Memorandum by Airport Coordination Limited
The IATA Scheduling Procedures Guide provides
the framework for slot allocation for all Coordinators world-wide
and sets the timetable of events in the scheduling process.
The coordination process at all UK airports
is consistent with the IATA guidelines.
The guidelines are, of necessity, broadly framed
to allow the unique problems at each airport to be resolved locally
by the Coordinator in a flexible manner acceptable to the airlines,
the Airport Operator and the Authorities, e.g., HM Customs.
The process used by each Coordinator to resolve
the scheduling problems at their airports varies widely. The approach
may even vary from season to season.
The process is driven by the dynamics of changing
capacity/demand, IATA guidelines. Regulations (National or EU),
local rules and the availability of technology, time, resources,
It is therefore impossible to be prescriptive
about the process and criteria but the details below give a broad
A "slot" is the scheduled time of
arrival or departure available or allocated to an aircraft movement
on a specified date at an airport.
1. Day to day schedule changes by airlines throughout
each season are evaluated by the Coordinator and processed as
either an ad hoc, a temporary change to an historic schedule,
or a permanent change to the historic schedule.
2. In September each year, what the Coordinator
considers to be the Summer historic schedule is sent to each airline
for checking. This ensures any disagreements between the airline
and the Coordinator can be resolved before the schedule submissions
for the next Summer season in October. (Winter historics are established
in April before schedule submissions in May).
The historic schedule is based upon the results
of the slot monitoring process undertaken by the coordinator throughout
that season. Clarity about the historic baseline is then established
before the submissions are received from the airlines by the Coordinator.
3. The scheduling limits (runway, terminals,
stands etc.) are normally negotiated with the Airport Operator
control authorities and the airlines around the same time that
the historic schedule is sent out.
Agreement is normally reached on the scheduling
limits, and the constraints associated with them, to be applied
by the Coordinator shortly before the submission deadline.
1. Airline schedule requests are submitted to
the Coordinators by midnight on the schedule submissions deadline
set by IATA. This is normally in May for Winter season and in
October for a Summer season. This produces a picture of "Raw
Demand" (unconstrained demand) for the airport and for the
2. Prior to any slot allocation decisions the
schedule data which has been submitted by the airlines is generally
sorted into one of four categories:
(i) Historic Slotsthere is some flexibility
here as some changes are allowed which do not materially effect
coordination parameters e.g., flight number change. More significantly
changes which may have capacity implications, e.g., substitution
of a larger aircraft, timing adjustment etc. are put into the
second group called Changed Historics.
(ii) Changed Historicsthese are flights
for which the airline already holds an historic slot but which,
for a variety of operational or commercial reasons, have been
requested at a different timing, or with a larger aircraft etc.
(iii) New Entrantsthe new entrant
group of schedules is further subdivided between new airlines
to the airport and new services requested by incumbent airlines
but qualifying under the "no more than four slots on a day"
or "intra-community route" criteria in the IATA Guidelines
and EC Regulations.
(iv) New Incumbentsthese are all new
slot requests by existing operators not qualifying as new entrants.
3. Initially, all Historic Slots and Changed
Historic slots are put into the new seasonal database.
4. Changed Historics which breach the scheduling
limits are rescheduled as close to their required time as possible
but within the scheduling limits.
5. The net result of this process, which takes
a numbr of days, is a fully coordinated airport within all the
scheduling limits but based entirely on Historic and Changed Historic
schedules. Approximately 10 per cent of airlines historic schedules
are changed each season. Schedule adjustments by the Coordinator
to meet scheduling limits have been minimised.
1. Once Historic and Changed Historic schedules
have been accommodated any new capacity is added to the process.
New capacity may arise from higher scheduling limits, historic
slots no longer required by carriers and slots lost under use-it-or-lose-it
rules. This provides the pool of slots available for allocation
to new requests.
2. The allocation of new slots then beginsup
to 50 per cent of the new capacity is allocated to new entrants
both new to the airport and qualified new entrants with the remaining
50 per cent being allocated to new requests by incumbent carriers.
If the 50 per cent available to new entrants is not fully subscribed,
the remaining slots are also allocated to new flights by incumbent
Slots are considered by the Coordinator on a
day by day hour by hour basis. For each hour that slots are available
the Coordinator considers which airlines are requesting slots,
i.e., who is on the "waiting list".
The feasibility of each allocation decision
is tested by adding the selected flight to the Coordinator's computer
database which contains a mathematical model of airport capacity
and scheduling limits. No flights are added which break scheduling
3. The criteria used in the allocation decision
process are summarised below and are the same for new entrants
and incumbent operators.
Introduction of YearRound
Effective Period of Operation
Size and Type of Market served
World-wide scheduling constraints
Needs of the travelling public
Other criteria which are taken into consideration
at UK Airports are:
Night Flying Restrictions
Effect of Traffic Distribution
Rules e.g., peak hours
Bilateral issues e.g. frequencies
allowed on route
Airlines which have applied for
a particular slot in previous seasons (seasonal waiting list)
"Sharing out" the limited
available capacity between the carriers
Ad-hocs; Trade fairs etc. are
given lower priority
4. A large number of slots remain available
even at the end of the coordination process though the number
is diminishing at many airports. This is because some slots are
Following the coordination process, listings
are produced for each airline showing the slots requested and
the slots offered and, where there is any variance, the reasons
for the change are shown.
These listings, and many like them, are distributed
by Coordinators to the airlines on the first day of the IATA Schedule
Coordination Conference which is held twice a year in June (for
Winter seasons) and November (for Summer seasons).
THE IATA CONFERENCE
The objective of the IATA Conference is to agree
the slot allocations for the coming season between airlines and
Coordinators for airports around the world.
The airlines attending have other objectives
such as optimising connections and ground handling arrangements.
The Conference is attended by airlines and Coordinators
and up to 650 delegates may attend.
Some airlines and Coordinators set up a sophisticated
operation (i.e., office, computer systems, staff, etc.) and some
are quite unsophisticated.
The process of the Conference is for airlines
to make brief appointments to see the Coordinators of the airports
they plan to serve in the coming season and then to meet and discuss/agree
the feasibility of the proposed schedule.
Airlines engage in slot exchanges with one another
in order to improve the slots which they hold.
The dialogue between the Coordinator and the
airlines on scheduling matters continues long after the IATA Conference
and into the operating season as the airlines add, change and
delete their flights as changes by one airline may release slots
which can benefit other airlines.
In the period after the Conference, many airlines
engage in slot exchanges in order to improve the slots which they
STRUCTURE OF THE UK SLOT ALLOCATION SYSTEM
1. A system for managing the imbalances between
airline demand and airport capacity has been developed over many
years under the auspices of IATA through a process of schedule
coordination and slot allocation.
2. In most countries, though not all, this work
is undertaken by the "national" carrier or the largest
operator at each airport, e.g., Olympic Airways takes responsibility
for slot allocation at all Greek airports.
3. In the UK British Airways (BA) held responsibility
for slot allocation at Heathrow, Gatwick, Manchester and Birmingham
at the request of the airlines serving these airports.
Within BA a "chinese wall" existed
between the coordination team responsible for slot allocation
and the rest of BA to ensure the necessary neutrality.
4. The criteria used for decisions on slot allocation
are those laid down by IATA combined with a complex set of UK
and European Regulations.
5. For many years the Airport Operators at each
coordinated airport (e.g., HAL at Heathrow) made a financial contribution
to BA towards the cost of providing the coordination service and
a contractual relationship existed between the Airport Operators
6. In the late 1980's the European Commission
(EC) became interested in the slot allocation system for two primary
(i) The Commission was concerned about bias
in slot allocation decisions in some countries.
(ii) The slot allocation system was perceived
as a significant obstacle to the liberalisation of air transport,
particularly after the introduction of the Single European Market.
7. In 1991 BA decided to change its relationship
with the coordination team in BA and formed a separate subsidiary
company, Airport Coordination Limited (ACL), to take over BA's
responsibilities for slot allocation.
The primary objectives were:
To increase the perceived neutrality
of the coordination process.
To reduce the need for regulatory
intervention by the EC.
To broaden the participation in the
UK slot allocation system.
Airport Coordination Limited
1. Throughout 1991 BA negotiated with eight
other airlines about the structure and ownership of ACL.
The Airport Operators, the CAA, the Department
of the Environment, Transport and the Regions and the European
Commission were also consulted.
2. Airport Coordination Limited was re-established
as an independent company Limited by Guarantee and jointly owned
by nine UK airlines on 27 May 1992.
Since 1992 airline membership of ACL has grown
to 11 airlines.
These 11 airlines make a financial contribution
towards ACL's running costs without any involvement in the slot
allocation decisions which are made by Coordinators appointed
3. Membership of ACL is "open to all those
Airlines who from time to time express an interest in the allocation
of slots" at UK airports.
4. ACL is an administrative organisation primarily
responsible for the delivery of data collection, schedule coordination
or, slot allocation services under contract (Coordination Agreements)
to Airport Operators and has no policy making role.
The Coordination Agreements lay down performance
ACL receives funding from the Airport Operators
which contributes towards ACL's running costs.
5. ACL now serves 12 airports, Heathrow, Gatwick,
Manchester, Birmingham, Luton, Glasgow, Edinburgh, Aberdeen, Stansted,
Newcastle, London City and Jersey.
6. A slot Regulation was finally introduced
in January 1993 as EC Regulation 95/93 on the allocation of slots
at Community airports with the objective of increasing transparency
and neutrality of the scheduling process, to avoid discrimination
between operators and to provide opportunities for new entrants.
ACL meets all these objectives.
7. The EC Regulation was followed by the introduction
of a UK Statutory Instrument 1993 No. 1067 in May 1993 which brought
the EC Regulation into UK law.
ACL has now been formally appointed by the Airport
Operators and approved by the Secretary of State for Transport
to be responsible for schedule coordination and slot allocation
at most major airports in the UK.
1. The Airline Scheduling Committees have existed
in the UK for many years.
2. Each Scheduling Committee is an un-incorporated
association and is the representative body for all the Airline
Operators having expressed an interest in the allocation of slots
and coordination of schedules at a particular airport.
Each Committee is responsible for developing,
within the IATA Guidelines, local scheduling guidelines and advising
the Coordinator. Local guidelines may be necessary for scheduling
issues not covered by the IATA Guidelines, e.g., administration
of night noise quotas.
3. As an example the Constitution of the Heathrow
Scheduling Committee shows its purpose to be:
(a) to formulate scheduling policies and
guidelines specific to Heathrow;
(b) to advise the Coordinator in connection
with the efficient allocation of slots and coordination of schedules
at Heathrow; and
(c) to represent the views of Heathrow Operators
on scheduling matters.
(d) To negotiate reductions in constraints
on capacity on behalf of all Heathrow Operators and promote improvements
in the utilisation of facilities.
(e) To solve by mediation problems involving
conflicting demands for slots.
The Scheduling Committee has no responsibility
for the allocation of slots.
4. To overcome the logistical difficulties of
large meetings, each Scheduling Committee elects a representative
Executive Committee to undertake the work of the Scheduling Committee.
5. Members of the Scheduling Committee participate
in the Coordination Committee as the airlines' representatives.
1. EC Regulation 95/93 requires the formation
of a Coordination Committee (Article 5) at fully coordinated airports
(Heathrow, Gatwick and Manchester in the UK).
2. Membership of the Coordination Committees
includes airlines, the Airport Operator, Air Traffic Control and
General/Business Aviation representatives.
3. The role of the Coordination Committee is,
inter-alia, to advise the Coordinator (ACL) on such matters
as increasing airport capacity, methods for monitoring the use
of allocated slots, local guidelines for slot allocation, etc.
4. The Coordination Committee can also deal
with any complaints on the allocation of slots or problems experienced
by new entrants in obtaining slots which are referred to it by
the airlines or the Scheduling Committee.
1. The Airport Operator (e.g., HAL at Heathrow)
has the ultimate statutory authority for the allocation of slots
at the airport under the Airports Act 1986.
2. The Airport Operator at each airport has
signed a service contract (Coordination Agreement) with ACL for
the provision of a Coordination Service.
3. The Airports agree to "ratify all acts,
deeds and things done by ACL in the course of and whilst acting
within the terms of ACL's appointment".
The terms of appointment specify that ACL will
carry out its function "in accordance with guidelines issued
by the International Air Transport Association (IATA) to best
industry standards and in accordance with all applicable laws
and regulations and properly formulated and adopted IATA and Scheduling
4. The scheduling limitations of airport facilities
are negotiated and agreed with the Airport Operators e.g., Runways,
Terminals, Stands etc., usually twice each year. ACL agrees to
use all reasonable endeavours to meet the scheduling limits set
by the Airport Operators.
5. ACL provides schedule data to the Airport
Operators electronically on a regular basis with details of airline
schedules based on allocated slots.
1. The European Commission has taken a keen
interest in the allocation of slots at Community Airports since
2. The EC introduced a Block Exemption for the
allocation of slots at Community Airports to provide an exemption
under Articles 85 and 86 of the Treaty of Rome subject to certain
conditions e.g., the neutrality and transparency of the slot allocation
The Block Exemption is due for renewal in 1998.
3. In January 1993, after extensive industry
consultation, the EC introduced EC Regulation 95/93 on the common
rules for the allocation of slots at Community airports.
4. There have been a number of reviews of the
working of the existing Regulation and the industry has been consulted
on early drafts of a replacement Regulation which the EC is intending
UK REGULATORY AUTHORITIES
1. The Civil Aviation Authority and Department
of the Environment, Transport and Regions maintain an arms length
relationship with ACL and have no direct involvement in the slot
2. However Regulations, such as the Night Noise
Restrictions, continue to influence the priorities for slot allocation
in the UK.
3. The UK Statutory Instrument 1993 No. 1067
(The Airports Slot Allocation Regulations 1993) gives effect in
UK law to the EC Regulation 95/93 on common rules for the allocation
of slots at Community airports.
4. The Civil Aviation Authority informally monitors
ACL's performance and has produced a number of reports on the
results of ACL's slot allocation decisions.
1. The voluntary IATA system for the allocation
of slots and coordination of schedules continues to provide the
world-wide framework for slot allocation.
2. IATA Conferences are held twice each year
and revisions to the principles, practices and priorities of slot
allocation are discussed by the airline industry and the guidelines
are changed when consensus is achieved.
3. The most fundamental principle of the IATA
system is that of "historic precedence". This principle
has been recognised and endorsed in EC Slot Regulation 95/93.
11 February 1998