Essa imagem pretende descrever o REIL. REIL são duas luzes piscando sincronizadas. Eles podem ser omnidirecionais ou unidirecionais voltados para a área de abordagem. REIL unidirecional são os preferidos. Mais informações são encontradas em AC 150 / 5340-30.
Os requisitos de instalação estão na seção 7.7.5:
7.7.5 REIL.
7.7.5.1 Location.
Locate and aim the REIL units per Figure A-79.
7.7.5.1.1 When possible, install the two light units equidistant from the runway centerline.
7.7.5.1.2 When location adjustments are necessary, the difference in the distance of the two lights to the runway centerline may not exceed
10 ft (3 m).
7.7.5.1.3 Each light unit must be a minimum of 40 ft (12 m) from the edge of taxiways and other runways.
7.7.5.1.4 The elevation of both units must be within 3 ft (0.9 m) of a horizontal plane through the runway centerline, with the maximum
height above ground limited to 3 ft (0.9 m) (See Figure A-93.)
7.7.5.1.5 When the centerline elevation varies, use the centerline point in line with the two units to measure the centerline elevation.
7.7.5.1.6 Orient the beam axis of an un-baffled unit 15 degrees outward from a line parallel to the runway and inclined at an angle 10 degrees above the horizontal.
7.7.5.1.7 If this standard setting is operationally objectionable, provide optical baffles (per the manufacturer's instructions) and orient the beam axis of the unit 10 degrees outward from a line parallel to the runway centerline and inclined at an angle of 3 degrees above the horizontal.
Conforme descrito aqui, os graus 15 são o alinhamento horizontal e os graus 10 são o alinhamento da elevação.