separated from each other

VFR flights are not permitted in Class A airspace.

Q3The vertical separation minimum below FL 290 is:

  1. 1 000 ft (300 m)
  2. 2 000 ft
  3. 3 000 ft
  4. 500 ft
Show answer

Answer: A. 1 000 ft (300 m)

Above FL 290 the minimum is 2 000 ft, unless RVSM is applied (1 000 ft between FL 290 and FL 410).

Q4Read-back of ATC clearances is required for:

  1. all transmissions
  2. route clearances, level instructions, headings, speeds, runway, altimeter settings and SSR codes
  3. only weather information
  4. none of them
Show answer

Answer: B. route clearances, level instructions, headings, speeds, runway, altimeter settings and SSR codes

Annex 10 requires read-back of safety-related items.

Q5The "alert phase" in the alerting service is called:

  1. ALERFA
  2. DETRESFA
  3. SARFA
  4. INCERFA
Show answer

Answer: A. ALERFA

INCERFA = uncertainty phase; ALERFA = alert phase; DETRESFA = distress phase.

Q6In radiotelephony, the digit 9 is pronounced:

  1. NYNE
  2. NINE
  3. NINER
  4. NIN-ER (but spelt)
Show answer

Answer: C. NINER

Numbers: 0 ZE-RO, 1 WUN, 2 TOO, 3 TREE, 4 FOW-ER, 5 FIFE, 6 SIX, 7 SEV-EN, 8 AIT, 9 NIN-ER.

Q7The standard word meaning "yes" is:

  1. WILCO
  2. AFFIRMATIVE
  3. ROGER
  4. AFFIRM
Show answer

Answer: D. AFFIRM

AFFIRM = Yes; NEGATIVE = No / permission not granted / that is not correct.

Q8An ELT transmits on:

  1. 121.5 MHz, 243 MHz and 406 MHz
  2. 1 090 MHz
  3. 118 MHz
  4. 125.5 MHz only
Show answer

Answer: A. 121.5 MHz, 243 MHz and 406 MHz

Modern ELTs transmit on 406 MHz (digitally, with a 121.5 homing signal).

Q9The SSR interrogation frequency is:

  1. 1 575 MHz
  2. 1 090 MHz
  3. 1 030 MHz
  4. 121.5 MHz
Show answer

Answer: C. 1 030 MHz

Replies are on 1 090 MHz.

Q10A direct entry into a holding pattern is made when the aircraft arrives at the fix with a track within:

  1. the 180° sector that covers tracks from 70° left to 110° right of the inbound track (right-hand pattern)
  2. the 70° sector on the holding side
  3. within 20° of the inbound track
  4. the 110° sector on the holding side
Show answer

Answer: A. the 180° sector that covers tracks from 70° left to 110° right of the inbound track (right-hand pattern)

Direct sector 180°, parallel sector 110°, teardrop sector 70° (the 70° line is drawn through the holding fix).

Q11A STAR is:

  1. a radar service
  2. a stop alert
  3. a standard instrument arrival route
  4. a position report
Show answer

Answer: C. a standard instrument arrival route

SID is a standard instrument departure; STAR is a standard arrival.

Q12A VFR flight in Class D airspace must:

  1. receive IFR clearance
  2. no radio
  3. establish two-way radio communication and obtain ATC clearance
  4. be separated from all flights
Show answer

Answer: C. establish two-way radio communication and obtain ATC clearance

Class D requires continuous two-way radio communication and a clearance.

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More DGCA Air Regulations topics

ICAO, Annexes & Conventions133 QAircraft Act, Rules & DGCA75 QRegistration & Airworthiness39 QLicensing & Medical45 QRules of the Air176 QAerodromes, Lighting & Marking173 QDistress, Emergency & Communications61 QAccidents, Incidents & Security35 QOperations, Crew & Public Health93 QHuman Performance & Limitations184 QCharges, Documents & Other142 Q
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