MAIN TERMS AND DESCRIPTIONS USED IN CIVIL AVIATION STATISTICS

Aircraft departures.   The number of take-offs of aircraft.   For statistical uses, departures are equal to the number of landings made or flight stages flown.

Aircraft daily utilization. Aircraft hours flown (block-to-block) divided by aircraft days available.

Aircraft days available. The sum of the number of days an aircraft is available for use during the period in question. The following days are excluded from the days available:

            — the days between the date of purchase of an aircraft and the date it is actually placed in service;

            — the days subsequent to an aircraft’s last revenue flight and prior to its disposal;

            — the days that an aircraft is out of service due to major accidents or conversion;

            — the days that an aircraft is in the possession of others;

            — the days that an aircraft is not available because of government action such as grounding by government regulatory agencies.

All other days must be considered as days available, even days required for maintenance or overhaul.

Aircraft hours.   Aircraft hours based on “block-to-block” time (i.e. from the moment the aircraft is pushed back from the gate or starts taxiing from its parking stand for take-off to the moment it comes to a final stop at a gate or parking stand after landing); also known as block time.

Aircraft kilometres performed. The sum of the products obtained by multiplying the number of revenue flight stages flown by the corresponding stage distance.

Aircraft movement (airports).   An aircraft take-off or landing at an airport. For airport traffic purposes one arrival and one departure is counted as two movements.

            International. All flights of national or foreign aircraft whose origin or destination is located in the territory of a State other than that in which the airport being reported on is located.

            Domestic. All flights of national or foreign aircraft in which all the airports are located in the territory of the same State.

In both cases the flight shall be considered as consisting of the total of its flight stages (i.e. from take-off to its next landing); technical stops are not taken into account.

AIS (aeronautical information services). Personnel and facilities employed to provide information pertaining to the availability of air navigation services and their associated procedures necessary for the safety, regularity and efficiency of air navigation (i.e. AIP, AIC, NOTAM, etc.).

ATM (air traffic management). Personnel and facilities employed to provide air traffic services (ATS), air traffic flow management and airspace management. ATS comprises air traffic control service (area control service, approach control service, or aerodrome control service), flight information service (including air traffic advisory service) and alerting service.

City-pair. Two cities between which travel is authorized by a passenger ticket or part of a ticket (a flight coupon) or between which shipments are made in accordance with a shipment document or a part of it (freight bill or mail delivery bill).

CNS (communications, navigation and surveillance). CNS includes communication facilities, navigation services and surveillance systems. Communication facilities may be broadly classified under two main categories: aeronautical fixed service and aeronautical mobile service.

            Aeronautical fixed service (AFS). All facilities and personnel employed to provide telecommunication services between fixed points, such as AFTN/ATS, the ground part of ATN and ATS direct speech and data circuits.

            Aeronautical mobile service (AMS). All ground-based facilities and personnel engaged in air-ground communications and radiotelephony broadcasts such as ATIS and VOLMET (i.e. VHF and HF transmitting and receiving stations). Implementation of AMSS, as well as other ATS air-ground links and other communications subnetworks of the future ATN, will add satellites or satellite transponders and associated ground earth stations.

Navigation services comprise ground-based radio navigation equipment (e.g. VOR, DME and NDB) and precision approach and landing aids (e.g. ILS equipment). Implementation of GNSS will add the satellite constellations providing the standard signal positioning service and the associated augmentation systems required, i.e. satellite-based (wide-area) and ground-based (local area) augmentations. Surveillance systems comprise primary surveillance radar (PSR), secondary surveillance radar (SSR), including SSR Mode S, surface movement radar (SMR) as well as automatic dependent surveillance (ADS), including the supporting network and maintenance personnel.

Commercial air transport operator . An operator that, for remuneration, provides scheduled or non-scheduled air transport services to the public for the carriage of passengers, freight or mail. This category also includes small-scale operators, such as air taxi operators, that provide commercial air transport services.

Direct transit passengers. Passengers who continue their journey on a flight having the same flight number as the flight on which they arrived. Passengers in direct transit are counted only once. Other transit passengers and stop-over passengers are counted twice: once as embarked passengers and once as disembarked passengers.

Distance flown per passenger. The average distance flown per passenger is computed by dividing the passenger-kilometres by the related number of passengers carried.

Domestic flight.   A flight having exclusively domestic stages. (See flight stage, domestic).

FIR/UIR. Flight information region/upper flight information region.

Flight (air carrier operations). The operation of an aircraft on a flight stage or number of flight stages with the same flight number.

Flight (air navigation). The movement of an aircraft during its en-route phase through the airspace of an FIR/UIR. Each such movement following a landing within the FIR/UIR is to be counted as a separate flight.

Flight coupon. Each component part of a ticket containing separate travel authority for subdivisions of the total travel covered by the passenger ticket.

Flight stage. A flight stage is the operation of an aircraft from take-off to its next landing. A flight stage is classified as either international or domestic based on the following definitions:

            International . A flight stage with one or both terminals in the territory of a State, other than the State in which the air carrier has its principal place of business.

            Domestic . A flight stage not classifiable as international. Domestic flight stages include all flight stages flown between points within the domestic boundaries of a State by an air carrier whose principal place of business is in that State. Flight stages between a State and territories belonging to it, as well as any flight stages between two such territories, should be classified as domestic. This applies even though a stage may cross international waters or over the territory of another State.

           Notes:

            1.   In the case of multinational air carriers owned by partner States, traffic within each partner State is shown separately as domestic and all other traffic as international.

2.   “Foreign” cabotage traffic (i.e. traffic carried between city-pairs in a State other than the one where the reporting carrier has its principal place of business) is shown as international traffic.

3.   A technical stop does not result in any flight stage being classified differently than would have been the case had the technical stop not been made.

Freight (or mail) loaded/unloaded (airport). These terms as applied to freight and mail have meanings similar to embarked and disembarked for passengers.

Freight (or mail) tonnes carried.   The number of tonnes of freight carried is obtained by counting each tonne of freight on a particular flight (with one flight number) once only and not repeatedly on each individual stage of that flight.   The only exception to this is for freight flown on both the international and domestic stages of the same flight, which is considered in computation both as a domestic and an international shipment or dispatch.   The same principle should be used in calculating mail tonnes carried.

Freight (or mail) tonne-kilometres performed.   A metric tonne of freight or mail carried one kilometre.   Freight tonne-kilometres equal the sum of the products obtained by multiplying the number of tonnes of freight, express, diplomatic bags carried on each flight stage by the stage distance. For ICAO statistical purposes freight includes express and diplomatic bags but not passenger baggage.   Mail tonne-kilometres are computed in the same way as freight tonne-kilometres.

General aviation (GA) activities. All civil aviation operations other than scheduled air services and non-scheduled air transport operations for remuneration or hire (Annex 6 Part II).   For ICAO statistical purposes the general aviation activities are classified into instructional flying, business and pleasure flying, aerial work, and other flying.

International airport.   Any airport designated by an ICAO Contracting State in whose territory it is situated as an airport of entry and departure for international air traffic, where the formalities incident to customs, immigration, public health, agricultural quarantine and similar procedures are carried out.

International flight. A flight that contains one or more international flight stages. (See flight stage,   international).

Mail.   All correspondence and other objects tendered by and intended for delivery to postal administrations.

MCTOM .   Maximum certificated take-off mass (MCTOM) (in metric tonnes) according to the certificate of airworthiness, the flight manual or other official documents.

Non-scheduled revenue flights. Charter flights and special flights performed for remuneration other than scheduled flights.

Number of seats.   The number of passenger seats installed in an aircraft. Where aircraft of the same type have different numbers of passenger seats installed, e.g. 80-seater, 90-seater and 100-seater, a range may be shown thus: 80 - 100.

Operating expenses per traffic-unit (unit cost).   This is a type of financial measurement which relates the traffic or capacity applicable to the operating expenses.   It is computed by dividing the operating expenses by the tonne-kilometres performed or by the tonne-kilometres available.

Operating revenue per traffic-unit (operating yield).   This is a type of financial measurement which relates the traffic or capacity applicable to the operating revenues.   It is computed by dividing the operating revenues by the tonne-kilometres performed or by the tonne-kilometres available.

Passengers carried.   The number of passengers carried is obtained by counting each passenger on a particular flight (with one flight number) once only and not repeatedly on each individual stage of that flight, with a single exception that a passenger flying on both the international and domestic stages of the same flight should be counted as both a domestic and an international passenger.

Passengers, embarked/disembarked (airport)

Embarked passengers. Number of revenue and non-revenue passengers whose air journey begins at the reporting airport, including the number of disembarked passengers, other than direct transit passengers, who are continuing their air journey.

Disembarked passengers. Number of passengers whose air journey terminates at the reporting airport, including the number of passengers, other than direct transit passengers, who will continue their air journey.

Passenger, freight and mail (airport)

            International. Applies to passengers, freight and mail disembarked at an airport located in a State other than that of the airport of embarkation, or vice versa.

            Domestic. Applies to passengers, freight and mail disembarked at an airport located in the State of the airport of embarkation or vice versa.

Passenger-kilometres performed.   A passenger-kilometre is performed when a passenger is carried one kilometre.   Calculation of passenger-kilometres equals the sum of the products obtained by multiplying the number of revenue passengers carried on each flight stage by the stage distance.   The resultant figure is equal to the number of kilometres travelled by all passengers.

Passenger load factor.   Passenger-kilometres performed expressed as a percentage of seat-kilometres available.

Passenger revenue per traffic-unit (passenger yield).   This is a type of financial measurement which relates the passenger traffic applicable to the passenger revenues.   It is computed by dividing passenger revenues by the passenger-kilometres performed.

Passenger tonne-kilometres performed.   Passenger tonne-kilometres performed are obtained by applying a standard weight per passenger to the passenger-kilometres performed.   (See also passenger weight.)

Passenger weight. To convert aircraft passenger loads into weight loads, the number of passengers carried is multiplied by a factor representing the average weight of the passenger plus both normal baggage allowance and excess baggage. This conversion factor is left to the discretion of the operator. However, if no conversion factor is available, it is recommended that 90 kilograms be used. (See also passenger-tonne-kilometres performed.)

Payload capacity. Total payload capacity available (in metric tonnes), above and below deck, for the carriage of revenue load (passengers, baggage, freight and mail) taking into account payload restrictions, where applicable, and operational restrictions on the supply of capacity. (See also tonne-kilometres available.)

Personnel, annual expenditures. Covers the gross salary (before deduction of income tax, pension, social welfare and voluntary payments), overtime pay, flying pay, and subsistence allowances, such as cost-of-living, station and overseas allowances. Does not include expenses for travelling, moving, training, uniforms, etc.

Register of aircraft.   An official State register listing all civil aircraft owned by operators for civil aviation purposes.

Revenue passenger. A passenger for whose transportation an air carrier receives commercial remuneration.   (See also passengers carried..)

Notes:

            1.   This definition includes, for example, a) passengers travelling under publicly available promotional offers (for example, “two-for-one”) or loyalty programmes (for example, redemption of frequent-flyer points); b) passengers travelling as compensation for denied boarding; c) passengers travelling on corporate discounts; d) passengers travelling on preferential fares (government, seamen, military, youth, student, etc.).

2.   This definition excludes, for example, a) persons travelling free; b) persons travelling at a fare or discount available only to employees of air carriers or their agents or only for travel on business for the carriers; c) infants who do not occupy a seat.

Seat-kilometres available. A seat-kilometre is available when a seat is flown one kilometre.   Seat-kilometres available are equal to the sum of the products obtained by multiplying the number of passenger seats available for sale on each flight stage by the stage distance.   It excludes seats not available for the carriage of passengers because of the weight of fuel or other loads (see also payload capacity).

Scheduled revenue flights. Flights scheduled and performed for remuneration according to a published timetable, or so regular or frequent as to constitute a recognizably systematic series, which are open to direct booking by members of the public; and extra section flights occasioned by overflow traffic from scheduled flights.

Speed flown.   The average aircraft speed flown is obtained by dividing the aircraft kilometres flown by the related aircraft hours. Where the latter are block-hours flown, the result is known as the average block speed.

Stage distance flown per aircraft.   The average stage distance flown per aircraft is obtained by dividing the aircraft kilometres flown by the related number of aircraft departures.

Tonne-kilometres available.   A tonne-kilometre is available when one tonne of payload capacity is flown one kilometre.   Tonne-kilometres available equals the sum of the products obtained by multiplying the number of tonnes available for the carriage of revenue load (passengers, freight and mail) on each flight stage by the stage distance. (See also payload capacity.)

Tonne-kilometres performed.   A metric tonne of revenue load carried one kilometre.   Tonne-kilometres performed equals the sum of the product obtained by multiplying the number of total tonnes of revenue load (passengers, freight and mail) carried on each flight stage by the stage distance.

Traffic.   For air transport purposes, traffic means the carriage of passengers, freight and mail.

Weight load factor.   Tonne-kilometres performed expressed as a percentage of tonne-kilometres available.

For a more comprehensive list of terms used in this web site, please refer to the Reporting Instructions attached to the ICAO Air Transport Reporting Forms associated with each data series shown in http://www.icao.int/icao/en/atb/sea/forms.htm.