# The Air Navigation (General) Regulations 1993, Regulation 18: Minimum navigation performance specifications—prescribed airspace and navigation performance capability


(1) For the purposes of article 39(1)(a), the following navigation performance capability is hereby prescribed, that is to say, a capability to ensure that:—
(a) the standard deviation of lateral errors in the track of the aircraft is not more than 6.3 nautical miles; and
(b) the proportion of the flight time of the aircraft during which the actual track of the aircraft is 30 nautical miles or more off the track along which it has been given an air traffic control clearance to fly is less than 5.3 × 10−4 and
(c) the proportion of the flight time of the aircraft during which the actual track of the aircraft is between 50 and 70 nautical miles off the track along which it has been given an air traffic control clearance to fly is less than 13 × 10−5.
(2) For the purposes of article 39(1), the following airspace is hereby prescribed, that is to say, the airspace from flight level 275 to flight level 400 within the area defined by rhumb lines joining successively the following points—
N3410.00
W01748.00
N3630.00
W01500.00
N4200.00
W01500.00
N4300.00
W01300.00
N4500.00
W01300.00
N4500.00
W00800.00
N5100.00
W00800.00
N5100.00
W01500.00
N5400.00
W01500.00
N5434.00
W01000.00
N6100.00
W01000.00
N6100.00
00000.00
N8200.00
00000.00
N8200.00
E03000.00
North Pole
N8200.00
W06000.00
N7800.00
W07500.00
N7600.00
W07600.00
N6500.00
W05745.00
N6500.00
W06000.00
N6400.00
W06300.00
N6100.00
W06300.00
N5700.00
W05900.00
N5300.00
W05400.00
N4900.00
W05100.00
N4500.00
W05100.00
N4500.00
W05300.00
N4336.00
W06000.00
N4152.00
W06700.00
N3900.00
W06700.00
N3835.00
W06853.00
N3830.00
W06915.00
N3830.00
W06000.00
N2700.00
W06000.00
N2700.00
W02500.00
N3000.00
W02500.00
N3000.00
W02000.00
N3139.00
W01725.00
thence by that part of the arc of a circle radius 100 nautical miles centered on N3304.00 W01621.00 to N3410.00 W01748.00.

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Source: https://www.legislation.gov.uk/uksi/1993/1622/regulation/18 (the official version)
Page: https://openlegislation.uk/air-navigation-general-regulations-1993/regulation-18
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.