• Direction signs—yellow background with black  inscription. The inscription identifies the designation  of the intersecting taxiway(s) leading out of an  intersection.  • Destination signs—yellow background with black  inscription and arrows. These signs provide information  on locating areas, such as runways, terminals, cargo  areas, and civil aviation areas.  • Information signs—yellow background with black  inscription. These signs are used to provide the pilot  with information on areas that cannot be seen from the  control tower, applicable radio frequencies, and noise  abatement procedures. The airport operator determines  the need, size, and location of these signs.  • Runway distance remaining signs—black background  with white numbers. The numbers indicate the  distance of the remaining runway in thousands of feet.  The majority of airports have some type of lighting for night  operations. The variety and type of lighting systems depends  on the volume and complexity of operations at a given airport.  Airport lighting is standardized so that airports use the same  light colors for runways and taxiways.  Airport beacons help a pilot identify an airport at night.  The beacons are normally operated from dusk until dawn.  Sometimes they are turned on if the ceiling is less than 1,000  feet and/or the ground visibility is less than 3 statute miles (VFR  minimums). However, there is no requirement for this, so a  pilot has the responsibility of determining if the weather meets  VFR requirements. The beacon has a vertical light distribution  to make it most effective from 1–10° above the horizon,  although it can be seen well above or below this spread. The  beacon may be an omnidirectional capacitor-discharge device,  or it may rotate at a constant speed, that produces the visual  effect of flashes at regular intervals. The combination of light  colors from an airport beacon indicates the type of airport.  [Figure 14-28]  Some of the most common beacons are:  Approach light systems are primarily intended to provide a  means to transition from instrument flight to visual flight for  landing. The system configuration depends on whether the  A precision approach path indicator (PAPI) uses lights similar  to the VASI system, except they are installed in a single row,  normally on the left side of the runway.  [Figure 14-30]  The basic principle of the VASI is that of color differentiation  between red and white. Each light unit projects a beam of  light, a white segment in the upper part of the beam and a  red segment in the lower part of the beam. The lights are  arranged so the pilot sees the combination of lights shown in  Figure 14-29  to indicate below, on, or above the glidepath.  runway is a precision or nonprecision instrument runway.  Some systems include sequenced flashing lights that appear  to the pilot as a ball of light traveling toward the runway at  high speed. Approach lights can also aid pilots operating  under VFR at night.  Visual glideslope indicators provide the pilot with glidepath  information that can be used for day or night approaches. By  maintaining the proper glidepath as provided by the system,  a pilot should have adequate obstacle clearance and should  touch down within a specified portion of the runway.  VASI installations are the most common visual glidepath  systems in use. The VASI provides obstruction clearance  within 10° of the extended runway centerline and up to four  nautical miles (NM) from the runway threshold.  The VASI consists of light units arranged in bars. There are  2-bar and 3-bar VASIs. The 2-bar VASI has near and far light  bars and the 3-bar VASI has near, middle, and far light bars.  Two-bar VASI installations provide one visual glidepath  that is normally set at 3°. The 3-bar system provides two  glidepaths, the lower glidepath normally set at 3° and the  upper glidepath ¼ degree above the lower glidepath.  Airport Lighting  Airport Beacon  Visual Glideslope Indicators  Visual Approach Slope Indicator (VASI)  Other Glidepath Systems  Approach Light Systems  Figure 14-28.  Airport rotating beacons.  • Flashing white and green for civilian land airports  • Flashing white and yellow for a water airport  • Flashing white, yellow, and green for a heliport  • Two quick white flashes alternating with a green flash  identifying a military airport  White  White  Yellow Green  14-16 