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future. European
air traffic management
has taken up the
challenge.
Joe Sultana, Deputy
Director Central Flow
Management Unit,
explains how.
Capacity, flight efficiency
and emissions
– the eternal triangle
CAPACITY
FLIGHT
EFFICIENCY Airspace
Network
Performance
5
eternal
triangle
Background
From the start, the primary task of air
traffic control (ATC) has been safety, i.e.
preventing collisions between aircraft
in the air and on the ground. Eventually
the phrase ‘expeditious flow of air traffic’
became part of the bible for all controllers
(ICAO PANS DOC 4444).
In truth ATC training never really focused
on what “expeditious” meant and
controllers were left to devise their own
tactical procedures, such as to clear
aircraft direct to the furthest possible
point in their sector or FIR.
As traffic levels grew and the first
delays started to hit European ATM
in the late 70s and early 80s, holding
patterns were designed and aircraft
holding inside the major TMAs became
a common occurrence. Eventually flow
control was introduced both for
safety and to absorb delays at the
departure airport.
With the traffic build-up in the 1990s
and the increase in delays, flow control
had to be combined with capacityincreasing
measures. Capacity
became the buzzword and all efforts
of national and Agency experts were
dedicated to increasing capacity and
reducing delay. Some concepts such
as Reduced Vertical Separation Minima
(RVSM) had the benefit of increasing
capacity and improving flight efficiency.
Airspace redesign, making use of
area navigation capabilities and flight
level capping, had a significant positive
impact on European capacity and
delay reduction. Having the freedom
to put routes anywhere has resulted in
the design of routes which spread out
the traffic for capacity reasons, with a
somewhat negative effect on flight efficiency,
increasing the overall route length
and preventing aircraft from flying their
preferred vertical flight profiles.
With the price of fuel below $40, the
capacity side of the triangle dominated
ATM operational improvement efforts.
The network was optimised for increased
capacity, delays went down to below the
Provisional Council’s target, whilst ATC
was mitigating for flight inefficiencies at a
tactical level.
Aircraft operators reverted to looking
at how to make profit for a change and
started to ask for capacity without flight
inefficiencies, i.e. they resisted the introduction
of routes which were longer than
the ones they replaced and complained
about the capping of flights at uneconomical
flight levels. Environmental
concerns became something more than
airport noise issues. EUROCONTROL
activities to measure flight inefficiencies,
emission mitigation projects such
as Continuous Descent Approach
(CDA) projects and a more collaborative
approach with aircraft operators on flow
measures, which substituted delays for
longer routes, were a first response to
meeting the airlines’ requests.
Skyway 50 - Winter 2008
EMISSIONS
With the price of fuel
below $40, the capacity
side of the triangle
dominated ATM
operational
improvement efforts.
6
Focus
Capacity, flight efficiency and emissions – the eternal triangle
In reality, however, delays were still the
principal performance indicator. The political
and top management will to make
it happen was not there. The triangle
was heavily tilted towards the capacity
vertex. The airlines’ operating cost equation
was still dominated by the cost of
delay. It took the growing green agenda
in Europe in the early part of this decade
to move emissions more into the political
frame, with the European Commission
becoming more vocal on emissions and
ATM starting to take the issue more seriously.
Airline associations recognised
this change, reviewed their own operating
procedures and asked ATM to do
likewise. It was politically correct (fuelefficient)
to introduce CDAs on a trial basis,
but still not at the expense of capacity.
Flight Efficiency Plan
Then, the price of fuel shot up, first closer
and closer to $80-90, then past $100
and then way beyond to nearly $150.
Airlines faced what they called the perfect
storm – unaffordable operating costs and
plunging markets. Suddenly carrying
　
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本文鏈接地址：Skyway Magazine Spring 2009(3)