Attachment 14
you must ensure wingtip clearance shown in Table 6.1 is provided. Some examples of these
type facilities are hangars, aircraft sunshades, wash racks, taxi-through alert shelters, air
passenger terminals, movable passenger access platforms (jetways), base operations facilities,
squadron operations facilities, airfield maintenance unit facilities, fire stations, fuel or
groundwater recovery systems, material handling equipment storage facilities, airfreight
terminals, and weather shelters for sentries.
A14.2.20.3.5. Utility Access Points. Utility handholes and manholes should be constructed
flush with grade. These utility access points do not require waiver if the drop-off at the edge of
the foundation is 76 millimeters (3 inches) or less.
A14.2.20.3.6. Automated Weather Observing Systems (Non-Frangible). An automated
weather observing system consists of a suite of weather sensors and processor(s) capable of
collecting, measuring and reporting the following parameters: wind speed and direction,
temperature and dew point, visibility, cloud height, present weather, precipitation amount,
lightning detection, and freezing rain. A notional primary sensor group will contain winds,
cloud height, visibility, temperature & dewpoint, liquid precipitation accumulation, freezing
rain occurrence, precipitation identification, barometer (triple redundancy), and lightning
sensors. This sensor group will be installed on a foundation 40 feet long three feet wide and
three feet deep, placed flush with grade. The primary sensor group and cabinets will be 40 feet
long, 20 feet wide, 37 feet tall and weighs approximately 4500 pounds. At the alternate end of
the runway there will be a discontinuity sensor group that contains only a cabinet, winds, cloud
height, and visibility sensors. This discontinuity sensor group will be installed on a foundation
20 feet long three feet wide and three feet deep, placed flush with grade. The sensor group will
be 13 feet high and five feet wide and weighs approximately 1500 pounds. Special care is
necessary in selecting appropriate locations for installation of sensors to assure that the
resultant observations are representative of the meteorological conditions affecting aviation
operations. The primary sensor group and the discontinuity group must be located
approximately 500 feet (150 meters) from centerline of the runway and approximately 750 feet
(230 meters) to 1,000 feet (300 meters) of the designated runway threshold. The sensor array
should be parallel to the runway with the closest sensor 500 feet from the centerline. Siting of
sensors more than 500 feet (150 meters) from centerline of the runway provides data less
representative of the runway and therefore could have a negative affect on aviation operations.
Automated Weather Observing Systems are not frangible. However, equipment will be
mounted on concrete footings or foundations with no concrete edges above ground level.
Equipment is mounted on supports with a designed break point no higher than 3 inches above
grade. Weather equipment must be adequately supported to be stable during high winds and be
able to support system, ice and wind loads. These severe conditions are the very weather
elements that the automated weather observing systems are supposed to measure and provide
data for safety of flight. The equipment mountings will be designed to support the desired
equipment load to eliminate vibration and swaying which can result in erroneous readings.
A14.2.20.3.7. Air Traffic Control Towers may be considered permissible deviations to the
Transitional Surface if it meets the siting criteria given in Attachment 18.
A14-12
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