THE NATIONAL AIRSPACE SYSTEM

DEFINITIONS

Air Carrier-- An aircraft with a seating capacity of more than 60 seats or a maximum payload capacity of more than 18,000 pounds carrying passengers or cargo for hire or compensation. This includes US and foreign flag carriers.

Air Route Traffic Control Center -- A facility established to provide air traffic control service to aircraft operating on an IFR flight plan within controlled airspace and principally during the en route phase of flight. When equipment capabilities and controller workload permit, certain advisory/assistance service may be provided to VFR aircraft.

Air Taxi -- An aircraft designed to have a maximum seating capacity of 60 seats or less or a maximum payload capacity of 18,000 pounds or less carrying passengers or cargo for hire or compensation.

Air Traffic -- Aircraft operating in the air or on airport surfaces, exclusive of loading ramps and parking areas.

Air Traffic Control Service (ATC) -- A service provided by a control tower for aircraft operating on the movement area and in the vicinity of an airport.

Aircraft Contacted -- Aircraft with which the flight service stations have established radio communications contact. One count is made for each en route landing or departing aircraft contacted by a flight service station regardless of the number of contacts made with an individual aircraft during the same flight. A flight contacting five FSSs would be counted as five aircraft contacted.

Airport Advisory Service -- A service provided by flight service stations at airports not served by a control tower. This service consists of providing information to arriving and departing aircraft concerning wind direction/speed-favored runway, altimeter setting, pertinent known traffic/field conditions, airport taxi routes/traffic patterns, and authorized instrument approach procedures.

Airport Operations -- The number of arrivals and departures (takeoffs and landings) from the airport at which the airport traffic control tower is located. There are two types of operations: local and itinerant.

1. Local operations are performed by aircraft which:

(a) operate in the local traffic pattern or within sight of the airport;

(b) are known to be departing for, or arriving from, flight in local practice areas located within a 20-mile

radius of the airport;

(c) execute simulated instrument approaches or low passes at the airport.

2. Itinerant operations are all aircraft operations other than local operations.

Airport Traffic Control Tower -- A terminal facility which, through the use of air/ground communications, visual signaling, and other devices, provides Air Traffic Control services to airborne aircraft operating in the vicinity of an airport and to aircraft operating on the movement area. These towers may be operated by the FAA or by a municipality. The municipality has the option of using its own employees or subcontracting for these services.

Approach -- The last phase of flight before landing

Defense Visual Flight Rules (DVFR)-- Rules applicable to flights within an Air Defense Identification Zone conducted under the visual flight rules in Federal Air Regulation, Part 91.

Flight Plan --Specified oral or written information about the intended flight of an aircraft that is filed with air traffic control.

Flight Plans Originated -- The first flight service station which receives a flight plan.

Flight Service Station -- Air traffic service facilities within the National Airspace System which provide preflight pilot briefings and en route communications with VFR flights, assist lost IFR/DVFR & VFR aircraft, assist aircraft having emergencies, relay ATC clearances, originate, classify, and disseminate NOTAMS, broadcast aviation weather and NAS information, receive and close flight plans, monitor radio NAVAIDS, notify search & rescue units of missing VFR aircraft and operate the national weather teletypewriter systems. In addition, at selected locations, FSSs take weather observations, issue airport advisories, administer airmen written examinations, and advise Customs & Immigration of transborder flights.

General Aviation Operations -- Takeoffs and landings of all civil aircraft, except those classified as air carriers or air taxis.

IFR Aircraft Handled -- The number of ARTCC IFR departures multiplied by two, plus the number of IFR overs. This formula assumes that the number of departures is equal to the number of arrivals.

IFR Departures -- An IFR flight which originates in an ARTCC's area and enters that center's airspace.

IFR Overs -- An IFR flight that originates outside the ARTCC areas and passes through the area without landing.

Instrument Approache -- Approach made to an airport by an aircraft with an IFR flight plan when visibility is less than 3 miles or ceiling is at or below the minimum initial approach altitude.

Instrument Flight-- Basic flight operation without reference to outside visual cues.

Instrument Flight Rules (IFR)-- Rules governing the procedures for conducting instrument flight.

Instrument Operation -- Arrivals or departures of an aircraft in accordance with an IFR flight plan or special VFR procedures or an operation where IFR separation between aircraft is provided by a terminal control facility

International Flight Service Station (IFSS)-- A central operations facility in the flight advisory system, manned and equipped to control aeronautical point-to-point telecommunications, and air/ground telecommunications with pilots operating over international territory or waters, providing flight plan following, weather information, search and rescue action, and other flight assistance operations.

Military Operations -- All classes of military operations at FAA air traffic facilities.

National Airspace System (NAS)-- The common network of US airspace; air navigation facilities, equipment and services, airports or landing areas; aeronautical charts, information and services; rules, regulations and procedures, technical information, and human resources and material.

Navigational Aids (NAVAIDS )-- Any visual or electronic device airborne or on the surface which provides point-to-point guidance information or position data to aircraft in flight.

Notices To Airmen (NOTAMS)-- A notice containing information (not known sufficiently in advance to publicize by other means) concerning the establishment, condition, or change in any component (facility, service, or procedure of, or hazard in the NAS) the timely knowledge of which is essential to personnel concerned with flight operations.

Pilot Briefing -- A service provided by a FSS, AFSS, IFSS, AIFSS to assist pilots in flight planning. Briefing items may include weather information, NOTAMS, military activities, flow control information, and other items as requested.

Telephone Information Briefing Service (TIBS)-- A continuous telephone recording of meteorological and/or aeronautical information.

Total Automated Flight Services -- The sum of TFS, plus TIBS Calls Received, plus NOTAMS.

Total Flight Services (TFS)-- The sum of flight plans originated and pilots briefs multiplied by two, plus the number of aircraft contacted.

Visual Flight Rules (VFR)-- Rules that govern the procedures to conducting flight under visual conditions.