AIRSPACE CONGESTION:
Pre-Tactical Measures
and
Operational Events
ICRAT Conference, Zilina
November 22, 2004
Nabil BELOUARDY
PhD Student @ ENST Paris
& EUROCONTROL Experimental Centre
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EUROCONTROL EXPERIMENTAL CENTRE
Air Traffic Management system
ATS (Air Traffic Service)
Air
Traffic Control service
ATFM (Air Traffic Flow Management)
Demand
/ Capacity balance
ASM (Airspace Management)
Allocation
2
of airspace
EUROCONTROL EXPERIMENTAL CENTRE
Capacity values (ECIP 2004)
3
State
ACC
Code
Hourly movements
Austria
Vienna
LOVV
147
Eurocontrol
Maastricht UAC EDYY
258
France
Paris
LFFF
244
France
Marseilles
LFMM
210
Germany
Munich
EDMM
235
Germany
Karlsruhe UAC
EDUU
188
Italy
Rome
LIRR
186
Slovakia
Bratislava
LZBB
073
UK
London
EGTT
370
EUROCONTROL EXPERIMENTAL CENTRE
Area Control Centre (EGTTC ACC)
Cross
section

Longitudinal section
EG01LUW
EG02LUE
FL 310
EG25LMWU
EG26LMEU
FL 245
EG25LMWL
EG25LMEL
FL 195
Opening
Scheme
EGLMU
EGLUS
EGLMS
EGLMU
EG26LME
EG25LMW
00:00
4
05:30
13:00
21:00
24:00
EUROCONTROL EXPERIMENTAL CENTRE
Flight Plans

Point profile Time: Beacon: Route: FL


Airspace profile min: Airspace: max


1631:EGMIDFI:1631 1631:EGT1ACC:1652 1631:EGTTACC:1652
1631:EILOND:1652 1631:EGTTBNN:1637 1631:EGCCTC2:1646
1637:EGTTLAM:1641 1641:EGTTDAG:1646 1646:EGTTRED:1652
1646:EGCCTC1:1652 1652:EHEB000245:1712 1652:EHM1245:1701
1652:EHSECT4:1700 1656:EHAAFIRT:1712 1700:EHAMTMA:1712
1701:EHACOD:1704
ATFM regulation

5
1631:EGLL:EGLLBPK6F:000 1634:*1LON:EGLLBPK6F:060
1635:CHT:EGLLBPK6F:060 1638:BPK:M185:060 1640:TOTRI:M185:134
1641:MATCH:M185:147 1643:BRAIN:M185:207 1644:DAGGA:M185:210
1644:*6CLN:M185:210 1645:CLN:L620:210 1647:ARTOV:L620:210
1652:REDFA:EHAMREDFA10:210 1657:SULUT:EHAMREDFA10:175
1700:SUGOL:EHAMREDFA10:100 1705:*SPL:EHAMREDFA10:070
1712:EHAM:EHAMREDFA10:000
Possible delay if flights across some ATC unit exceed capacity.
EUROCONTROL EXPERIMENTAL CENTRE
Need for ATFM regulation

6
Demand exceeds available capacity in some periods
EUROCONTROL EXPERIMENTAL CENTRE
Computer Assisted Slot Allocation
Take-off time
Dynamic and deterministic algorithm:
 3 hours before requested take-off time





No more delay will be affected
Delay can only decrease
T0 – 2 h
 t2

Slot is allocated for take-off
T0 – ½ h
t
Uncertainties


Will the aircraft take its slot ?
Will the crossed sectors be congestion-free?
T0
7
T0 – 3 h
 t1
½ an hour before take-off


No change in Flight Plan is possible
Delay affected = Argmax (regulations)
2 hours before take-off



t2 var t1 var
t2 (T0 – ½ h)
t1 (T0 – 2 h)
EUROCONTROL EXPERIMENTAL CENTRE
Efficiency of ATFM regulation

8
Collapsed sectors (groups) still suffer from over-delivery
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Why ?
Hypotheses
 Uncertainties
 If
all aircraft take off at its slot, regulation of CASA
will be fulfilled

Severe weather
 New

Nonconformity of Capacity with Opening Scheme
 No

flight paths result from re-routing
warranty for constraints satisfaction
Aircraft failure to respect Air Traffic rules
 Irregularities
9
in traffic shape
EUROCONTROL EXPERIMENTAL CENTRE
Uncertainties
ZOOM

Period of 09:00 -13:00
 Average
uncertainty on EOT is close to zero
 Standard deviation is less than 10 minutes
 Small center, crossed in almost 10 minutes
 Can’t generate130% of capacity (depicted by black color)
10
EUROCONTROL EXPERIMENTAL CENTRE
Weather

Jet Stream

Physical routes can be shift (traffic variability)
 Aircraft
coming from America are not concerned
Arr United
Central
Dep
States Canada America
United
States
11
0
0
0
Northern
Europe
3
Southern
Europe
else
0
0
Canada
0
0
0
0
0
0
Central
America
0
0
0
0
0
0
Northern
Europe
6
2
0
58
67
7
Southern
Europe
0
0
0
7
0
0
else
0
0
0
2
0
0
Distribution of
aircraft that
have eerie
flight plans
according to
Departure
and Arrival
areas
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ACC Capacity vs. Opening Scheme
Traffic load in opened groups
(Filed configuration)
 Bad from 13:00 to 21:00

12
Actual configuration ?
EUROCONTROL EXPERIMENTAL CENTRE
ACC Capacity vs. Opening Scheme

Final demand and Regulated traffic curves are
almost identical, no obvious limitation
 Flight
demands comply with ACC capacity
constraints

At collapsed sector level, capacity of activated
groups are exceeded
 Regulation
at a Macro level (Centre) does not insure
a safe flow at micro level (Opening scheme)

Trade-Off: Over-flow / Delay
 Adaptive
optimization of Opening Scheme to the
observed traffic
 Control of used ACC capacity value to prevent the
congestion in groups
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EUROCONTROL EXPERIMENTAL CENTRE
Stochastic pre-tactical planning
Other traffic shapes of other
sub-centers of London EGTT
shows
 Compliance between Final
demand and Regulated traffic

No excessive demand
Compliance between
Regulated and Current traffic


Smoothed uncertainty
No need for stochastic
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EUROCONTROL EXPERIMENTAL CENTRE
Conclusion
Over-delivery / Total delay trade-off
 Consistency problem between Macro / Micro layers

 Will
be investigated
 Possible if demand grows as fast as airspace resource
improvement

If demand continue increasing while capacity remains
steady
 Regulation
by ATFM delay will reach saturation
 Less aircraft are to be controlled if Long range flights are
isolated in a kind of uncontrolled highways (like over the
oceans)
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THE END
Thank you
for
your attention
Questions ?

16
EUROCONTROL EXPERIMENTAL CENTRE