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AIM

10/12/17

2−1−6

Airport Lighting Aids

To use the system the pilot positions the aircraft so the

elements are in alignment. The glide path indications

are shown in FIG 2−1−8.

2−1−3. Runway End Identifier Lights (REIL)
REILs are installed at many airfields to provide rapid

and positive identification of the approach end of a

particular runway. The system consists of a pair of

synchronized flashing lights located laterally on each

side of the runway threshold. REILs may be either

omnidirectional or unidirectional facing the approach

area. They are effective for:

a. Identification of a runway surrounded by a

preponderance of other lighting.

b. Identification of a runway which lacks contrast

with surrounding terrain.

c. Identification of a runway during reduced

visibility.

2−1−4. Runway Edge Light Systems

a. Runway edge lights are used to outline the

edges of runways during periods of darkness or

restricted visibility conditions. These light systems

are classified according to the intensity or brightness

they are capable of producing: they are the High

Intensity Runway Lights (HIRL), Medium Intensity

Runway Lights (MIRL), and the Low Intensity

Runway Lights (LIRL). The HIRL and MIRL

systems have variable intensity controls, whereas the

LIRLs normally have one intensity setting.

b. The runway edge lights are white, except on

instrument runways yellow replaces white on the last

2,000 feet or half the runway length, whichever is

less, to form a caution zone for landings.

c. The lights marking the ends of the runway emit

red light toward the runway to indicate the end of

runway to a departing aircraft and emit green outward

from the runway end to indicate the threshold to

landing aircraft.

2−1−5. In−runway Lighting

a. Runway Centerline Lighting System

(RCLS). Runway centerline lights are installed on

some precision approach runways to facilitate

landing under adverse visibility conditions. They are

located along the runway centerline and are spaced at

50−foot intervals. When viewed from the landing

threshold, the runway centerline lights are white until

the last 3,000 feet of the runway. The white lights

begin to alternate with red for the next 2,000 feet, and

for the last 1,000 feet of the runway, all centerline

lights are red.

b. Touchdown Zone Lights (TDZL). Touch-

down zone lights are installed on some precision

approach runways to indicate the touchdown zone

when landing under adverse visibility conditions.

They consist of two rows of transverse light bars

disposed symmetrically about the runway centerline.

The system consists of steady−burning white lights

which start 100 feet beyond the landing threshold and

extend to 3,000 feet beyond the landing threshold or

to the midpoint of the runway, whichever is less.

c. Taxiway Centerline Lead−Off Lights. Taxi-

way centerline lead−off lights provide visual

guidance to persons exiting the runway. They are

color−coded to warn pilots and vehicle drivers that

they are within the runway environment or

instrument landing system (ILS) critical area,

whichever is more restrictive. Alternate green and

yellow lights are installed, beginning with green,

from the runway centerline to one centerline light

position beyond the runway holding position or ILS

critical area holding position.

d. Taxiway Centerline Lead−On Lights. Taxi-

way centerline lead−on lights provide visual

guidance to persons entering the runway. These

“lead−on” lights are also color−coded with the same

color pattern as lead−off lights to warn pilots and

vehicle drivers that they are within the runway

environment or instrument landing system (ILS)

critical area, whichever is more conservative. The

fixtures used for lead−on lights are bidirectional, i.e.,

one side emits light for the lead−on function while the

other side emits light for the lead−off function. Any

fixture that emits yellow light for the lead−off

function must also emit yellow light for the lead−on

function. (See FIG 2−1−14.)

e. Land and Hold Short Lights. Land and hold

short lights are used to indicate the hold short point on

certain runways which are approved for Land and

Hold Short Operations (LAHSO). Land and hold

short lights consist of a row of pulsing white lights

installed across the runway at the hold short point.

Where installed, the lights will be on anytime

LAHSO is in effect. These lights will be off when

LAHSO is not in effect.