ENR 1.3  INSTRUMENT FLIGHT RULES

1.3.1.  Rules applicable to all IFR flights

1.3.1.1   Aircraft equipment

Aircraft shall be equipped with suitable instruments and with navigation equipment appropriate to the route to be flown.

1.3.1.2   Minimum levels

Except when necessary for take-off or landing or when specifically authorised by the appropriate authority, an IFR flight shall be flown at a level that is not below the minimum flight altitude established by the State whose territory is over flown, or where no such minimum flight altitude has been established:

1.3.1.2.1 Over high terrain or in mountainous areas, at a level which is at least 600 M (2000 FT) above the highest obstacle located within 8 KM of the estimated position of the aircraft;
1.3.1.2.2 Elsewhere than as specified in 1.3.1.2.1 above, at a level which is at least 300 M (1000 FT) above the highest obstacle located within 8 KM of the estimated position of the aircraft.

Note: The estimated position of the aircraft will take account of the navigational accuracy which can be achieved on the relevant route segment, having regard to the navigational facilities available on the ground and in the aircraft.

1.3.1.3   Change from IFR flight to VFR flight
1.3.1.3.1 An aircraft electing to change the conduct of its flight from compliance with the instrument flight rules to compliance with the visual flight rules shall, if a flight plan was submitted, notify the appropriate air traffic services unit specifically so that the IFR flight can be cancelled and communicate thereto the changes to be made to its current flight plan.
1.3.1.3.2 When an aircraft operating under the instrument flight rules is flown in or encounters visual meteorological conditions, it shall not cancel its IFR flight unless it is anticipated, and intended, that the flight will be continued for a reasonable period of time in uninterrupted visual meteorological conditions.

1.3.2.  Rules applicable to IFR flights within controlled airspace

1.3.2.1 IFR flights shall comply with ICAO Annex 2 paragraph 3.6 to the Convention on International Civil Aviation when operated in controlled airspace.
1.3.2.2 An IFR flight operating in cruising flight in controlled airspace shall be flown at a cruising level, or, if authorised to employ cruise climb techniques, between two levels or above a level, selected from:

  1. The table of cruising levels in ICAO Annex 2 Appendix 3, or

  2. a modified table of cruising levels, when so prescribed in accordance with ICAO Annex 2 Appendix 3 for flight above FL 410,

except that the correlation of levels to track prescribed therein shall not apply whenever otherwise indicated in air traffic control clearances or specified by the appropriate ATS authority in the Aeronautical Information Publication (AIP).

1.3.3.  Rules applicable to IFR flights outside controlled airspace

1.3.3.1   Cruising levels

An IFR flight operating in level cruising flight outside of controlled airspace shall be flown at a cruising level appropriate to its track as specified in:

  1. the table of cruising levels in ICAO Annex 2 Appendix 3, except when otherwise specified by the appropriate ATS authority for flight at or below 900 M (3000 FT); or

  2. a modified table of cruising levels, when so prescribed in accordance with of ICAO Annex 2 Appendix 3 for flight above FL 410.

Note: This provision does not preclude the use of cruise climb techniques by aircraft in supersonic flight.

1.3.3.2   Communications

An IFR flight operating outside controlled airspace but within or into areas, or along routes, designated by the appropriate ATS authority in accordance with ICAO Annex 2 paragraph 3.3.1.2 c) or d) shall maintain a listening watch on the appropriate radio frequency and establish two-way communication, as necessary, with the air traffic services unit providing flight information service.

1.3.3.3   Position reports

An IFR flight operating outside controlled airspace is required by the appropriate ATS authority to:

  1. submit a flight plan, and

  2. maintain a listening watch on the appropriate radio frequency and establish two-way communication, as necessary, with the air traffic services unit providing flight information service, shall report position as specified in ICAO Annex 2 paragraph 3.6.3 for controlled flights.

1.3.4.  Reduced Vertical Separation Minima (RVSM)

1.3.4.1  Area of Application

The airspace within the SAL OCEANIC FIRSAL OCENIC FIR / UIR between FL 290 and FL 410 inclusive, as described in ENR 2.1 is RVSM airspace. Within this airspace, the vertical separation minimum shall be 300 M (1000 FT) between RVSM approved aircraft.

1.3.4.2  Operations within RVSM Airspace

Only aircraft with RVSM approval will be authorised to operate within RVSM airspace.

1.3.4.3  RVSM Approval

RVSM approved aircraft are those that have been approved by the State of Registry or State of the Operator, as appropriate, to conduct flights in RVSM airspace and that are capable of meeting the minimum aircraft system performance specification (MASPS) height - keeping requirements (or equivalent).

1.3.4.4  Wake Turbulence Procedures
1.3.4.4.1 An aircraft operating in RVSM airspace encountering wake turbulence should notify ATC and request a revised clearance. However, in situations where a revised clearance is not possible or practicable:

  1. the pilot should establish contact with other aircraft, if possible, on the appropriate VHF inter - pilot air - to - air frequency, and

  2. one (or both) aircraft may initiate lateral offset(s) not to exceed 2 NM from the assigned route or track provided that:

    1. as soon as practicable, the offsetting aircraft notify ATC that temporary lateral offset action has been taken and specify the reason for doing so, and

    2. the offsetting aircraft notify ATC when re - established on assigned route(s) or track(s).

1.3.4.4.2 ATC will consider suspending RVSM procedures within affected areas of SAL OCEANIC FIRSAL OCENIC FIR / UIR, when there are pilot reports of greater than moderate turbulence. Within areas where RVSM procedures are suspended, the vertical separation minimum between aircraft will be 2000 FT.
1.3.4.5  Mandatory Pilot Reports

Except in the ADS or Radar environment, in addition to reading back altitude assignments, pilots shall report reaching any altitude assigned within RVSM airspace.

1.3.4.6  ACAS

If ACAS (TCAS) is installed in RVSM compliant aircraft, the equipment should be updated to Version 7, or later approved version, for optimum performance in RVSM airspace.

1.3.4.7  Cruising levels
1.3.4.7.1 The cruising levels that will apply within SAL OCEANIC FIRSAL OCENIC FIR / UIR RVSM airspace are those prescribed in Annex 2, Appendix 3, except for ATS routes UN 741 and UN 866 as specified in 1.3.4.7.2.2.
Track from 180° to 359°Track from 000° to 179°
(outside RVSM airspace) 
 FL 410 ------------------------->
<------------------------- FL 400 
 FL 390 ------------------------->
<------------------------- FL 380 
 FL 370 ------------------------->
<------------------------- FL 360 
 FL 350 ------------------------->
<------------------------- FL 340 
 FL 330 ------------------------->
<------------------------- FL 320 
 FL 310 ------------------------->
<------------------------ FL 300 
 FL 290 ------------------------->
 (Outside RVSM airspace)
1.3.4.7.2 In relation with the implementation of the RVSM in the CAR / SAM Regions and with the implementation of a new traffic orientation on ATS Routes UN 741 and UN 866, and in order to avoid flights in opposite directions at the same flight level, a new flight level allocation scheme has been established in the EUR / SAM corridor, as follows:
1.3.4.7.2.1 ATS Routes: UN 873 and UN 857

  1. Southbound traffic: even levels - 400, 380, 360, 340, 320, 300

  2. Northbound traffic: odd levels - 410, 390, 370, 350, 330, 310, 290

1.3.4.7.2.2 ATS routes: UN 741 and UN 866 - Unidirectional Routes

  1. UN 741 - Southbound traffic: even and odd levels to be indistinctly used

  2. UN 866 - Northbound traffic: even and odd levels to be indistinctly used

1.3.4.7.2.3 Operators are requested to plan their flights under this flight level allocation scheme.
1.3.4.8  Random Traffic
1.3.4.8.1 Due to implementation of automatic Data Exchange for Coordination between Sal ACC and Santa Maria ACC, all flights crossing the common FIR boundary Sal Oceanic / Santa Maria and vice versa, are required to do so via the entry / exit compulsory reporting points (i.e. ULTEM, BAMUX, ERNEK, TEGTO, OBOMO, RUKAV, VEPOP and XIBOT), published in both in the Republic of Cabo Verde and Portugal AIP.
1.3.4.8.2 Procedures using entry / exit way points in random area on west of UN 741 into Dakar and Sal ACC‘s border and its mixture with the use of geographical coordinates:

For a better air traffic management by Dakar Oceanic and Sal ACC‘s, all aircraft not equipped with ADS - C / CPDLC, crossing common FIR boundary Dakar Oceanic / Sal Oceanic and vice versa on west of UN 741 shall overfly the entry / exit compulsory reporting points established along that boundary. However, the use of any entry / exit way points, based on geographical coordinates is allowed for ADS - C / CPDLC equipped aircraft. The implementation of these provisions will also help pilots to use most suitable routes.