1. General Procedures

1.1 Enroute Airspace Structure

Airspace	Classification	Vertical Limits	Transition Altitude	Transition Level
Doha FIR	Class A above FL150 on Airways	FL150 - UNL	13,000FT	FL 150
Doha FIR	Class C below FL150 on Airways	4500FT - FL150	13,000FT	FL 150
Doha FIR	Class G (except within control areas, control zones, and airways)	SFC - 4500FT	13,000FT	FL 150

1.1.2 Air Traffic Units

Radio Callsign	Logon Callsign	Abbreviation	Frequency
Doha Director (16L/34R)	DOH_F1_APP	FIN E	119.400
Doha Director (16R/34L)	DOH_F2_APP	FIN W	124.050
Doha Final Monitoring Control	DOH_F3_APP	FMC	123.875
Doha Approach (East)	DOH_A1_APP	APP E	124.775
Doha Approach (West)	DOH_A2_APP	APP W	119.725
Doha Radar (North)	DOH_R1_APP	RDR N	121.100
Doha Radar (South)	DOH_R2_APP	RDR S	120.675
Doha Control (North)	OTDF_1_CTR	ACC N	135.725
Doha Control (South)	OTDF_2_CTR	ACC S	132.975

1.1.3 Radar & Surveillance Systems

The Doha Flight Information Region (FIR) is equipped with a total of four MSSR (Monopulse Secondary Surveillance Radar) stations and three PSR (Primary Surveillance Radar) stations. The three primary PSR stations are strategically positioned to provide a detection range of up to 200 nautical miles (NM). Meanwhile, the four MSSR stations provide enhanced surveillance capabilities with a range extending up to 200 NM, allowing radar coverage within the entire FIR.

1.1.4 CPDLC/ADS-C

The Doha Flight Information Region (FIR) does not have operational CPDLC services in place. However, due to the increasing number of aircraft equipped with Hoppie ACARS, our sector files are configured to support CPDLC services enroute above FL295. This proactive configuration aims to accommodate the growing trend of aircraft utilizing CPDLC for communication, ensuring compatibility and readiness for future implementation.

Currently, the Doha FIR does not have ADS-C services implemented. Consequently, aircraft are required to comply with traditional voice reporting procedures for position reporting and coordination. There are no automatic position reporting systems in place within the FIR at this time.

In summary, while CPDLC and ADS-C services are not yet operational in the Doha FIR, the sector files are configured to support CPDLC services to align with the increasing number of equipped aircraft. However, ADS-C services are not currently available, and traditional voice communication remains the primary means for position reporting and coordination.

1.1.5 Flight Data Processing Systems

The Doha FIR utilizes the TopSky Air Traffic Management (ATM) system to support controllers in efficiently managing and tracking flights. TopSky consolidates flight plan information, continuously updates aircraft position data, and provides advanced conflict detection and resolution tools. Controllers rely on this system to maintain situational awareness, coordinate sector handoffs, and optimize traffic flow.

It is critical that aircraft tags within TopSky are kept current at all times. This includes accurate updates of cleared flight levels (CFL), direct routing to waypoints (COPX), headings, vertical speed rates, and speed or Mach number assignments. Maintaining these updates enables TopSky to perform reliable conflict prediction and issue timely alerts, thereby ensuring safe and efficient air traffic management throughout the FIR.

1.1.6 Controller Responsibilities

Controllers operating within the Doha FIR are responsible for ensuring the safe, orderly, and expeditious flow of air traffic within their designated sectors. This includes:

Maintaining continuous surveillance and communication with all assigned aircraft.
Issuing clearances, instructions, and traffic information in accordance with standard operating procedures.
Monitoring compliance with level restrictions, route clearances, and separation minima.
Coordinating timely handoffs with adjacent sectors to maintain seamless traffic flow.
Managing traffic sequencing during peak periods and sector splits.
Reporting any operational irregularities or emergencies promptly.
Ensuring the effective use of available surveillance and communication technologies, including FDPS and CPDLC-enabled services where applicable.

1.2 Separation Minima

1.2.1 Radar Separation

Radar separation is the primary method used within the Doha FIR to ensure safe distances between aircraft under surveillance. Controllers use radar to maintain the following types of separation:

1.2.2 Lateral Separation

Unless otherwise specified, all aircraft operating within the Doha FIR under radar control shall maintain a minimum horizontal radar separation of 5 nautical miles (NM) between each other.

1.2.3 Vertical Separation

If horizontal separation is not feasible, vertical separation shall be used. Vertical separation of 1,000FT shall apply up to and including FL410 within RVSM airspace. Above FL410, a vertical separation of 2,000FT is required unless both aircraft are RVSM-approved.

1.2.4 Longitudinal Separation (time/distance-based)

Aircraft operating enroute on the same airway and at the same flight level shall be separated by a minimum longitudinal distance of 20 nautical miles. This minimum may be reduced to 10 nautical miles if the leading aircraft is traveling at a speed at least 20 knots greater than that of the trailing aircraft. Additionally, when aircraft are expected to pass through the level of another on the same airway during climbing or descending flight, while one aircraft maintains the same level, a minimum separation of 10 nautical miles shall be maintained.

1.2.5 Wake Turbulence Separation

Wake turbulence separation is applied to mitigate the risk posed by vortices generated by heavier aircraft, which can affect the safety of following aircraft. Although wake turbulence is most critical during takeoff and landing phases, en-route separation minima are also established to ensure safe spacing where applicable.

The following wake turbulence separation minima apply in en-route airspace between aircraft of differing weight categories:

Heavy behind Heavy: No additional separation required beyond standard lateral, vertical, or longitudinal minima.
Medium behind Heavy: Minimum 4 NM lateral or longitudinal separation.
Light behind Heavy: Minimum 7 NM lateral or longitudinal separation.
Light behind Medium: Minimum 5 NM lateral or longitudinal separation.

Controllers must apply these minima when vectoring or sequencing aircraft with differing wake turbulence categories in en-route sectors, especially when aircraft are operating on converging or same tracks. If the required wake turbulence separation cannot be assured by lateral or vertical means, longitudinal spacing must be increased accordingly.

1.2.6 Separation in Surveillence Areas

In portions of the Doha FIR where radar surveillance coverage is partial or intermittent, air traffic controllers must apply a combination of radar and procedural separation methods to maintain safe aircraft spacing.

Radar surveillance areas: Controllers apply standard radar separation minima, continuously monitoring aircraft positions via radar displays and updating flight data accordingly.
Transitions between areas: Controllers must carefully coordinate the handover of aircraft between radar control zones. This includes confirming clearances, and ensuring that appropriate separation standards are maintained without gaps.
Controllers must remain vigilant during these transitions to prevent loss of situational awareness and to mitigate the increased workload associated.
Communication with adjacent sectors and pilots is essential to maintain seamless traffic flow and uphold safety standards in mixed surveillance environments.

1.2.7 Exceptions and Reduced Separation

Any exceptions to standard separation minima, including reduced separation, must be authorized only under strict conditions such as contingency operations or specific operational agreements. Controllers must ensure that risk assessments are conducted and that all involved parties are informed.

1.3 Radio & Radar Coverage

1.3.1 Primary Surveillance Radar (PSR)

Primary Surveillance Radar (PSR) detects aircraft by transmitting pulses and receiving reflected signals, allowing identification of aircraft without the need for a transponder. PSR is essential for detecting non-transponder-equipped aircraft and provides a backup layer of surveillance in the event of secondary radar or transponder failures.

Within the Doha FIR, there are three PSR stations each providing coverage extending up to approximately 200 nautical miles. These PSRs primarily serve terminal and low-level enroute traffic around their respective regions.

While PSR does not provide altitude or identification data, it plays a critical role in short-range surveillance and conflict alerting near major airports. Controllers must be aware of PSR limitations, especially at lower altitudes and in areas with terrain masking or clutter.

1.3.2 Monopulse Secondary Surveillance Radar (MSSR)

Monopulse Secondary Surveillance Radar (MSSR) is the primary means of enroute and terminal surveillance in the Doha FIR. It provides highly accurate position, identification, and altitude data by interrogating aircraft transponders (Modes A, C, and S).

The Doha FIR is equipped with four MSSR stations. These stations collectively offer comprehensive coverage across the FIR, with a surveillance range of up to 200 nautical miles from each site, depending on terrain and aircraft altitude.

MSSR data is fully integrated into the TopSky ATM system, supporting automated tagging, conflict detection, and coordination functions. Controllers are responsible for monitoring the accuracy of Mode C/S data and ensuring timely correlation of squawk codes. In the event of radar contact loss or transponder malfunction, fallback procedural separation shall be applied.

1.4 CPDLC/ADS-C Areas

The Doha Flight Information Region (FIR) does not currently have operational Controller–Pilot Data Link Communications (CPDLC) or Automatic Dependent Surveillance–Contract (ADS-C) services in place. However, preparations are underway to support future implementation.

Although CPDLC is not officially active, sector files are configured to support CPDLC-capable aircraft operating above FL295, particularly those equipped with Hoppie ACARS. This configuration is intended to align with the increasing trend of datalink-equipped aircraft and ensures system readiness for eventual integration of CPDLC services.

As of now, ADS-C services are not available within the Doha FIR. Therefore, all aircraft must adhere to traditional voice procedures for position reporting, especially in non-radar or procedural airspace. There are no automatic position reporting systems implemented at this time.

In summary, while CPDLC and ADS-C services are not yet operational, the Doha FIR is technically equipped to accommodate CPDLC-equipped aircraft. Until full implementation.

1.5 Radio Frequency Coverage

All VHF frequencies are managed via sector files and Track Audio configurations, ensuring appropriate frequency allocation for each sector based on traffic volume, geographical coverage, and controller assignment. Controllers must ensure timely transfer of communication, especially near FIR boundaries or in areas with marginal radio performance.

There is no UHF or HF radio coverage simulated on VATSIM for the Doha FIR. All communication is conducted via VHF only, and fallback or relay procedures may be required if communication cannot be established in fringe coverage areas.

Controllers and pilots should be aware of potential communication delays in these zones and apply appropriate separation and coordination procedures accordingly.

1.6 Squawk Code Management

Squawk codes are distributed based on flight type and routing as follows:

Hamad Departure Squawk
2101-2177 3201-3277 1501-1577 Assigned to IFR departures from Doha destined outside the FIR.
Doha FIR Transit Squawk
1501-1577 Applicable for overflights transiting the FIR.
Doha FIR Inbound Squawk
4601-4677 Assigned to inbound flights with destinations within Doha.
Hamad & Doha Domestic Squawk
4601-4677
6501-6577 Assigned to domestic flights entirely within Doha.

1.6.1 Operational Notes

Squawk codes are assigned automatically by the system upon flight plan activation or radar identification.
Controllers must ensure aircraft squawk the correct code and that it correlates with the radar return.
In case of duplicate, garbled, or missing codes, manual reassignment from the appropriate range may be necessary.
Military, VFR, or special-use flights may use codes outside the standard allocation, subject to coordination.

1.7 Enroute Holds

Hold Identifier	Vertical Limits	Inbound Holding Course	Leg Time	Turn Direction
RABLA	FL160 - FL240	190°	1.5	Right
ALTOM	6000FT - FL240	294°	1.5	Right