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overload the air traffi c control (ATC) system
somewhere along the route. Regional Flow
Management Units emerged, but each State
tended to protect its own airspace from
overload at the expense of its neighbour.
Some system of centralised phasing
of demand in time and space was clearly
needed and an air traffi c fl ow management
planning group had been established at the
International Civil Aviation Organization’s
request by EUROCONTROL in 1980, during
Jean Lévêque’s term as director general.
One of its aims was to establish a central
data bank (CDB) of air traffi c demand. Work
started on the CDB at Brussels in December
1981 and the system was completed in
June 1984.
Lévêque described the West European
air traffi c picture at the time as “a complex
mix of diff erent types of aircraft and of fl ight
operations, a high proportion of aircraft in
climb and descent… the intersection of the
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dionsed tiscil
Many airports were reaching
saturation point, struggling to process
aircraft through limited taxiways,
runways and parking areas
major northwest/southeast, north-south and
north-southeast fl ows, often over areas of
intense civil terminal and military traffi c…
a major problem of international and civilmilitary
coordination”.
Aircraft cannot stop in the sky, they can
only keep position by circling – known
as ‘holding’ – which uses extra fuel, takes
up levels of valuable airspace, and blocks
other aircraft movements. Aircraft can
never reduce speed suffi ciently to make
any particular diff erence to traffi c management.
Re-routeing by ATC is an option, but
this can cause cost increases in terms of fuel
consumed and rostering of substitute crews
as fl ight hours build up. Takeoff s may be
rescheduled, but all options generate delays
unless a balance between demand and capacity
is found in advance by some concept
of fl ow management.
A survey by the International Air Transport
Association, of journeys in the summer
of 1981, showed that 25 per cent of fl ights
through south and southeastern Europe were
delayed by air traffi c services for an average
of 33 minutes. Not all these delays could be
attributed to fl ow control – many airports
were reaching saturation point, struggling
to process aircraft through limited taxiways,
runways and parking areas. Industrial unrest,
too, sometimes played its part, but fl ow control
was the biggest issue and the problem
became worse during the decade.
Traffi c peaks occurred both in the holiday
seasons and all year round during certain
times of day. Over a four-year period in the
second-half of the decade, the number
of fl ights delayed by at least 15 minutes
almost doubled. Notably, 1987 and 1988
were marked by worsening delays for both
holiday and scheduled travellers and ATM
was now the subject of serious political and
media attention in Europe.
An opportunity was emerging for
EUROCONTROL to take an active role in
ATM. EUROCONTROL’s role as navigation
charge price clearing house had continued
unchanged during the 1980s, but the revised
Convention of 1981, ratifi ed in January
1986, removed the objective of achieving
common upper airspace ATC in Europe and
placed the emphasis on study, research and
harmonisation activities. The internal structure
of EUROCONTROL did not change and it
was still possible for the organisation to take
direct operational responsibility for air traffi c
at the request of one or more States.
Creating the Central Flow
Management Unit
EUROCONTROL’s CDB computer, located
alongside the operations and engineering
directorates at its Brussels headquarters,
had come online in 1984, initially taking in
data from airline timetables. The CDB computer,
which by 1985 held data on 18,000
routes and 40,000 city pairs, had the potential
to contribute to the establishment of a
Central Flow Management Unit (CFMU), if
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Reaching for the Single European Sky(65)
