ENR 1.6 ATS SURVEILLANCE SERVICES AND PROCEDURES

1. GENERAL

1.1 Radar units are operated as an integral part of the parent ATS unit and provide radar service to aircraft to the maximum practicable extent, to meet the operational requirements. Factors, such as radar coverage, controller workload and equipment capabilities, affect these services, and the radar controller will determine whether he can provide, or continue to provide, radar services in any specific case.

1.2 Pilots will be advised on commencement and termination of radar services.

2. RADAR COVERAGE

Total radar coverage within the Muscat FIR.


Oman Primary Radars
Location	Type	Max Range (NM)
Muscat	PSR	100
Salalah	PSR	100


Oman Secondary Radars
Location	Type	Max Range (NM)
Muscat	MSSR	250
Wudam
Ras Al-Had
Jalaan
Al-Duqm
Qairoon Hiriti
Salalah

3. APPLICATION OF RADAR CONTROL SERVICE

3.1 Radar identification is achieved to provisions specified by ICAO.

3.2 Radar control services are provided in all controlled airspace. This service may include:

a) radar separation of arriving, departing and en route traffic;

b) radar monitoring of arriving, departing and en route traffic to provide information on any significant deviation from the normal flight path;

c) radar vectoring when required;

d) assistance to aircraft in an emergency;

e) assistance to aircraft crossing controlled airspace;

f) warnings and position information on other aircraft considered constituting a hazard;

g) information to assist in the navigation of aircraft;

h) information on observed weather.

3.3 The minimum horizontal radar separations are:

a) 5 NM en route;

b) 5 NM within Muscat CTR andTMA;

c) 5 NM within Salalah CTR and TMA;

These minimum horizontal radar separation values may be increased:

a) at the controller's discretion;

b) when wake turbulence is known;

c) at the request of the pilot.

3.4 Levels assigned by the radar controller to pilots will provide a minimum terrain clearance according to the phase of flight.

4. SECONDARY SURVEILLANCE RADAR (SSR)

4.1 Operating procedures

4.1.1 Except as provided below, pilots will operate transponders and select modes and codes according to ATC instructions. In particular, when entering the Muscat FIR, pilots who have already received specific instructions from ATC concerning the setting of the transponder, will maintain that setting until otherwise instructed. Mode C will be selected at all times unless otherwise instructed or in exceptional cases as stated below.

4.1.2 Pilots of aircraft operating in or about to enter the Muscat FIR who have not received specific instructions from ATC concerning the setting of the transponder, will operate the transponder on mode A/3 code 2000 and maintain that code setting unless otherwise instructed.

4.1.3 Mode C will be selected at all times unless otherwise instructed.

4.1.4 System of SSR Code Assignment

a) Muscat uses code blocks assigned under the originating region code allocation method. (ORCAM)

b) Aircraft entering the Muscat FIR shall retain the SSR code previously issued by ATC in an adjacent FIR (except for flights from Mumbai, Karachi and Sanaa FIR).

c) The following Transit SSR codes (Mode A) will be assigned by Muscat ACC for flights entering Muscat from Mumbai, Karachi and Sanaa FIR and flights departing Oman airports intending to leave Muscat FIR: 3500 to 3577, 4000 to 4077, 4700 to 4777.

d) The following Domestic SSR codes (Mode A) will be assigned by Muscat ACC for flights remaining within the Muscat FIR:1200 to 1277, 4600 to 4677.

4.2 Emergency procedures

4.2.1 If the pilot of an aircraft encountering a state of emergency has previously been directed by ATC to operate the transponder on a specific code, this code setting will be maintained until otherwise advised. In all other emergency circumstances, the transponder will be set as follows:

a) Mode A/3 code 7500 - Unlawful interference.

b) Mode A/3 code 7600 - Radio communication failure.

c) Mode A/3 code 7700 - Other states of emergency.

4.2.2 Notwithstanding the procedure in paragraph 4.1.1 above, a pilot may select mode A/3 code 7500, 7600 or 7700, as appropriate, whenever the nature of emergency is such that this appears to him to be the most suitable course of action.

5. RADAR AND RADIO FAILURE PROCEDURES

5.1 Radar Failure

In case 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.

5.2 Radio Failure

5.2.1 Aircraft not equipped with transponder

The radar controller will establish whether the aircraft radio receiver is working by instructing the pilot to perform a turn, maintain the new heading for a period of time (specified) and then resume normal navigation. The magnitude of the turn will be such as to enable the identification to be achieved should the aircraft not previously have been identified. The direction of the turn will be determined by the operational requirements.

5.2.2 Aircraft equipped with transponder

The radar controller will establish whether the aircraft radio receiver is working by instructing the pilot to perform one or more of the following:

a) change transponder mode,

b) change transponder code,

c) operate the SPI feature.

The method used will be such as to enable the identification to be achieved should the aircraft not previously have been identified.

5.2.3 Action by radar control

a) If subsequent movement of the radar echo or subsequent radar responses indicate that the aircraft radio receiver is working, the radar controller will assume or resume radar control, as the case may be, and continue to pass instructions as for a normal radar service.

b) If subsequent movements of the radar echo or subsequent radar responses indicate that the aircraft radio receiver is not working, the radar controller will take action, according to the circumstances prevailing, as detailed in paragraph 5.2.3.c) and d) below as appropriate.

c) If, prior to the communication failure, the radio failure aircraft was identified, the radar controller will ensure that all known traffic is provided with a minimum of 5 NM horizontal radar separation from the radio failure aircraft, performing identification as necessary, until such time as the radio failure leaves radar coverage or lands.

d) If, prior to the communication failure, the radio failure aircraft was not identified or its position is not known, the radar controller will continue to provide a radar service to the identified aircraft only, provided that primary radar coverage is sufficient for him to ensure a minimum of 5 NM horizontal radar separation from all unknown traffic, until such time as the radio failure aircraft is known to have left the area or landed.

5.2.4 Action by aircraft

a) Aircraft able to receive transmissions from radar control will comply with such instructions as are issued, acknowledging as indicated by the radar controller, as detailed in paragraph 5.2.3 a) above.

b) Aircraft not able to receive transmissions will comply with the ICAO radio communication failure procedures as prescribed in Annex 2, 3.6.5.2 and PANS-ATM Chapter 15.2 and those detailed in: AD 2.OOMS section 22 for Muscat and AD 2.OOSA section 22 for Salalah.

c) It is essential that the procedures as detailed above, as appropriate, are rigidly adhered to as the action by radar control, detailed above, are based upon aircraft compliance therewith; failure to comply may result in loss of separation.

5.2.5 Action in the event of air-ground communication failure

As soon as it is known that two-way communications has failed, ATC shall maintain separation between the aircraft having the communication failure and other aircraft based on the assumption that the aircraft will operate in accordance with 5.2.6 and 5.2.7.

Note: The following expands upon the requirements contained in Annex 2, 3.6.5.2 and the PANSATM, 8.8.3 and 15.2 and specifies additional details regarding air-ground communications failure.

5.2.6 Visual meteorological condition (VMC)

Except as provided in 5.2.7, a controlled flight experiencing communications failure in VMC shall:

a) set transponder to code 7600;

b) continue to fly in VMC;

c) land at the nearest suitable aerodrome; and

d) report its arrival time by the most expeditious means to the appropriate air traffic control unit.

5.2.7 Instrument meteorological conditions (IMC)

A controlled IFR flight experiencing communications failure in IMC or in VMC when it does not appear feasible to continue in VMC within the Muscat FIR shall:

a) set transponder to code 7600; and

b) maintain the last assigned speed and level or the minimum flight altitude, if the minimum flight altitude is higher than the last assigned level, for a period of 7 minutes.
The period 7 minutes commences:

1) if operating on a route without compulsory reporting points or has been instructed to omit position

report:

a) at the time the last assigned level or minimum flight altitude is reached, or

b) at the time the aircraft sets transponder to code 7600,

whichever is later; or

2) if operating on a route with compulsory reporting points and no instructions to omit position reports has been received:

a) at the time the last assigned level or minimum flight altitude is reached, or

b) at the previously reported pilot estimate for the compulsory reporting point, or

c) at the time the aircraft fails to report its position over a compulsory reporting point,
whichever is later, or

c) thereafter, adjust level and speed in accordance with the filed flight plan;

Note: With regard to changes to levels and speed, the filed flight plan, which is the flight plan as filed with an ATS unit by the pilot or designated representative without any subsequent changes, will be used.

d) if being radar vectored or proceeding offset according to RNAV without a specified limit, 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;

Note: With regard to the route to be flown or the time to begin descent to the arrival aerodrome, the current flight plan, which is the flight plan, including changes, if any, brought by subsequent clearances, will be used.

e) proceed according to the current flight plan to the appropriate designated navigation aid serving the destination aerodrome and, when required to ensure compliance with 5.2.7 f), hold over this aid until commencement of decent;

f) commence descent from the navigation aid specified in 5.2.7 e) at, or as close as possible to, the expected approach time last received and acknowledged or, if no expected approach time has been received and acknowledged, at, or as close as possible to, the estimated time of arrival resulting from the current flight plan;

g) complete a normal instrument approach procedure as specified for the designated navigation aid; and

h) land, if possible, within thirty minutes after the estimated time of arrival specified in 5.2.7 f) or the last acknowledged expected approach time, which ever is later.

Note: Pilots are reminded that the aircraft may not be in an area of secondary surveillance radar coverage.