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AA assembly area

AABNCP advanced airborne control platform

AAFIF Automated Airfield Information File

AASHO American Association of State Highway Officials

AASHTO American Association of State Highway and Transportation Officials

ABC all-bituminous pavement

ABS acrylonitrile-butadiene-styrene (plastic)

A/C aircraft

AC asphalt cement or asphaltic cement

ACC asphalt-cement concrete

ACE armored combat earthmover

ACN aircraft classification number

ADEPT alternating door exit procedures for training

adj adjusted

ADR air base damage repair

AF Air Force

AFB Air Force Base

AFCESA Air Force Civil Engineering Support Agency

AFCS Army Facilities Components System

AFESC Air Force Engineering and Services Center

AFI Air Force Instruction

AFM or AFMAN Air Force manual

AFP or AFPAM Air Force pamphlet

AFR Air Force regulation

AFWL-TR Air Force Weapons Laboratory Technical Report

agg aggregate

AGL above ground level

AH attack helicopter

AHD average haul distance

AI airfield index

air base
An airfield having, in addition to operational facilities, shelter for personnel and facilities for supply and repair of aircraft.

An area prepared for the accommodation (including any buildings, installations, and equipment), landing, and takeoff of aircraft.

AM-2 aluminum matting

AMC Air Mobility Command

AML airfield marking and lighting

ammo ammunition

ammunition and explosives storage area
An accessible and defiladed area having good cover; located at a safe distance from troops, aircraft, and other facilities; and used for storing explosives and ammunition.

ancillary items
Components of the mat system for use with the basic mat to construct the runway and taxiway complex, to replace damaged mat, or to remove mat for repair of the subgrade. The ancillary items are type-classified into a mat set to simplify requisitioning.

ANG Air National Guard

angle, glide
A small vertical angle measured outward and upward from the end of the flight strip, above which no obstruction should extend within the area of the approach zone. It also indicates the safe descent angle for various types of aircraft and is expressed as a ratio such as 35:1.

antiskid coating

A compound applied to the top surface of a landing mat during fabrication to provide a skid-resistant surface, especially during inclement weather.

AP antipersonnel

APC armored personnel carrier

approach zone
A trapezoidal area extending outward from each end of a flight strip, within which no natural or man-made object may project above the glide angle.

apron, cargo
A prepared area for loading and unloading personnel and cargo.

apron, maintenance
A prepared area for parking aircraft while being serviced or repaired.

apron, parking
A prepared area used in place of hardstands for the parking of aircraft. It is also referred to as a conventional apron.

apron, warm-up

A stabilized or surfaced area used for the assembly or warming up of aircraft, usually located at both ends of the runway adjacent to and with the long axis parallel to the connecting taxiway.

approx approximately

Apr April

APSB asphalt penetrative soil binder

AR Army regulation

ARIA advanced range instrumentation aircraft

ASCE American Society of Civil Engineers

ASTM American Society of Testing and Materials

ATC air traffic control

atk attack

Atterberg Limits
Soil plasticity test used to measure soil cohesiveness; that is, cohesive or cohesionless.

ATTN attention

Aug August

AUTOCAD automated computer-aided drafting and design

av absolute volume

average daily traffic (ADT)
The anticipated average number of vehicle per day that will use a completed facility.

average running speed
The speed expected to be maintained by most vehicles. It is equal to the total traveled distance divided by total time consumed.

 avg average

AVIM aviation intermediate maintenance

avn aviation

AWACS Airborne Warning and Control System

AWADS Adverse Weather Aerial Delivery System

AWS Air Weather Service

banked cubic yardage (BCY)
Soil measured in its natural state.

base course or base
Base course consists of well-graded, granular materials that have a liquid limit less than 25 percent and a plastic limit less than 5 percent. The base course is the most important element in a road structure. It functions as the primary load-bearing component of the road, ultimately providing the pavement (or surface) strength. Therefore, it is made of higher quality material than subbase material.

bbl barrel

bde brigade

bearing capacity
The ability of a soil to support a vehicle without undue sinkage of the vehicle.

Terracing on a slope.

A raised lip, usually of earth, placed at the top edge of a channel to prevent flow into the channel at places not protected against erosion.

bitumen or bituminous
The most common type of asphalt surface placed in the theater of operations.

bn battalion

BOM bill of materials

borrow pit
An excavated area where material has been dug for use as fill at another location.

BTU British thermal unit

BVM Bays Village of Maryland

C, CL, or C/L centerline

C Celsius

C cut

C confidential

CAD computer-aided design

cal caliber

California Bearing Ratio (CBR)
A measure of the bearing capacity of a soil based upon its shearing resistance. CBR is expressed as a percentage of the unit load required to force a piston into the soil divided by the unit load required to force the same piston the same depth into a standard sample of crushed stone. See Chapter 5, FM 5-430-00-1/AFPAM 32-8013, Vol 1, or FM 5-541.

CAMMS Condensed Army Mobility Modeling System

CAPES Controlled Alternate Parachute Exit System

CARP computed air release point

cav cavalry

CBA close battle area

cbt combat

C/C center to center

CCT combat control team

cdr commander

CDS container delivery system

CE 55
Laboratory compactive effort (CE) accomplished by the impact of 55 hammer blows per layer.

CES civil engineering squadron

CEV combat engineer vehicle

cf cubic feet

cfs cubic feet per second

CG center of gravity

CH inorganic clays of high plasticity, fat clays

CH cargo helicopter

CI cone index

CL clays, low compressibility (LL< 50)

clear area
A rectangular area located adjacent to and outside of the runway shoulders, in which tree stumps are cut close to the ground, boulders removed, and the general area roughly graded to the extent necessary to reduce damage to aircraft in the event of erratic performance in which the aircraft runs off the runway.

cm centimeter

cmd command

CMP corrugated metal pipe

cm/sec centimeters per second

co company

coarse-grained soil
A free-draining soil of which more than 50 percent by weight of the grains will be retained on a No. 200 sieve. For trafficability purposes, these are dry beach and desert soils usually containing less than 7 percent of material passing the No. 200 sieve. Gravels are not considered to pose a trafficability problem.

comm communications

COMMZ communications zone

comp compacted

compacted cubic yards (CCY)
A measurement of compacted soil.

Process of mechanically densifying a soil, normally by the application of a moving (or dynamic) load.

compactive effort (CE)
Method used to compact the soil.

cone index (CI)
An index of the shearing resistance of soil. The CI is obtained with a cone penetrometer. The number represents resistance to penetration into the soil of the 30-degree cone with a 1/2-square inch base area (actual load in pounds on cone base area in square inches), using a dial calibrated to produce an index of 300 when 150 lb of pressure are exerted on the handle. The CI reading is normally taken at the 0-inch (base of the cone) and at every 3-inch interval down to 18 inches or until the dial reaches the maximum of 300. A number of tests will be taken and each specified interval reading will be averaged. That average becomes the CI for the inch level.

const construction

cont continue

control tower
Usually a covered and enclosed platform for the direction and control of traffic. Depending upon the type of construction authorized, the control tower may be a mobile unit or a selfsupported structure, no higher than necessary to afford an unobstructed view of the entire flight path and taxiways.

CONUS continental United States

CPM critical path method

CPT captain

critical layer
The soil layer that determines the rating cone index (for finegrained soil) or cone index (for coarse-grained soil) of the area considered. Its depth varies with the soil profile and the weight and type of vehicle. Generally, the critical layer for fine-grained soils is 6 to 12 inches below the surface when subjected to passes of a vehicle. For coarse-grained soils, the critical layer is usually from the surface to a 6-inch depth for all vehicular passes.

(1) The difference in elevation between the centerline and the surface edge. The crown expedites surface-water runoff on the road. The amount of crown depends on the surface used. Surfaces such as concrete or bituminous materials require little crown because of their impermeability, but permeable surfaces such as earth or gravel require a large crown. (2) The outside top of the culvert.

CRS Central Radar System

CSS cationic slow setting

cu cubic

cm centimeter

CUCV commercial utility cargo vehicle

cu ft cubic foot/feet

An enclosed waterway used to pass water through a structure consisting of an embankment or fill.

cut or cutting
That portion of through construction produced by the removal of the natural formation of earth or rock, whether sloped or level. The terms sidehill cut and through-hill cut describe the resulting cross sections commonly encountered.

cut slope
The slope from the top of a cut to the ditch line (bottom of ditch). Sometimes it is called the back slope.

cu yd or cy cubic yard(s)

D depth

DA Department of the Army

DBH diameter at breast height

DCA dust-control agent

DCP dynamic cone penetrometer

DD Department of Defense

Dec December

deg degree(s)

dept department

design hourly volume (DHV)
The number of vehicles that a road may typically be expected to accommodate in an hour. The DHV is 15 percent of the ADT.

design speed
The speed for which a facility is designed. Pertinent geometric features, such as horizontal curves and grades, may be based on design speed.

design storm
The storm of greatest intensity for a given period. For example, a 2-year design storm is a storm expected to be equalled once in 2 years.

The storage of water in depressions in the earth's surface.

DF direction finder

dH pressure altitude

dia diameter

A paved ford used for crossing dry, wide, shallow arroyos or washes in semi-arid regions subject to flash floods.

ditch slope
The slope of the ditch extending from the outside edge of the shoulder to the bottom of the ditch. This slope should be relatively flat to avoid damage to vehicles driven into the ditch and to permit easy recovery.

diversion ditch
A ditch used to transport water away from roadways or airfields.

DMA Defense Mapping Agency

DMZ demilitarized zone

DOD Department of Defense

A structure that absorbs the impact energy of water as it falls vertically to a lower level waterway.

DSA division support area

DSN Defense Switched Network

DT ditch time

DZ drop zone

DZC drop zone control

E east

ea each

earth anchors
A device used along the sides and ends of the matting to hold the mat in position. Power equipment can be used in driving the anchors. The pneumatic wood-boring drill and posthole digger have both proven effective in this. The average pull required to remove anchors after emplacement is 2,040 pounds.

EL or elev elevation

EM engineer manual

EM enlisted member

ENE east northeast

engr engineer

EOD explosive ordnance disposal

EPW enemy prisoner of war

The transportation of weathered materials by wind or water.

ESE east southeast

ETAC Environmental Technical Applications Center

EW east-west

EZ extraction zone

EZC extraction zone control

F fill

F Fahrenheit

FAA Federal Aviation Authority

FC field circular

Feb February

fill or filling
Material used to fill a receptacle, cavity, passage, or low place. Using material to fill a cavity or low place.

fill slope
The incline extending from the outside edge of the shoulder to the toe (bottom) of a fill.
fine-grained soil A silt or clay soil of which more than 50 percent by weight of the grains will pass a No. 200 sieve (smaller than 0.074 millimeter in diameter).

A U-shaped revetment, normally of earth, and hardstand for boresiting aircraft armament and test firing.

fld field

flight path
The line connecting successive positions occupied by an aircraft, missile, or space vehicle as it moves through air or space.

flight strip
Includes area of the runway, shoulders, clear area, overruns, and clear zones.

FM field manual

A shallow place in a waterway where the bottom permits the passage of personnel and vehicles.

fpm foot (feet) per minute

fps foot (feet) per second

frost action
Processes which affect the ability of soil to support a structure when accumulated water in the form of ice lenses in the soil is subjected to natural freezing conditions.

frost-susceptible soil
Soil in which significant ice segregation will occur when the necessary moisture and freezing conditions are present.

FSN federal stock number

ft foot/feet

FT Fort

ft/ft feet per foot

ft/in feet per inch

FTR fighter

ft2/yd2 square feet per square yard

fuel storage area
An accessible area, having good cover, located a safe distance from troops, aircraft, and other facilities, and used for the storage and dispensing of aviation fuels.

G gravel

G-1 Assistant Chief of Staff, G-1(Personnel)

Large, steel wire-mesh baskets filled with stones, usually rectangular in shape and variable in size. They are designed to solve the problem of erosion.

gal gallon(s)

gal/yd gallon(s) per square yard

gal/lb gallon(s) per pound

GC clayey gravels, gravel-sand-clay mixture

GCA ground-controlled approach

geometric design (geometry or geometric features)
Refers to all visible features of the road such as lane width, shoulder width, and alignment.

GLE grade-line elevation

gm gram(s)

silty gravels, gravel-sand-silt mixture

GMRS Ground Mark Release System

poorly graded gravels or gravel-sand mixture, little or no fines

To level off to a smooth horizontal or sloping surface.

ground icing
An icing whose source of water is from groundwater flow above permafrost.

groundwater table
The upper limit of the saturated zone of free water.

A mixture of cement, sand, and water sprayed from a high-pressure nozzle onto a surface to protect it.

well-graded gravels, gravel-sand mixture, little or no fines

H height

HAARS High-Altitude Airdrop Resupply System

A paved or stabilized area where vehicles are parked. Open ground area having a prepared surface and used for the storage of material.

hel helicopter

HM heavy mat

HMMWV high mobility, multipurpose wheeled vehicle

HP high point

HQ headquarters

HQDA Headquarters, Department of the Army

HSLLADS High-Speed, Low-Level Airdrop System

HVCDS High-Velocity Container Delivery System

HW high water

hydraulic gradient
The slope in feet per foot of a drainage structure.

hydrologic cycle
The continuous process in which water is transported from the oceans to the atmosphere to the land and back to the sea.

Hz hertz

I initial

IAW in accordance with

An irregular sheet or field of ice.

IFR instrument flight rules

ILAS Instrument Landing Approach System

IL Illinois

IMC instrument meteorological conditions

in inch(es)

The absorption of rainwater by the ground on which it falls.

in/hr inches per hour

INS Inertial Navigation System

in situ Soil in its natural (undisturbed) state.

The holding of rainfall in the leaf canopy of trees and plants.

IR infrared

Jan January

JCS PUB or Joint Pub Joint Chiefs of Staff publication

Jul July

Jun June

kg kilogram(s)

kip kilopound (1,000 pounds)

km kilometer(s)

kph kilometers per hour

kv kilovolt(s)

KVA kilo-volt-amp(s)

kw kilowatt(s)

L length

laminar flow
The type of flow that occurs when viscosity forces predominate and the particles of the fluid move in smooth, parallel paths.

landing field
A very general term designating an area of land prepared for the takeoff and landing of aircraft.

landing mat
A prefabricated, portable mat so designed that any number of planks (sections) may be rapidly fastened together to form surfacing for emergency runways, landing beaches, and so forth.

LAPES Low-Altitude Parachute Extraction System

lat latitude

lateral safety zone
An area (transitional surface) located between the runway clear area or runway edge when no clear area is provided and the clearance lines limiting the placement of building construction and other obstacles with respect to the runway centerline. The slope of the transitional surface is 7:1 outward and upward at right angles to the runway centerline.

lb pound(s)

ldg loading

lin ft linear foot/feet

LIP length in place

liq liquid

LL liquid limit

LM light mat

LOC lines of communication

LP low point

LZ landing zone

m meter(s)

M silt

MAC Military Airlift Command

MACOM major Army command

maint maintenance

MAJCOM major command

Mar March

mass diagram
Earthwork volume plotted on graph paper, showing cut and fill operations.

mat'l material

max maximum

maximum towing force (T1)
The maximum continuous towing force in pounds a vehicle can exert. It is expressed as a ratio or percentage of vehicle weight.

MCPB Mapping and Charting Program Branch

MD Maryland

mental hazard
An object, real or imaginary, not within the specified glide angles and clearance lines, but in the vicinity of the airfield, which constitutes in the mind of the pilot a hazard to the safe operation of aircraft in landing or taking off.

met meteorological

inorganic silts, micaceous or diatomaceous fine sandy or wilty soils, elastic silts

mi mile(s)

mil military

MIL-STD military standard

min minimum

min minute

inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticity

mm millimeter(s)

MM medium mat

mo month

MO maximum offset

MO Missouri

mobility index (MI)
A number that results from a consideration of certain vehicle characteristics.

MOPP mission-oriented protective posture

MOS military occupational specialty

mph mile(s) per hour

MS medium setting

MSR main supply route

MTOE modified table of organization and equipment

Slipperiness symbol meaning not slippery under any conditions.

N north

NA or N/A not applicable

NATO North Atlantic Treaty Organization

NAVAID navigational aid

NBC nuclear, biological, chemical

NCO noncommissioned officer

NCOIC noncommissioned officer in charge

NE northeast

NEACP National Emergency Airborne Command Post

NFS nonfrost-susceptible

NGR National Guard regulation

NM nautical mile(s)

NNE north northeast

NNW north northwest

no. number

NOAA National Oceanic and Atmospheric Administration

Nov November

NP number of pipes

NRMM NATO Reference Mobility Model

NRS naval radio station

NS north-south

NSN national stock number

NVG night-vision goggles

NW northwest

O offset

Oct October

OD outside diameter

OH observation helicopter

OL order length

ONC operational navigation chart

opns operations

A graded and compacted portion of the clear zone, located at the extension of each end of the runway, to minimize risk of accident to aircraft due to overrun on takeoff or undershooting on landing. Its length is normally equal to that of the clear zone and its width is equal to that of the runway and shoulders.

Slipperiness symbol meaning slippery when wet.

PAPI precision approach path indicator

para paragraph

PBS prefabricated bituminous surfacing

PC Portland cement

PC point of curvature

pcf pounds per cubic foot

pci pounds per cubic inch

PCN pavement classification number

PECS prepackaged expendable contingency supply

perm permanent

Constantly frozen ground.

PFS partially frost-susceptible

PI plasticity index

PI point of intersection

pkg parking

PL plastic limit

PO post office

POI point of impact

POL petroleum, oils, and lubricants

The accumulation of water at the upstream end of a culvert.

pop population

Pr probability

PRF penetration resistance factor

Prime BEEF prime base engineer emergency forces

psf pounds per square foot

psi pounds per square inch

PSP pierced steel plank

PT point of tangency

PVC point of vertical curvature

PVC polyvinyl chloride

PVI point of vertical intersection

PVT point of vertical tangency

QSTAG Quadripartite Standardization Agreement

qtrs quarters

RACON radar beacon

rating cone index (RCI)
The measured cone index multiplied by the remolding index (RCI = CI x RI). The RCI expresses the soil-strength rating of a soil area subjected to sustained traffic.

RAM raised angle marker

RC rapid curing

RCL recognition control light

REDCOM Readiness Command

rapid engineering deployable heavy operational repair squadrons, engineering

reg regulation

remoldable sand
A poorly drained, coarse-grained soil, usually containing 7 percent or more material passing a No. 200 sieve. Poor internal drainage increases the water content greatly influencing the trafficability characteristics and permitting the remolding test to be performed. When wet, these soils react to traffic in a manner similar to fine grained soils and are more sensitive to remolding.

The changing or working of a soil by traffic or a remolding test. The beneficial, neutral, or detrimental effects of remolding may change soil strength.

remolding index (RI)
The ratio of remolded soil strength to original strength. Soil conditions that permit the remolding test to be performed with ease will usually result in a loss of strength.

req'd or reqd required

required towing force (T2)
The force in pounds required to tow an operable, powered vehicle on level terrain.

Usually a mound or wall of earth, masonry, timber, sandbags, or other suitable material erected as a protection for aircraft against small arms or artillery fire, bomb splinters, or blast.

RI remolding index

Rocks or rubble placed in the bottom and on the sides of a ditch to prevent soil erosions.

river icing
An icing formed along rivers or streams and adjacent areas having a source of water above or below the riverbed.

RL real length

road, access
A two-way road, normally improved, connecting the air base or airfield with the existing road system of the vicinity.

The entire width of surface on which a vehicle may stand or move. The roadbed consists of both the traveled way and the shoulders.

road classification system
An organized list of four road types based on the number of vehicles each is designed to accommodate in a 24-hour period. Road characteristics are based on average daily traffic.

road, service
A road connecting the access road and the bomb and fuel storage areas with all hardstands and aprons for the purpose of refueling, rearming, and servicing aircraft.

The entire width within the limits of earthwork construction and is measured between the outside edges of cut or fill slopes. Roadway width does not include interceptor ditches if they fall outside the slopes. The roadway width varies from section to section depending on the height of cut or fill, depth of ditches, and slope ratios.

A strip of landing mat equal to one panel length and extending longitudinally (parallel to the direction of traffic) for the entire length of the runway or taxiway.

R/R recoilless rifle

RR railroad

RRR rapid runway repair

RS rapid setting

RT road tar

RT right

RTCB road-tar cutback

RTO radiotelephone operator

A strip of mat equal to one panel width and extending transversely (perpendicular to the direction if traffic) across the entire width of the runway, taxiway, or roadway.

A defined rectangular area of an airfield, prepared for the landing and takeoff run of aircraft along its length.

RW real width

R/W runway

S south

Slipperiness symbol meaning slippery at all times.

S sand

S2 Intelligence Officer (US Army)

S3 Operations and Training Officer (US Army)

SAAF small austere airfield

sand grid
A honeycomb shaped geotextile measuring 20 feet by 8 feet by 8 inches deep when fully expanded. It is used to develop a beachhead for logistics-over-the-shore operations. It is also useful in expedient revetment construction.

SC clayey sands, sand-clay mixture

SC supply catalog

SC slow curing

SCIP scarify and compact in place

SE southeast

SEATO Southeast Asia Treaty Organization

sec second

Sept September

SF standard form

SFC sergeant first class

(1) That part of the top surface of an approach embankment, causeway, or cut immediately adjoining the roadway that accommodates stopped vehicles in emergencies and laterally supports base and surface courses. (2) A graded and compacted area on either side of the runway to minimize the risk of accident to aircraft running off or landing off the runway.

shoulder slopes
These may be the same as the traveled way, but usually they are greater because shoulders are more pervious than the surface course.

sight distance restriction factor
The percent of the total length of the road on which the sight distance is less than 1,500 feet.

SKE station keeping equipment

The low traction capacity of a thin soil surface owing to its lubrication by water or mud without the occurrence of significant vehicle sinkage.

The inclined surface of an excavated cut or an embankment.

slope ratio
The relative steepness of the slope expressed as a ratio of horizontal distance to vertical distance. Thus, a 2:1 slope ratio signifies that for every 2 feet horizontally there is a rise or fall of 1 foot. The value of the slope ratio used in construction depends on the properties of the soil and the vertical height of the slope. Ditch slopes may also be governed by the amount of water to be drained and the possibility of erosion.

silty sands and poorly graded sand-silt mixture

SOCOM special operations command

SOF special operations forces

SOLL special operations low-level

SOP standing operating procedure

poorly graded sands or gravelly sands, little or no fines

spring icing
An icing whose source of water is from subpermanent levels.

sq square

sqdn squadron

sq ft square foot/feet

sq in square inch(es)

sq yd square yard(s)

Sr senior

SS slow setting

SSE south southeast

SSG staff sergeant

SSW south southwest

sta station

STANAG Standardization Agreement

The ability of a soil to adhere to the vehicle undercarriage or running gear.

stilling basin
A structure used to protect the culvert outlet against erosion.

STOL short takeoff and landing

subbase or subgrade
Describes the in situ soil on which a road, airfield, or heliport is built. The subgrade includes soil to the depth that may affect the structural design of the project or the depth at which climate affects the soil.

subsurface water
Water beneath the surface of the land.

sum summation

The transverse downward slope from the outside to the inside of the traveled way on a curve. It is usually expressed in inches of drop per horizontal foot or foot-drop per horizontal foot.

surface course
The surface course provides a smooth, hard surface on which the traffic moves. It may be constructed from asphalt or tar products, concrete, gravel, or compacted earth with certain types of binders. The surface course should be all-weather and should provide for the rapid urnoff of water. The use of treated surfaces is limited to roads that have a long design life. A divisional road with a life expectancy of 6 months or less will receive only an earth or gravel surface.

surveil surveillance

SUSV small-unit support vehicle

well-graded sands, gravelly sands, little or no fines

SW southwest

T thickness

T temporary

T1 maximum towing force

T2 required towing force

TA Theater Army

TACAN tactical air navigation

takeoff ground run (TGR)
The distance traveled by an aircraft along the runway before becoming airborne.

taxiway (txy)
A specially prepared or designated path on an airfield for the use of taxiway aircraft.

TBM temporary bench mark

TC training circular

TDF total depth of fill

temp temperature

TH thickness x height

thd thread

time of concentration (TOC)
The time it takes for an entire drainage basin to begin contributing runoff to a drainage structure.

TM technical manual

TN air transport

TNT trinitrotoluene

TO theater of operations

TOE table(s) of organization and equipment

touchdown area
That portion of the beginning of the runway normally used by aircraft for primary contact of wheels on landing.

TP transition point

traction capacity
The ability of soil to resist the vehicle tread thrust required for steering and propulsion.

traffic lane
The traffic lane consists of the road surface over which a single lane of traffic will pass.

trans transportation

The process by which water that has traveled from the ground through the plant's system is returned to the air through the leaf system.

traveled way
The road surface upon which all vehicles move or travel. For a single-lane road, the traveled way is the same as one traffic lane. For a multilane road, the traveled way is the sum of the traffic lanes. If a surface course is provided, it normally extends only across the traveled way.

trk truck

turbulent flow
The type of flow that occurs when viscosity forces are relatively weak and the individual water particles move in random patterns within the aggregate forward-flow pattern.

TYP typical

U unsurfaced soil with or without mat

UAV unmanned aerial vehicle

UH utility helicopter

UHF ultrahigh frequency

UHFDF ultrahigh frequency direction finder

US United States

USAASO United States Army Aeronautical Services Office

USAE United States Army Engineer

USAES United States Army Engineer School

USAF United States Air Force

USCS Unified Soil Classification System

util utility

UXO unexploded ordnance

V volt

VA Virginia

VASI visual approach slope indicator

VC vitrified clay

vehicle cone index (VCI)
The index assigned to a given vehicle that indicates the minimum soil strength in terms of rating cone index (or cone index for coarse-grained soil) required for one pass (VCI1 ) or other passes (VCIn )of the vehicle. Usually one and fifty passes are used as extremes.

VFR visual flight rules

VGSI Visual Glide Scope Indicating System

vis visibility

VMC visual meteorological conditions

vol volume

VTOL vertical takeoff/landing

W west

W width

W1 weight of towing vehicle

W2 weight of a towed vehicle

w/ with

w/o without

WES Waterways Experiment Station

WF waste factor

wg wing

wind sock
A long fabric cone open at both ends, used to indicate the wind direction to an airborne pilot.

wind tee
A T-shaped device for indicating landing direction to pilots.

WNW west northwest

wp wetted perimeter

W.R.C. wire rope cable

WSW west southwest

wt weight

WT weight type

yd yard(s)

yr year

ZM zone marker

< less than

< less than or equal to

> greater than

> greater than or equal to

o degrees

G change of grade

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