Reference: Annex 11 · Doc 4444 · AIP India · CAR Section 9 – Air Space & Air Navigation Services Standards
Series 'E', Part I Issue II · Revision dated 9th November 2018
Capt. Pankaj Pahil
1. Objectives of Air Traffic Services
Core Definition
The primary purpose of ATS is to maintain safe, orderly, and efficient air traffic operations across all phases of flight. Five objectives are prescribed under ICAO Annex 11.
Prevent collisions between aircraft.
Prevent collisions between aircraft on the manoeuvring area and obstructions on that area.
Expedite and maintain an orderly flow of air traffic.
Provide advice and information useful for the safe and efficient conduct of flights.
Notify appropriate organisations regarding aircraft in need of search and rescue aid, and assist such organisations as required.
Memory Aid
"2 Prevent + 1 Expedite + 1 Advise + 1 Notify" — objectives a, b, c are served by ATC; d by Flight Information Service; e by Alerting Service.
2. Divisions of Air Traffic Services
ATS comprises three services:
Fig 1 – The three divisions of Air Traffic Services and their objectives
2.1 Air Traffic Control Service (ATC)
ATC accomplishes objectives a, b, and c. It is divided into three parts:
a) Area Control Service
Provision of ATC service for controlled flights, except for those parts described in approach and aerodrome control service. Accomplishes objectives a and c. Provided by: Area Control Centre (ACC), or by the Approach Control unit where no ACC is established.
b) Approach Control Service
Provision of ATC service for controlled flights associated with arrival or departure. Accomplishes objectives a and c. Provided by: Aerodrome Control Tower / ACC (combined), or by a separate Approach Control Unit.
c) Aerodrome Control Service
Provision of ATC service for aerodrome traffic, except parts covered by Approach Control. Accomplishes objectives a, b, and c. Provided by: Aerodrome Control Tower (ACT).
2.2 Flight Information Service (FIS)
Provided to accomplish objective d — advice and information for safe and efficient flight conduct.
2.3 Alerting Service
Provided to accomplish objective e — notifying SAR organisations and assisting them.
3. Provisions of Control Service – AIP India
3.1 Radio Communication Establishment
Procedure
Radio communication shall be established with the appropriate Aerodrome / Approach Control Unit:
Prior to taxiing for departure; or
When intending to operate in a Class C and D airspace.
Critical Rule – Communication
While operating in Class C and D airspace, only direct controller-pilot communication is permitted. RTF communication through an interpreter shall NOT be permitted.
3.2 Equipment Requirements – Class C & D
Equipment Required
For IFR or VFR operation in Class C and D airspace, aircraft shall be equipped with:
Appropriate two-way VHF radio apparatus
A radio compass
3.3 Entering a CTR or ATZ
Procedure
A pilot-in-command under IFR or VFR intending to enter, cross, or operate within a CTR or ATZ shall request a Clearance from the Aerodrome/Approach Control on the appropriate radio frequency.
The pilot shall:
Pass the aircraft's position, level, track and estimated time of crossing the airspace.
Maintain a continuous listening watch on that frequency while the aircraft is within the airspace.
Carry out any instructions received from Aerodrome/Approach Control.
4. Classification & Designation of ATS Airspace in India
4.1 Designation of Airspace Portions
Flight Information Regions (FIR)
Portions where Flight Information Service and Alerting Service will be provided are designated as Flight Information Regions.
Control Areas & Control Zones
Portions where ATC service will be provided to IFR flights are designated as Control Areas or Control Zones. Where ATC is also provided to VFR flights, these are designated as Class B, C, or D airspace.
Controlled Aerodromes
Aerodromes where ATC service will be provided to aerodrome traffic are designated as Controlled Aerodromes.
4.2 Airspace Classes in India
Implementation Status
Class A* and Class B* — Implementation under consideration. Not yet fully implemented in India.
Class A*
Applicable to designated airspaces in TCA, CTA, and CTZ. IFR flights only are permitted. All flights provided with ATC service and separated from each other.
Class B*
Applicable to designated airspaces in TCA, CTA, and CTZ. IFR and VFR flights permitted. All flights provided with ATC service and separated from each other.
Class C
IFR and VFR flights permitted. All flights provided with ATC service. IFR separated from IFR and from VFR. VFR separated from IFR; VFR receives traffic information in respect of other VFR flights.
Class D
IFR and VFR flights permitted. All flights provided with ATC service. IFR separated from IFR only; IFR receives traffic info about VFR. VFR receives traffic information on all other flights (no separation from VFR).
Class E
Airspace within ATS Route segment outside controlled airspace. IFR and VFR flights permitted. IFR separated from IFR. All flights receive traffic info as far as practical. Class E shall NOT be used for Control Zones.
Class F
Airspace within ATS Route segment outside controlled airspace. IFR and VFR flights permitted. Participating IFR flights receive Air Traffic Advisory Service. All flights receive Flight Information Service if requested.
Class G
Airspace outside ATS route segment and outside controlled airspace. IFR and VFR flights permitted. Flights receive Flight Information Service if requested. No separation provided.
Boundary Note – Vertical Adjacency
Where ATS airspaces adjoin vertically (one above the other), flights at a common level comply with requirements of the less restrictive class of airspace. Order: A (most restrictive) → B → C → D → E → F → G (least restrictive).
1. ATC for separation from IFR; 2. VFR/VFR traffic info (avoidance advice on request)
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
Yes
D
IFR
IFR from IFR
ATC incl. traffic info about VFR (avoidance advice on request)
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
Yes
VFR
Nil
IFR/VFR & VFR/VFR traffic info (avoidance advice on request)
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
Yes
E
IFR
IFR from IFR
ATC and, as far as practical, traffic info about VFR flights
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
Yes
VFR
Nil
Traffic information as far as practical
250 kt IAS below 3050m (10,000 ft) AMSL
No
No
F
IFR
IFR from IFR (as far as practicable)
Air Traffic Advisory Service; Flight Information Service
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
Yes
VFR
Nil
Flight Information Service
250 kt IAS below 3050m (10,000 ft) AMSL
No
No
G
IFR
Nil
Flight Information Service
250 kt IAS below 3050m (10,000 ft) AMSL
Continuous two-way
No
VFR
Nil
Flight Information Service
250 kt IAS below 3050m (10,000 ft) AMSL
No
No
** When transition altitude is lower than 3600m (10,000 ft) AMSL, FL 100 should be used in lieu of 10,000 ft. * Implementation of Class A & Class B under consideration.
5. Procedures in Class C Airspace (India-Specific)
Designation Criteria
Airports with runway handling capacity of >20 aircraft/hour AND equipped with primary and secondary radars are designated Class C. Class C extends from 4000 ft to FL 285. Airspace up to 30 NM around these airports = Class D. Airspace above FL 285 = proposed Class A.
VFR flights must ensure they can meet Class C requirements (MET/COM/SPEED).
Pre-departure clearance from appropriate ATC shall be obtained by all VFR flights intending to enter Class C.
Aircraft on SID/STAR shall follow published speed restrictions.
All aircraft shall follow any additional speed restrictions when instructed by ATC.
Responsibility of terrain clearance remains with the flight crew of VFR flights at all times.
VFR flights unable to adhere to ATC clearance shall obtain alternate clearance.
6. FIRs and Location Indicators
6.1 Flight Information Regions (FIRs)
Flight Information Centres are established to provide FIS and Alerting Service outside controlled airspaces. FIRs are delineated to cover the whole air route structure to be served.
Key Rule
A FIR includes all airspace within its lateral limits, except as limited by an Upper FIR (UIR).
6.2 ICAO Location Indicators – Structure
4-Letter Location Indicator
ICAO has divided the world into 22 non-overlapping AFSRAs. Each AFSRA has a unique identifying letter.
Structure of a 4-letter indicator: 1st letter → Identifies the AFSRA 2nd letter → Identifies the State/Country 3rd & 4th letters → Identify the Place/Station
India's AFSRA letter = V. The 2nd alphabets assigned to India are: I, E, A, O.
Examples: A791, B209. Domestic India routes start with W (e.g. W49). Route designators A,B,G,R,W = Amber, Blue, Green, Red, White.
SIDs & STARs
NDB/VOR/Significant Point + number [+ alphabet suffix]
Examples: LETPU 1D = Departure, SSB 1A = Arrival
7.1 ATS Route Designator Letters – Selection
Letter Group
Route Type
A, B, G, R
Routes forming part of regional networks of ATS routes — NOT area navigation routes
L, M, N, P
Area navigation routes forming part of regional networks
H, J, V, W
Routes NOT forming part of regional networks — NOT area navigation routes
Q, T, Y, Z
Area navigation routes NOT forming part of regional networks
7.2 Supplementary Prefix Letters
Prefix Rules
K — Low-level route established primarily for helicopters
U — Route established in the upper airspace
S — Route established exclusively for supersonic aircraft during acceleration, deceleration, and supersonic flight
Total characters in designator: SHALL NOT exceed 6; should be kept to maximum 5 where possible.
7.3 Supplementary Suffix Letters
Suffix Rules
F — Advisory service only provided on that route/portion
G — Flight information service only provided on that route/portion
8. Special Airspace Areas – P, R, D, TSA, TRA
8.1 Identification System for P, R, D Areas
Identification = Nationality letters + P/R/D + Unduplicated number
Type
Letter
Definition
Example
Prohibited Area
P
Airspace above land/territorial waters of India within which flights are NOT permitted at any time under any circumstances
VA(P)-2 = Prohibited Area No. 2 in Mumbai FIR
Restricted Area
R
Airspace above land/territorial waters of India within which flight of aircraft is restricted
VO(R)-81 = Restricted Area No. 81 in Chennai FIR
Danger Area
D
Airspace within which activities dangerous to flight exist at specified times (notified by NOTAMs)
VE(D)-72 = Danger Area No. 72 in Calcutta FIR
8.2 Military Exercise and Training Areas
TSA – Temporary Segregated Area
Airspace temporarily segregated and allocated for the exclusive use of a particular user during a determined period. Other traffic will NOT be allowed to transit.
Identifier:TSA + number (501–999) + space + [place name in square brackets].
For multiple sub-areas: number followed by capital letter in round brackets. Example:TSA801(A) [Thanjavur]
TRA – Temporary Reserved Area
Airspace temporarily reserved for specific use, but through which other traffic may be allowed to transit under ATC clearance.
Identifier:TRA + number (501–999) + space + [place name in square brackets]. Example:TRA601(A) [Panagarh]
Number Allocation – TSA/TRA
A single series (501–999) is used for both TSA and TRA regardless of type. A number is NOT duplicated in any type.
Mumbai FIR
501 – 600
Kolkata FIR
601 – 700
Delhi FIR
701 – 800
Chennai FIR
801 – 900
Reserved for Future Use
901 – 999
9. Control Areas and Control Zones
9.1 Control Areas (CTA)
Control areas (including airways and terminal control areas) shall be delineated to encompass sufficient airspace to contain flight paths of IFR flights.
Lower Limit of Control Area
A lower limit of a Control Area shall be established at a height above the ground or water of not less than 200 m (700 ft).
9.2 Control Zones (CTR)
Control zone lateral limits encompass portions of airspace not within control areas, containing paths of IFR flights arriving at and departing from aerodromes under IMC.
Lateral Limit of CTR
Shall extend to at least 9.3 km (5 NM) from the centre of the aerodrome(s) in the directions from which approaches may be made.
Notes
Aircraft holding in the vicinity of aerodromes are considered as arriving aircraft.
A control zone may include two or more aerodromes situated close together.
9.3 Local / Training Flights
Procedure
For local training/test flights by scheduled/non-scheduled operators: flight plan submitted as for non-scheduled flights.
For training flights by flying clubs within ATZ: flight plan may be submitted by Fax or telephone.
If no ATZ established and no reserved airspace: an area of 5 NM radius from ARP, up to 3000 ft AGL = vicinity of aerodrome for VFR.
For cross-country flights from airfields with no ATS reporting office: flight plan submitted to FIC by Fax. Must include accumulated elapsed times to FIR boundary points and contact tel/mobile of PIC in Field 18.
9.4 Identification of ATS Units and Airspaces
An Area Control Centre or FIC → identified by name of a nearby town/city or geographic feature.
An Aerodrome Control Tower or Approach Control Unit → identified by name of the aerodrome.
A Control Zone, CTA, or FIR → identified by name of the unit having jurisdiction over that airspace.
9.5 Upper Airspace FIRs / Control Areas
To limit the number of FIRs or CTAs through which high-flying aircraft operate, a FIR or CTA may be delineated to include upper airspace within the lateral limits of a number of lower FIRs or CTAs.
10. Air Traffic Control Service
10.1 Application – Where ATC is Provided
To all IFR flights in airspace Classes A, B, C, D and E.
To all VFR flights in airspace Classes B, C and D.
To all special VFR flights.
To all aerodrome traffic at controlled aerodromes.
10.2 Separation Provided by ATC Clearances
Clearances shall provide separation:
Between all flights in airspace Classes A and B.
Between IFR flights in airspace Classes C, D and E.
Between IFR and VFR flights in airspace Class C.
Between IFR and Special VFR flights.
Between Special VFR flights when so prescribed by the appropriate ATS authority.
Separation Minima
Selection of separation minima within a given airspace shall be as per provisions of PANS-ATM and Regional Supplementary Procedures.
10.3 Read-back of Clearances and Safety-Related Information
Mandatory Read-back Items
The flight crew shall read back safety-related parts of ATC clearances/instructions. The following shall ALWAYS be read back:
ATC route clearances
Clearances and instructions to enter, land on, take off from, hold short of, cross and backtrack on any runway
Runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions, and whether issued by the controller or contained in ATIS broadcasts, transition levels
Controller Obligation
The controller shall listen to the read-back to ascertain that the clearance has been correctly acknowledged and shall take immediate action to correct any discrepancies. Voice read-back of CPDLC messages shall NOT be required.
10.4 Service to Aircraft in Emergency
Emergency Priority
An aircraft known or believed to be in a state of emergency, including being subjected to unlawful interference, shall be given maximum consideration, assistance and priority over other aircraft.
Transponder Code
Meaning
Mode A, 7700
General Emergency
Mode A, 7500
Unlawful Interference (Hijack)
Also: activate ADS emergency/urgency capability OR transmit emergency message via CPDLC
10.5 Air Traffic Flow Management (ATFM)
ATFM is primarily meant to balance demand against capacity to achieve optimum utilisation of major resources — Airport, Airspace, and Aircraft — at every Indian airport where there is a capacity constraint.
India's C-ATFM System
AAI has established a Central Air Traffic Flow Management (C-ATFM) system consisting of:
Central Command Center (CCC) at Delhi
Flow Management Positions (FMPs) at major ACCs and ATC towers
Phase I: FMPs at Delhi, Mumbai, Bengaluru, Chennai, Kolkata, Hyderabad (handle 60% of Indian air traffic)
Phase II: FMPs at additional 30 airports (phased manner)
11. Flight Information Service (FIS)
11.1 Application
FIS shall be provided to all aircraft which are likely to be affected by the information and which are:
Provided with air traffic control service; or
Otherwise known to the relevant ATS units.
11.2 Scope of FIS – Information Included
FIS Includes
SIGMET and AIRMET information (Note: AIRMET is NOT provided in India).
Information on pre-eruption volcanic activity, eruptions, volcanic ash clouds.
Information on release of radioactive materials or toxic chemicals into atmosphere.
Changes in serviceability of navigation aids.
Changes in condition of aerodromes and associated facilities (including state of movement areas affected by snow, ice, or significant depth of water).
Information on unmanned free balloons and any other information likely to affect safety.
11.3 FIS Provided to Flights
Weather conditions at departure, destination and alternate aerodromes.
Collision hazards for aircraft operating in airspace Classes C, D, E, F and G.
For flights over water: radio call sign, position, track, speed of surface vessels (if requested and practicable).
11.4 FIS to VFR Flights
FIS provided to VFR flights shall include traffic and weather conditions along the route likely to make operation under visual flight rules impracticable.
12. Automatic Terminal Information Service (ATIS)
12.1 Voice-ATIS Broadcasts
Purpose
Provided at aerodromes where there is a requirement to reduce the communication load on the ATS VHF air-ground communication channels.
Critical Rules – Voice-ATIS
A discrete VHF frequency shall, whenever practicable, be used.
If discrete freq unavailable, may use VOR voice channel — but NOT on ILS voice channel.
Broadcast shall be continuous and repetitive.
Message should, whenever practicable, NOT exceed 30 seconds.
12.2 D-ATIS (Data Link ATIS)
Where D-ATIS supplements Voice-ATIS, the information shall be identical in both content and format to the Voice-ATIS broadcast.
12.3 ATIS Operational Rules
When ATIS is Provided:
Information relates to a single aerodrome.
Updated immediately a significant change occurs.
Preparation and dissemination is the responsibility of Air Traffic Services.
Each message identified by a letter of the ICAO spelling alphabet (designators in alphabetical order).
Aircraft shall acknowledge receipt upon establishing communication with the ATS unit.
ATS unit provides aircraft with current altimeter setting upon reply.
Meteorological information extracted from the local met routine or special report.
If rapidly changing conditions, ATIS shall indicate that relevant weather info will be given on initial contact.
Information in a current ATIS (acknowledged by aircraft) need not be re-transmitted, except the altimeter setting.
12.4 ATIS Message Contents (Arriving and Departing)
Item
Content
a
Name of aerodrome
b
Arrival and/or departure indicator
c
Contract type (if D-ATIS)
d
Designator (ICAO alphabet letter)
e
Time of observation (if appropriate)
f
Type of approach(es) to be expected
g
Runway(s) in use; status of arresting system (if any)
Surface wind direction and speed (incl. significant variations)
*m
Visibility and, when applicable, RVR
*n
Present weather
*o
Cloud below 1500m (5000 ft) or below highest MSA (whichever greater); cumulonimbus; vertical visibility if sky obscured
p
Air temperature
q
Dew point temperature
r
Altimeter setting(s)
s
Significant meteorological phenomena in approach/climb-out areas; wind shear; recent weather
t
Trend forecast (when available)
u
Specific ATIS instructions
* Items m, n, o are replaced by "CAVOK" whenever visibility, cloud and present weather are better than prescribed values.
12.5 Runway Surface Condition Reporting Terms
Effective November 2021
Standardised terms for runway surface conditions affecting braking:
COMPACTED SNOW
DRY
DRY SNOW
DRY SNOW ON TOP OF COMPACTED SNOW
DRY SNOW ON TOP OF ICE
FROST
ICE
SLUSH
STANDING WATER
WATER ON TOP OF COMPACTED SNOW
WET
WET ICE
WET SNOW
WET SNOW ON TOP OF COMPACTED SNOW
WET SNOW ON TOP OF ICE
Friction measuring devices shall correlate in a manner acceptable to DGCA.
13. Alerting Service
13.1 Application
Alerting service shall be provided:
For all aircraft provided with ATC service.
As far as practicable, to all aircraft having filed a flight plan or otherwise known to ATS.
To any aircraft known or believed to be subject of unlawful interference.
Central Point for Emergency Info
Flight Information Centres or Area Control Centres serve as the central point for collecting all information relevant to a state of emergency and forwarding to the appropriate Rescue Coordination Centre.
13.2 The Three Emergency Phases
INCERFA
Uncertainty Phase
No communication for 30 minutes after it was due, or from time of unsuccessful attempt
Aircraft fails to arrive within 30 minutes of ETA (last notified/estimated), if no doubt about safety
ALERFA
Alert Phase
Following INCERFA, further attempts to contact aircraft and inquiries have failed
Aircraft cleared to land, fails to land within 5 minutes of ETA, comm not re-established
Operating efficiency impaired but forced landing NOT likely
Aircraft known/believed subject of unlawful interference
DETRESFA
Distress Phase
Following ALERFA, further attempts indicate aircraft probably in distress
Fuel on board considered exhausted or insufficient to reach safety
Operating efficiency impaired to extent that forced landing is likely
Information received that forced landing is about to be or has been made
When ATS believes an aircraft is being subjected to unlawful interference, no reference shall be made in ATS air-ground communications to the nature of the emergency unless it has first been referred to in communications from the aircraft and it is certain such reference will NOT aggravate the situation.
14. ATS Routes in India – Rules and Requirements
ATC Clearance Requirements
Aircraft shall obtain ATC clearance from appropriate ATS unit at least 10 minutes prior to entering controlled airspace.
Aircraft shall NOT join or cross ATS routes without prior approval/ATC clearance:
At least 10 minutes prior if in direct VHF contact.
At least 20 minutes prior if contact is through en-route radio frequency.
All aircraft transiting from one FIR to another shall forward estimates for FIR boundary (including FL) to the ATS unit of the FIR to be entered, at least 10 minutes prior. (Does NOT apply between Indian FIRs — only entering Indian FIR from a foreign FIR.)
Crossing ATS Routes
Aircraft will join or cross ATS routes at or close to a designated reporting point.
Crossing shall be done at 90° to the direction of the route and at a level appropriate to the magnetic track.
VFR flights to cross ATS routes outside controlled airspace shall only cross at an appropriate VFR level at right angle to the direction of the ATS route.
Position Reporting
On routes defined by significant points: report as soon as possible after passing each designated reporting point.
On routes NOT defined by significant points: report after the first half hour of flight and at hourly intervals thereafter. Additional reports at shorter intervals may be requested by ATC.
International Border Rule
All aircraft are forbidden to operate within 15 NM of the international border of India unless specifically permitted, following an ATS route, or operating to/from an aerodrome situated within 15 NM of the border.
MFA Obstacle Clearance
Minimum flight altitude on ATS routes is determined to ensure at least 1000 ft (300 m) vertical clearance above the highest obstacle within 10 KM on each side of the centre line of the route.
Flying Outside ATS Routes
Flying outside of ATS routes is prohibited within Indian FIRs, unless otherwise authorised by ATC. Scheduled international flights are permitted to flight plan using domestic ATS route segments to/from destination, departure and approved alternate airports not connected by international ATS Routes.
14.1 ATS Route Description in AIP (With effect 4/11/2021)
AIP Section
Old Description
New Description
ENR 3.1
Lower ATS Routes
Conventional Navigation Routes
ENR 3.2
Upper ATS Routes
Air Navigation Routes
14.2 Types of Services (at Civil Aerodromes)
Services Provided (except at Military Bases)
Air Traffic Control Service
Air Traffic Advisory Services
Flight Information Service and Alerting Service
Surveillance Services
Note: There is no distinction between upper and lower controlled airspace in India.
14.3 Strayed Aircraft
Definition
An aircraft that has deviated significantly from its intended track or reports that it is lost. An aircraft may be considered "strayed" by one unit and "unidentified" by another. ATS takes all necessary steps to assist and safeguard its flight.
14.4 Air Traffic Advisory Service
Provided to aircraft operating outside controlled airspace on ATS routes classified "F".
Advisory Service vs ATC
IFR flights using advisory service in Class F comply with same procedures as controlled flights except that the flight plan and changes are NOT subject to clearance. The unit only provides advice on essential traffic and suggests possible courses of action.
15. Practice Questions with Answers
All 78 questions from the textbook with correct answers highlighted in green. Use for self-assessment.
1A lower limit of a Control Area shall be established at a height above the ground level or water of not less than:
A) 150 metres
B) 200 metres
C) 300 metres
2The Approach Control Service is an air traffic control service:
A) provided for the arriving and departing controlled flights
B) for IFR flights arriving and departing
C) provided for IFR traffic within a Control Zone
3The units providing Air Traffic Services are:
A) Area Control Center – Advisory Center – FIC – Approach Control Office and Tower
B) Area Control Center – FIC – Approach Control Office – Aerodrome Control Tower and ATS reporting office
C) Area Control Center – Approach Control Office and Aerodrome Control Tower only
4Air traffic control service is provided for the purpose of:
A) Avoiding collisions between all aircraft and maintaining an orderly flow of air traffic
B) Preventing collisions between aircraft, between aircraft and obstacles on the manoeuvring area and expediting and maintaining an orderly flow of air traffic
C) Preventing collisions between controlled air traffic and expediting and maintaining an orderly flow of air traffic
5To perform a VFR flight in airspace classification E:
A) a clearance and/or two-way radio communication is required
B) a clearance is required
C) two-way radio communication is not required
6Which statement is correct?
A) The lower limit of a UIR may coincide with an IFR cruising level
B) The lower limit of a TMA shall be established at a height of at least 700ft AGL
C) The upper limit of a CTR shall be established at a height of at least 3000ft AMSL
7What is the speed limit (IAS) in an airspace class E?
A) 250kt VFR and IFR, all levels
B) 250kt for IFR and VFR up to FL 100
C) 250 kt only for IFR up to FL 100
8The speed limitation for IFR flights inside ATS airspace classified as C, when flying below 3050m (1000ft) AMSL, is:
A) 250kt IAS
B) Not applicable
C) 250kt TAS
9RCP 10 means:
A) 10 is the number of seconds it takes for an instruction to travel from the ground to aircraft and acknowledgment back to the ground
B) 10 is the maximum number of minutes it takes for an instruction to be executed by an aircraft
C) Aircraft must communicate with ATC every 10 minutes
10An ATS airspace where IFR and VFR flights are permitted, all flights are subject to air traffic control service and are separated from each other is classified as:
A) Airspace C
B) Airspace B
C) Airspace D
11The speed limitation for both IFR flights and VFR flights inside ATS airspace classified as B, when flying below 3050m (10000ft) AMLS, is:
A) 260kt IAS
B) Not applicable
C) 250kt IAS
12Air traffic services unit clocks and other time recording devices shall be checked as necessary to ensure correct time within plus or minus:
A) 1 minute of UTC at all times
B) 15 seconds of UTC at all times
C) 30 seconds of UTC at all times
13The following airspace falls under Kolkata FIR?
A) VED
B) VEB
C) VOR
14The VMC minima for a VFR flight inside an ATS airspace classified as B, is:
A) 8km visibility when at or above 3050m (10000ft) AMSL and clear of clouds
B) 8km visibility when at or above 3050m (10000ft) AMSL, and 1500m horizontal and 300m vertical from clouds
C) 5NM visibility when below 3050m (10000ft) AMSL, 1500m horizontal and 300m vertical from cloud
15A VFR flight when flying inside an ATS airspace classified as B has to maintain the following minima of flight visibility and distance from clouds:
A) 5km visibility, 1500m horizontal and 300m vertical from clouds
B) 8km below 3050m (10000ft) AMSL, 1500m horizontal and 300m vertical from clouds
C) 5km below 3050m (10000ft) AMSL and clear of clouds
16An ATS airspace where IFR and VFR flights are permitted, all flights are subject to ATC service and IFR flights are separated from other IFR flights and from VFR flights; VFR flights are separated from IFR flights and receive traffic information in respect of other VFR flights, is classified as:
A) Airspace B
B) Airspace E
C) Airspace C
17Which condition is requested so that an aerodrome may be considered controlled?
A) The aerodrome shall be provided with a Control Tower
B) The aerodrome shall be located within a CTR and provided with a Control Tower
C) The aerodrome shall be located within a Control Zone
18An ATS airspace where IFR and VFR flights are permitted and all flights are subject to ATC service. IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights. VFR flights receive traffic information in respect of all other flights, is classified as:
A) Airspace B
B) Airspace D
C) Airspace A
19An ATS airspace where IFR and VFR flights are permitted are subject to ATC Service and are separated from other IFR flights. All flights receive traffic information as far as practical, is classified as:
A) Airspace D
B) Airspace A
C) Airspace E
20An ATS airspace where IFR and VFR flights are permitted, all participating IFR flights receive an air traffic advisory service and all flights receive flight information service if requested, is classified:
A) Airspace F
B) Airspace E
C) Airspace D
21Which statement regarding approach control service is correct?
A) Approach control have to advise aircraft operators about substantial delays in departure when expected to exceed 45 minutes
B) During a visual approach an aircraft is maintaining its own separation
C) If it is anticipated that an aircraft has to hold for 30 minutes or more, an Expected Approach Time will be transmitted by the most expeditious means to the aircraft
22Which statement regarding aerodrome control service is correct?
A) An aircraft entering the traffic circuit without permission of ATC, will be cleared to land if this is desirable
B) Suspension of VFR operations cannot be initiated by the aerodrome controller
C) ATC permission is required for entering the apron with a vehicle
23In ATS route designator UA1Y what does U mean:
A) Upper
B) Undirectional
C) Uniform
24Special VFR flights may be authorized to operate locally within a control zone when the ground visibility is not less than 1500 metres, even when the aircraft is not equipped with a functioning radio receiver within class:
A) D airspace
B) D and E airspace
C) E airspace
25Flight information service shall be provided to all aircraft which are likely to be affected by the information and which are:
A) Provided with the air traffic control services and otherwise known to the relevant air traffic service units
B) Known to the relevant air traffic services units by a filed flight plan
C) Provided with air traffic control services, only
26Alerting service shall be provided:
A) For all controlled flight, to any aircraft known or believed to be subject of unlawful interference, and in so far as practicable to all aircraft having filed a flight plan or otherwise known to the ATS
B) For all aircraft provided with air traffic control services, only
C) To any aircraft known or believed to be subject of unlawful interference, only
27The speed limitation for IFR flights inside ATS airspace classified as E, when flying below 3050m (10000ft) AMSL, is:
A) 250kt TAS
B) 250kt IAS
C) Not applicable
28Air Traffic Service unit means:
A) Air Traffic Control units and Air Services reporting offices
B) Flight Information Centers and Air Services reporting offices
C) Air Traffic Control units, Flight Information Centers or Air Services reporting offices
29A controlled airspace extending upwards from a specified limit above the earth is:
A) Advisory airspace
B) Control area
C) Flight Information Region
30Tirupati aerodrome designator is?
A) VATP
B) VOTP
C) VITP
31Aerodrome traffic is:
A) All traffic on the manoeuvring area and flying in the vicinity of an aerodrome
B) All traffic in the aerodrome circuit
C) All traffic on the manoeuvring area
32Which of the following Annexes to the Chicago convention contains international standards and recommended practices for air traffic services (ATS)?
A) Annex 6
B) Annex 14
C) Annex 11
33An information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect safety of low-level aircraft operations is:
A) An En-Route Met Report
B) A NOTAM
C) An AIRMET information
34Regarding Aerodrome Flight Information (AFIS):
A) Its purpose is to supply ATC services but it is not a state organisation
B) It can only supply limited services to the users and under no circumstances may it supply ATC services
C) It has the same privileges as an ATC organisation but its activity is neither continuous nor regular
35Air Traffic Control service shall be provided to:
A) All IFR flights in class A, B, C, D, E and F airspaces
B) All VFR flights in class B, C, D and E airspaces
C) To all aerodrome traffic at controlled aerodromes
36Flight Information Region (FIR) is an airspace within which the following services are provided:
A) Flight Information Service and Alerting Service
B) Flight Information Service and Advisory Service
C) Flight Information Service, Alerting Service and Advisory Service
37Control Area (CTA) is defined as follows:
A) A controlled airspace extending upwards from a specified limit above the earth
B) A controlled airspace extending upwards from the surface of the earth to a specified limit
C) A controlled airspace extending upwards from a height of 900ft above the earth
38Aerodrome local flying area is to be considered, if ATZ is not notified:
A) Within 5 NM of ARP up to 3000 feet
B) Within 25 NM of ARP up to 10,000 feet
C) Within 10 NM of ARP up to 5000 feet
39An air traffic control unit:
A) May ask an aircraft to temporarily change its callsign for safety reasons when there is a risk of confusion between two or more similar callsigns
B) May not ask an aircraft to change its callsign after accepting the flight plan
C) Must not ask an aircraft to change its callsign
40Required Navigation Performance (RNP) shall be prescribed:
A) By regional air navigation agreements
B) By states but not on the basis of regional air agreements
C) By states on the basis of regional air navigation agreements
41A Control Zone shall extend laterally to at least:
A) 10 miles from the centre of the aerodrome in the direction from which approaches may be made
B) 5 nautical miles from the centre of the aerodrome in the direction from which approaches may be made
C) 20 miles from the centre of the aerodrome in the direction from which approaches may be made
42G245ZF is a designator for:
A) a SID
B) a STAR
C) an ATS Route
43An ATS airspace where IFR and VFR are permitted and receive flight information service if requested, is classified as:
A) Airspace G
B) Airspace E
C) Airspace C
44Concerning RNP types, the indication RNP 4 represents a navigation accuracy of:
A) Plus or minus 4 NM on a 95% containment basis
B) Plus or minus 4 NM on a 98% containment basis
C) Plus or minus 4 NM on a 90% containment basis
45Area Control Centers issue clearances for the purpose of:
A) Achieving separation between IFR flights
B) Achieving separation between controlled flights
C) Providing flight information Service
46Clearances will be issued by an ATC unit for the purpose of:
A) Achieving separation between controlled flights
B) Providing alerting services
C) Providing advisory services
47You receive an IFR enroute clearance starting: Clearance expires at 0920. What does it mean?
A) If not airborne until 0920, a new clearance has to be issued
B) The take off clearance is expected at 0920
C) After 0920 return to the ramp and file a new flight plan
48ATIS broadcast:
A) Shall only be transmitted on a discrete VHF frequency
B) Shall not be transmitted on the voice channel of an ILS
C) Shall not be transmitted on the voice of VOR
49Whenever ATIS is provided, the preparation and dissemination of the ATIS message shall be the responsibility of:
A) Both air traffic services and the meteorological office
B) The meteorological office serving the aerodromes
C) The air traffic services
50Whenever ATIS is provided, the broadcast information shall be updated:
A) As prescribed by the meteorological office
B) Immediately a significant change occurs
C) As prescribed by the state
51The ATIS broadcast message should, whenever practicable, not exceed:
A) 30 seconds
B) 1 minute
C) 2 minutes
52ATIS broadcast messages containing departure and arrival information should include cloud cover, when the clouds are:
A) Below 900m (3000ft) or below the highest minimum sector altitude, whichever is the greater
B) Below 2000m (600ft) or below the highest minimum sector altitude, whichever is the greater
C) Below 1500m (5000ft) or below the highest minimum sector altitude, whichever is the greater
53When are ATIS broadcasts updated?
A) Upon receipt of any official weather, regardless of content change or reported values
B) Every 30 minutes if weather conditions are below those for VFR; otherwise hourly
C) Only when the ceiling and/or visibility changes by a reportable value
54Flight Information Service shall be provided to aircraft in order to avoid collision hazards when operating in airspace classes:
A) F and G only
B) C, D, E, F and G
C) A, B, C, D, E, F and G
55The lateral limit of CTR shall extend to at least ___ NMs from the center of aerodrome in directions from where approaches may be made:
A) 25
B) 10
C) 5
56At radio communications, "Distress" differs from "Urgency" because in the first case:
A) The aeroplane has suffered damages which impair its fitness to fly
B) There is a serious and imminent danger requiring immediate assistance
C) The aeroplane will not be able to reach a suitable aerodrome
57The Alerting Service is provided by:
A) The Area Control Centers
B) The ATS unit responsible for the aircraft at that moment
C) Only by ATC units
58The phases related to an aircraft in emergency or believed in emergency are:
A) Uncertainty phase, distress phase, urgency phase
B) Uncertainty phase, alert phase, distress phase
C) Uncertainty phase, urgency phase, distress phase
59When an aircraft is experiencing difficulties, triggering of the alert phase is the responsibility of:
A) Search and rescue coordination centers
B) Control centers only
C) Air traffic control and flight information centers
60What type of flight is allowed in class A airspace?
A) IFR only
B) IFR and VFR
C) IFR and special VFR
61Alert phase is defined as follows:
A) A situation where an apprehension exists as to the safety of an aircraft and its occupants
B) An emergency event in which an aircraft and its occupants are considered to be threatened by a danger
C) A situation related to an aircraft and its occupants are considered to be in a state of emergency
62A situation in which apprehension exists as to the safety of an aircraft. To which emergency phase does this situation correspond?
A) ALERFA
B) INCERFA
C) DETRESFA
63Which of the following signals is a distress signal?
A) In radiotelephony the spoken words PAN, PAN
B) A parachute flare showing a red light
C) The repeated switching on and off of the navigation lights
64An aircraft is in emergency when:
A) It is threatened by grave danger
B) It is threatened by grave danger and requires immediate assistance
C) It is forced to land
65The different emergency phases (in correct order) are:
A) INCERFA, ALERTFA and DISTRESFA
B) INCERFA, ALERFA, DETRESFA
C) ALERTFA, DISTRESFA, RESCUEFA
66Which of the following statements describes the Alert Phase (ALERFA)?
A) An aircraft fails to arrive within 30 minutes of the ETA which was last notified to ATC
B) An aircraft declares that the fuel remaining is insufficient to reach safety
C) An aircraft which has been cleared to land fails to land within 5 minutes of the ETA and communication has not been re-established
67DETRESFA is where:
A) An aircraft fails to land within 5 minutes of being cleared to land
B) All answers are correct
C) The fuel on board is considered to be exhausted
68RSP 180 indicates:
A) Time in seconds taken by a pilot to receive surveillance instructions from the controller
B) Time in seconds between flight crew/HMI and controller/HMI
C) Distance in NMs between two way points in defined RSP airspace
69A strayed aircraft is an aircraft:
A) that has deviated significantly from its intended track or reports that it is lost
B) that has been observed or is reported to be operating in a given area but whose identity has not been established
C) only that aircraft which has deviated significantly its intended track
70Having filed a flight plan to a particular destination and having landed at another destination, you should notify ATC:
A) within 60 minutes after landing at the alternate destination
B) within 30 minutes after landing at the alternate destination
C) within 30 minutes of your intended ETA at your original destination
71Designated airspace within controlled airspace in India is classified as Class:
A) C
B) D
C) C and D
72TSA801(A) is an airspace:
A) temporarily segregated and allocated in Delhi FIR
B) temporarily segregated and allocated in Chennai FIR
C) denoting an area navigation route in India
73Temporary Reserved Area (TRA) is an airspace temporarily reserved and allocated:
A) through which other traffic may be allowed to transit in VMC only
B) through which other traffic is not allowed to transit without proper equipment
C) through which other traffic may be allowed to transit under ATC clearance
74MFA published in AIP ensures at least 1000 feet vertical clearance from obstacles within ___ of center line?
A) 10 Kms
B) 10 NMs
C) 20 NMs
75Class C airspaces in India extend from ___ to ___.
A) Ground level, FL 150
B) 4000 feet, FL 285
C) FL 150, FL 290
76After rain Controller reports that runway is WET. That indicates to a pilot that:
A) the surface is soaked but there is no standing water
B) there is no standing water with a depth of more than 3 cms on one third of the runway
C) the runway is closed due water logging and pilot should divert
77In AIP, Enroute 3.1, ATS routes are described as:
A) Lower ATS Routes
B) Conventional Navigation Routes
C) RNP routes
78In AIP, Enroute 3.2, ATS routes are described as:
A) Upper ATS Routes
B) Air Navigation Routes
C) Non RNP routes
16. Quick Reference – Key Numbers & Facts
Parameter
Value / Rule
Source
Lower limit of CTA
≥ 200 m (700 ft) AGL
ICAO Annex 11
Lateral limit of CTR
≥ 9.3 km (5 NM) from aerodrome centre in approach directions
ICAO Annex 11
Class C airspace extent in India
4000 ft to FL 285
AIP India
Class D airspace extent (India)
Up to 30 NM around major airports (below Class C)
AIP India
Speed limit (all classes with limit)
250 kt IAS below 3050m (10,000 ft) AMSL
ICAO Annex 11
Aerodrome vicinity (no ATZ)
5 NM radius, up to 3000 ft AGL
AIP India
INCERFA trigger time (no comms)
30 minutes
ICAO Annex 11
INCERFA trigger (late arrival)
30 minutes after last notified ETA
ICAO Annex 11
ALERFA trigger (cleared, no land)
5 minutes after ETA + no comms
ICAO Annex 11
ATIS max duration
30 seconds (whenever practicable)
ICAO Annex 11
ATC clearance before controlled airspace
At least 10 minutes prior (direct VHF)
AIP India
ATC clearance before ATS route entry (en-route radio)
At least 20 minutes prior
AIP India
FIR boundary estimate
At least 10 minutes prior to entry
AIP India
MFA obstacle clearance
1000 ft (300 m) above highest obstacle within 10 km each side of route centre line
AIP India
International border buffer
15 NM — no operations unless specifically permitted
AIP India
ATC clearance crossing ATS route angle
90° to direction of route
AIP India
Transponder – General Emergency
Mode A, 7700
ICAO Annex 10
Transponder – Unlawful Interference
Mode A, 7500
ICAO Annex 10
TSA/TRA number series
501–999 (single series)
AIP India
Delhi FIR TSA/TRA numbers
701–800
AIP India
Mumbai FIR TSA/TRA numbers
501–600
AIP India
Kolkata FIR TSA/TRA numbers
601–700
AIP India
Chennai FIR TSA/TRA numbers
801–900
AIP India
ATIS update trigger
Immediately a significant change occurs
ICAO Annex 11
ATIS acknowledgement — exception
Altimeter setting must always be re-transmitted
ICAO Annex 11
Annex for ATS standards
Annex 11 to Chicago Convention
ICAO
Number of world AFSRAs
22 non-overlapping
ICAO Doc 7910
ATC clocks accuracy
± 30 seconds UTC
ICAO Annex 11
Chapter 5 – Air Traffic Services | DGCA CPL/ATPL Study Notes |
Prepared by Capt. Pankaj Pahil |
Reference: Annex 11 · Doc 4444 · AIP India · CAR Section 9 Series E Part I Issue II (Rev. 9 Nov 2018) |
For examination preparation purposes only — always refer to the latest regulatory publications.