AREA NAVIGATION ROUTES

GENERAL

The ATS routes are determined in accordance with ICAO Annex 11 and Document 8168.

Heading and distance calculations are based on the following criteria:

• When the difference between the initial and final geographic heading is less than or equal to one degree the average heading is calculated. The average magnetic variation is applied on each segment to obtain the magnetic heading.

• When the difference between the initial and final geographic heading is greater than one degree, the difference is maintained. The initial and final magnetic headings are obtained by applying the corresponding magnetic variation for those points.
  The magnetic variation used is that for 2020.

• Distance is shown in nautical miles and tenths of a mile.

The width of the ATS routes is in accordance with ICAO Annex 11 for VOR-based routes. For those based on NDB, the width of each segment is 5 NM on either side of the centre line for the first 42 NM, diverging to each side with an angle of 6.9° until it reaches its maximum value at the midpoint of the route coverage.

For ATS routes, vertical limits are specified. The lower limit ensures, under International Standard Atmosphere (ISA) conditions, at least 300 m (1000 ft) of vertical separation, or 600 m (2000 ft) in mountainous terrain, above the highest obstacle or the upper limit of restricted areas. The minimum flight altitude/level usable during an IFR flight is 500 ft or 1500 ft above the lower route limit, depending on whether the direction of the route requires odd or even levels, unless otherwise indicated in the remarks box.

Note: All airways shall be considered as RNAV5 (1) from its lower levels, except:

• In FIR/UIR CANARIAS: for airways defined as RNP10.

• When different flight levels or RNAV or RNP navigation specifications are indicated for the airway itself.

(1) In accordance with the ICAO PBN concept (equivalent to B-RNAV). Doc. 9613, AN/937, “Performance-based navigation (PBN) Manual”.

CLASSIFICATION OF ATS ROUTES

Class C: Airways within FIR/UIR BARCELONA, CANARIAS and MADRID between FL145 and FL660.

Note: Airways L660, N728 (segment CABOJ-ARENA), Q279 (segment COSTI-LAY), T975, M660 (segment ROTUM-DKH) are class "F" (with advisory service) between lower limit and FL195.

Class D: Airways whitin FIR BARCELONA, CANARIAS and MADRID between FL095 o MEA and FL145.

Class F: All routes with advisory service.

Note: An ATS route within a higher classification airspace (A, B, C or D) shall adopt the classification of the mentioned airspace.

For airways where ASD: "C/D" is indicated, consideration must be given:

• FL145-FL660 Class C,

• FL095-FL145 Class D.

CONDITIONAL ROUTES (CDR)

See ENR 1.9.