# The Air Navigation (Overseas Territories) Order 2013, Paragraph 34: ... semi-circular rule

Extent: E+W+S+N.I.

(1) Subject to paragraphs (2) and (3), an aircraft in level flight above 3,000 feet above mean sea level or above the appropriate transition altitude, whichever is the higher, must be flown at a level appropriate to its magnetic track, in accordance with Table 1 ....
(2) For the purposes of paragraph (1), the level of flight must be measured by an altimeter set—
(a) in the case of a flight over the Territory, to a pressure setting of 1013.2 hectopascals; or
(b) in the case of any other flight, according to the system published by the competent authority in relation to the area over which the aircraft is flying.
(3) An aircraft may be flown at a level other than the level required by paragraph (1) if it flies—
(a) in conformity with instructions given by an air traffic control unit;
(b) in accordance with notified en-route holding patterns; or
(c) in accordance with holding procedures notified in relation to an aerodrome.
(4) For the purposes of this rule “transition altitude” means the altitude which is notified in relation to flights over notified areas.
Table 1
Semi-circular rule
Track
From 000 degrees to 179 degrees
From 180 degrees to 359 degrees
IFR flights
VFR flights
IFR flights
VFR flights
Level
Level
Level
Level
FL
Feet
Metres
FL
Feet
Metres
FL
Feet
Metres
FL
Feet
Metres
010
1,000
300
-
-
-
020
2,000
600
-
-
-
030
3,000
900
035
3,500
1,050
040
4,000
1.200
045
4,500
1,350
050
5,000
1,500
055
5,500
1,700
060
6,000
1,850
065
6,500
2,000
070
7,000
2,150
075
7,500
2,300
080
8,000
2,450
085
8,500
2,600
090
9,000
2,750
095
9,500
2,900
100
10,000
3,050
105
10,500
3,200
110
11,000
3,350
115
11,500
3,350
120
12,000
3,650
125
12,500
3,800
130
13,000
3,950
135
13,500
4,100
140
14,000
4,250
145
14,500
4,400
150
15,000
4,550
155
15,500
4,700
160
16,000
4,900
165
16,500
5,050
170
17,000
5,200
175
17,500
5,350
180
18,000
5,500
185
18,500
5,650
190
19,000
5,800
195
19,500
5,950
200
20,000
6,100
205
20,500
6,250
210
21,000
6,400
215
21,500
6,550
220
22,000
6,700
225
22,500
6,850
230
23,000
7,000
235
23,500
7,150
240
24,000
7,300
245
24,500
7,450
250
25,000
7,600
255
25,500
7,750
260
26,000
7,900
265
26,500
8,100
270
27,000
8,250
275
27,500
8,400
280
28,000
8,550
285
28,500
8,700
290
29,000
8,850
300
30,000
9,150
310
31,000
9,450
320
32,000
9,750
330
33,000
10,050
340
34,000
10,350
350
35,000
10,650
360
36,000
10,950
370
37,000
11,300
380
38,000
11,600
390
39,000
11,900
400
40,000
12,200
410
41,000
12,500
430
43,000
13,100
450
45,000
13,700
470
47,000
14,350
490
49,000
14,950
510
51,000
15,500
etc.
etc.
etc.
etc.
etc.
etc.

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Source: https://www.legislation.gov.uk/uksi/2013/2870/schedule/4/paragraph/34 (the official version)
Page: https://openlegislation.uk/air-navigation-overseas-territories-order-2013/schedule-4/paragraph-34
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.