ENR 1.6 ATC SURVEILLANCE SERVICES AND PROCEDURES
1 Primary radar
1.1 Doha primary radar equipment is located at:
- RADAR 1 (ASR/PSR): DOHA APP - 251419.90N 0513552.20E
2 Secondary surveillance radar (SSR)
2.1 Doha secondary surveillance radar equipment is located at:
- RADAR 1 (ASR/SSR) : DOHA APP - 251419.90N 0513552.20E
- RADAR 2 (SSR) : DOHA APP - 251541.70N 0513428.60E
2.2 Radar Coverage - Range: 200 NM centered on position 251611.00N 0513401.00E.
3 Automatic dependent surveillance - Broadcast (ADS-B)
3.1 ADS-B Coverage - Range: 250 NM centered on position 251611.00N 0513401.00E.
4 SUPPLEMENTARY SERVICES
4.1 General
4.1.1 Doha Radar operates as the primary air traffic control service within Doha FIR; it provides radar control service to the maximum extent practicable to meet the operational requirement. Many factors, such as radar coverage, controller workload and equipment capabilities may affect the service. Radar controller will determine whether it shall be provided, or continued to provide radar service in any specific way.
4.1.2 The pilot will know when and which radar service is provided, the radar controller uses one of the following ATS call signs "DOHA RADAR", "DOHA APPROACH", "DOHA DIRECTOR" or “DOHA CONTROL”.
4.2 The application of radar control service
4.2.1 Radar identification is achieved according to the provisions specified by ICAO.
4.2.2 Radar control service is provided in controlled airspaces to aircraft operating within Doha TMA and on airways within Doha Radar coverage (delegated by adjacent Area Control Centers as agreed in the Letter of Agreement). These services may include:
- Radar separation of arriving, departing and en-route traffic;
- Radar monitoring of arriving, departing and en-route traffic to provide information on any significant deviation from normal flight path;
- Radar vectoring when required;
- Assistance to aircraft in emergency;
- Assistance to aircraft crossing controlled airspace;
- Warnings and position information on other aircraft considered to constitute a hazard;
- Information to assist in the navigation of aircraft;
- Information on observed weather.
4.2.3 Minimum horizontal radar separation is provided as follows:
- From the centre point of the radar coverage up to 40 NM - 3 NM radar separation.
- Beyond 40 NM - 5 NM radar separation.
4.2.4 The altitude assigned to aircraft by a radar controller provides a minimum terrain clearance during the departure and arrival phase of the flight.
4.2.5 RE-CATEGORISATION WAKE TURBULENCE SEPARATION MINIMA (RECAT)
4.2.5.1 RECAT wake turbulence separation minima is based on aircraft wake turbulence groups according to the maximum certificated take-off mass, wing span and speed, which govern the wake generation and resistance characteristics of the aircraft.
4.2.5.2 The wake turbulence groups are:
- GROUP A - aircraft types of 136 000 kg or more, and a wing span less than or equal to 80 m but greater than 74.68 m;
- GROUP B - aircraft types of 136 000 kg or more, and a wing span less than or equal to 74.68 m but greater than 53.34 m;
- GROUP C - aircraft types of 136 000 kg or more, and a wing span less than or equal to 53.34 m but greater than 38.1 m;
- GROUP D - aircraft types less than 136 000 kg but more than 18 600 kg, and a wing span greater than 32 m;
- GROUP E - aircraft types less than 136 000 kg but more than 18 600 kg, and a wing span less than or equal to 32 m but greater than 27.43 m;
- GROUP F - aircraft types less than 136 000 kg and a wing span less than 27.43 m;
4.2.5.3 The following RECAT wake turbulence separation minima shall be applied to arrival aircraft being provided with an ATS surveillance service on approach to Hamad and Doha International Airports.
4.2.5.4 Arriving Aircraft
Distance based minimum RECAT Separation shall be used
| Leader | Follower | |||||
|---|---|---|---|---|---|---|
| CAT A | CAT B | CAT C | CAT D | CAT E | CAT F | |
| CAT A | 3 NM | 4 NM | 5 NM | 5 NM | 6 NM | 8 NM |
| CAT B | 3 NM | 4 NM | 4 NM | 5 NM | 7 NM | |
| CAT C | 3 NM | 3 NM | 4 NM | 6 NM | ||
| CAT D | 5 NM | |||||
| CAT E | 4 NM | |||||
| CAT F | 3 NM | |||||
4.2.5.5 Departing Aircraft
Time based minimum RECAT Separation shall be used
| Leader | Follower | |||||
|---|---|---|---|---|---|---|
| CAT A | CAT B | CAT C | CAT D | CAT E | CAT F | |
| CAT A | 100s | 120s | 140s | 160s | 180s | |
| CAT B | 100s | 120s | 140s | |||
| CAT C | 80s | 100s | 120s | |||
| CAT D | 120s | |||||
| CAT E | 100s | |||||
| CAT F | 80s | |||||
4.2.5.6 In the event of consecutive missed approaches, RECAT will be applied to aircraft during the initial part of the standard missed approach procedure until another form of separation is established by ATC.
4.2.5.7 Wake Turbulence Separation Minima shall not be infringed. In the event of unexpected speed variations between consecutive arrivals on final approach and ATC considers there may be a catch-up situation in which an erosion of the prescribed separation would result, one of the affected aircraft shall be instructed to break off the approach or initiate a missed approach before the prescribed minima is infringed.
4.2.5.8 Aircrew shall comply with published speed restrictions or specific speed control instructions assigned by ATC at all times. If for any reason a speed instruction cannot be followed, pilots shall notify ATC accordingly.
4.3 Emergency procedures
4.3.1 Except when encountering a state of emergency, pilots shall operate transponders and select modes and codes in accordance with ATC instructions. In particular, when entering Doha FIR, pilots who have already received specific instructions from an Area Control Center concerning the setting of the transponder shall maintain that code setting until otherwise instructed.
4.3.2 All aircraft that are about to enter Doha FIR who have not received specific instructions from Doha Radar concerning the setting of the transponder shall operate the transponder on Mode A / 3 Code A2000 before entry and maintain that setting until otherwise instructed.
4.3.3 If an aircraft encountering a state of emergency which was previously been instructed by ATC to operate the transponder on a specific code, this code setting shall be maintained until otherwise advised.
4.3.4 In all other circumstances, the transponder shall be set to Mode A / 3 Code 7700. Notwithstanding the procedure in ENR 1.6.4.3.1, a pilot may select Mode A / 3 Code 7700 whenever the nature of the emergency is such that this appears to be the most suitable course of action
Note: Continuous monitoring of responses on Mode A / 3 Code 7700 is provided.
4.4 Radar and Radio communication failure procedures
4.4.1 Radar failure
In the event of radar failure or loss of radar identification, instructions will be issued to restore non-radar standard separation and the pilot will be instructed to communicate with the parent ATS unit.
4.4.2 Air-ground communication failure
4.4.2.1 The radar controller will establish whether the aircraft radio receiver is working by instructing the pilot to carry out a turn or turns. If the turns are observed, the radar controller will continue to provide radar service to the aircraft.
4.4.2.2 If the aircraft's is completely unserviceable, the pilot should carry out the procedures for radio communication failures in accordance with ENR 1.6.4.4.3. If radar identification has already been established, the radar controller will vector other identified aircraft clear of its track until such time as the aircraft leaves Doha Radar area of responsibility or has landed.
4.4.3 Radio communication failure procedure
4.4.3.1 General
In the event of an apparent radio communication failure, the pilot of an aircraft should:
- Maintain Terrain Clearance at all times;
- Squawk 7600;
- Contact appropriate alternate and secondary published ATS frequencies;
- Check aircraft communications equipment;
- Listen to ATIS;
- Broadcast intentions (assuming aircraft transmitter is functioning) and prefix transmission with "TRANSMITTING BLIND"
4.4.3.2 Visual Meteorological Condition (VMC)
If a pilot of an aircraft is flying in VMC and is certain that VMC can be maintained, the pilot should:
- Continue to fly in VMC;
- Land at the nearest suitable aerodrome;
- Report arrival by the most expeditious means to the appropriate ATC unit.
4.4.3.3 Instrument Meteorological Condition (IMC)
If the pilot of an aircraft is flying in IMC or is uncertain that a VMC can be maintained, the pilot should:
- Maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of three (3) minutes following:
- the last assigned level or minimum flight altitude is reached; or
- the last time the transponder is set to Code 7600;
whichever is later, and thereafter adjust level and speed in accordance with the filed flight plan; or
- If being vectored, proceed in the most direct manner possible to rejoin the current flight plan route no later than the next significant point, taking into consideration the applicable minimum flight altitude;
- When on arrival, follow (1) and (2) as applicable, then:
- proceed according to the current flight planned route to appropriate designated navigation aid or fix, if necessary, to ensure compliance with (b) below;
- if cleared on a STAR, commence descent from the holding fix associated with the STAR as close as possible to the Expected Approach Time (EAT) last received and acknowledged. If no EAT has been received, commence descent from the holding fix associated with the STAR as close as possible to the Expected Time of Arrival (ETA) resulting from the flight plan. Follow the Radio Communication Procedure shown on the relevant STAR chart;
- in the event a STAR clearance has not been issued, select code 7600 and follow the STAR most appropriate to the inbound route and last known landing runway.
4.5 Unlawful interference procedures
Pilots of the aircraft in flight subjected to unlawful interference shall endeavour to set the transponder to Mode A Code 7500 to give indication of the situation, unless circumstances warrant the use of A / 3 Code 7700.
Note: Continuous monitoring of responses on Mode A / 3 Code 7500 is provided.
4.6 Graphic portrayal of coverage areas
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