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Monte Carlo comes to Rome: a note on the estimation of unconstrained runway capacity at Rome Fiumucino International Airport
Journal of Air Transport Management 5 (1999) 185}192
Monte Carlo comes to Rome: a note on the estimation of unconstrained runway capacity at Rome Fiumucino International Airport D.E. Pit"eld!,*, E.A. Jerrard" !Department of Civil and Building Engineering, Centre for Transport Studies, Loughborough University, Loughborough, Leicestershire LE 11 3 TU, UK "International Air Transport Association, 350 Avenue Louise, B-1050 Brussels, Belgium
Abstract A new airport capacity concept has been advanced by the International Air Transport Association (IATA). Unconstrained capacity represents the airport capacity with reservoirs of tra$c always available and the use of all planned technological and air tra$c managerial improvements. To establish its utility and estimate its value for the "rst time, the case of Rome Fiumucino International Airport is examined. ( 1999 Elsevier Science Ltd. All rights reserved. Keywords: Monte-Carlo simulation; Runway utilisation; Unconstrained capacity
1. Introduction
2. New capacity de5nitions
IATA has been engaged in a capacity study at Rome Fiumucino International Airport. As part of these studies, a new concept of capacity has been de"ned, which can be used in planning to draw conclusions by comparison with existing capacity measures, including those derived from simulation software, actual #ow totals and declared capacity. This note outlines the methodology used to derive estimates of this new capacity concept and details the results for three alternative scenarios describing different possible runway uses covering full-mix mode operations, partial mixed mode operations and managed departures. In Section 2, the new capacity de"nitions are outlined including the unconstrained capacity; the focus of this paper. In the next section, the parameters governing the simulation and the way in which these are applied to the estimation of capacity are described. Section 4 outlines the three alternative scenarios of runway usage before Section 5 details the simulations. Section 6 brings together the results and draws some conclusions on the usefulness of the approach taken.
The motivation behind the new de"nitions of capacity is an attempt to more closely relate actual and possible air tra$c movements to existing infrastructure and air tra$c control practises so as to better exploit existing infrastructure. If existing infrastructure can be better utilised, the need for expensive and lumpy infrastructure investment can at best be avoided, or at worst, postponed. In 1988 Eurocontrol1 established a database group for major airports in the European Civil Aviation Council (ECAC) states. A sub-group has been concerned to develop methods to assist in determining capacity assessment, in particular, to identify tools to establish capacity totals for alternative airport layouts so that like for like comparisons can be made2. This work is on-going but it is expected that completion will take place in 1999 when a formal Eurocontrol document will be issued. As a "rst step alternative capacity de"nitions have been advanced:
* Corresponding author. Tel.: 01509-223416; fax: 01509-223946. E-mail address: d.e.pit"[email protected] (D.E. Pit"eld)
1 The European Organisation for the Safety of Air Navigation, Brussels, Belgium. 2 At present it is the case that similar layouts can have declared capacities that vary by as much as 30% and more.
0969-6997/99/$ - see front matter ( 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 9 - 6 9 9 7 ( 9 9 ) 0 0 0 1 2 - 5
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f Declared capacity is the stated limiting capacity of the airport in aircraft movements per hour. f Sustained runway capacity is the maximum runway throughput, or #ow rate, which can be achieved over a sustained period of time when aircraft operate under instrument #ight rules (IFR), under a speci"c tra$c mix, in good weather conditions, with good air tra$c management (ATM)/runway system management, but in accordance with safety requirements and with an acceptable maximum delay3 for an agreed limited period of time. f Unconstrained runway capacity is the maximum runway throughput, or #ow rate, which can be achieved under ideal conditions, regardless of the level of service but in accordance with safety requirements. In the past when airports have used simulation models to undertake capacity assessments of the runway and associated airspace system, variables used have been based on accepted standards as used by air tra$c control (ATC) or pilot performance criteria observed at that particular aerodrome. The Federal Aviation Administration (FAA) have published runway capacity/delay "gures based on the majority of runway layouts (FAA, 1995) and these have been established as &best-in-class' using the FAA SIMMOD model. However, the &best-in-class' does not utilise all the ATC, ATM procedures and best pilot practices to maximise capacity. The unconstrained capacity is intended to use all these procedures and practices so that the airlines in conjunction with the airport authority can jointly determine what procedural or infrastructure improvements are necessary to reach this potential capacity "gure, at a cost that is acceptable and by contrast with the rather erratic building of infrastructure without any real-end bene"t such as at Milan Malpensa 2000 and the new Athens International airport.
3. Monte-Carlo simulation and the governing parameters Monte-Carlo simulation is a common tool for sampling from cumulative distributions until some steady state results. Descriptions of the technique can be found in standard texts such as Taha (1982) and an airport 3 Acceptable delays are those for which the airlines serving a particular airport can accept, both from a scheduling (time-table) or aircraft utilisation standpoint. The higher the delay, the greater the capacity and therefore the availability of additional &high value' slots, but at a cost, such as reduced aircraft utilisation and increased costs due to the delays at approximately $100 per minute. There is therefore a point at which costs exceed yield over the peak period being considered. At London Heathrow and London Gatwick the acceptable delay is 10 min, whereas at Amsterdam Schipol it is 4 min. However, the &unwritten' law used by IATA member airlines is that delays equal to or under 10 min are acceptable. The IATA Delay Code Guideline (IATA, 1999) shows the causes of reported delays equal to and over 15 min.
Table 1 ICAO arrival and separation rules (ICAO, 1996) For approaches (in distance)! A/C type Followed by: Heavy (n mile)
Followed by: Medium (n mile)
Followed by: Light (n mile)
Heavy Medium Light
5 2.5 2.5
6 5 2.5
For departures (in time) A/C type Followed by: Heavy (s)
Followed by: Medium (s)
Followed by: Light (s)
Heavy Medium Light
120 80 76
75 80 76
4 2.5 2.5
120 120 76
!To avoid wake turbulence.
application is reported in Pit"eld et al. (1998). However, in the case dealt with here there is no need for repeated simulations as the only random variable is the type of arriving and departing aircraft and their resulting order. The #eet mix is derived from a pre-determined distribution matching the tra$c mix experienced in the peak of summer 1997, this being 10% light, 70% medium and 20% heavy aircraft. This in turn in#uences the arrival and departure separations, governed by International Civil Aviation Organisation (ICAO) rules (see Table 1), and the runway occupancy time, taken as, respectively, 30, 40 and 50 s, respectively, as it is assumed that su$cient high speed runway exits exist to permit minimum runway occupancy times. The other parameters governing the estimation of unconstrained capacity are: f ATC have implemented ICAO and ECAC APATSI4 procedures and systems to support high intensity runway operations. f Visual meteorological conditions (VMC) prevail. f Prevalent wind condition as per Aeroporti di Roma's statistics giving northerly wind direction more than 96% of the time. f No signi"cant cross wind and tail wind components. f Divergent standard instrument departure routes are promulgated to permit minimum time sequencing between departures. f Departure runway occupancy times do not exceed 50 s from start to roll. ATC now give conditional departure clearance when aircraft enter a runway and this means that the aircraft, rather than stopping, roll slowly on to
4 European Civil Aviation Council/Airport and Air Tra$c System Interface (ECAC/APATSI, 1995).
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
187
Fig. 2. Proposed runway utilisation: scenario 1.
Fig. 1. Rome Fiumicino Airport Layout (This plan is from Eurocontrol (1997)).
the runway and then down the centreline. Studies5 have shown that occupancy times are below 50 s and that separations for subsequent departures are of the order of 60 s. f A &reservoir' of aircraft are available in the arrival or departure hold. The airlines endorse arrival holds as a best practice air tra$c management technique. The purpose of these holds are not only to act as a reservoir of aircraft to maximise runway utilisation, but also to provide streams of identical aircraft types (i.e. light, medium) over 10 min intervals6. This 10 min rule maximises arriving aircraft for the given ICAO separation rules, as shown in Table 1, and is in use at London Heathrow and London Gatwick and will soon be introduced in Barcelona and Madrid. f Taxiways and apron capacity is su$cient not to present any constraint.
4. Scenarios of runway use. Fig. 1 shows the runway layout at Rome Fiumucino International Airport.
5 IATA studies on High Intensity Runway Occupancy (HIRO), for example, at Madrid, Barcelona and Stockholm during 1998}1999. 6 See p.3 note 3 on acceptable delays.
Fig. 3. Proposed runway utilisation: scenario 2.
Figs. 2}4 show schematics for the three alternative use scenarios. In scenario 1 for full-mix mode operations there are arrivals on 16L, 16R and 25 with departures on the same runways. Arrivals on 25 and 16R would perform proposed ICAO simultaneous intersecting runway operations (SIRO) or FAA Land and Hold Short Operations (LAHSO)7 where runway 25 would be considered the secondary runway and 16R, the primary runway. ICAO rules permit independent instrument runway operations on 16R and 16L as they are greater than 2800 m apart. In scenario 2 for partial mixed mode operations, there are arrivals on 16L and 16R, with departures on 16L,
7 ICAO (1998), FAA (1999).
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Fig. 4. Proposed runway utilisation: scenario 3.
16R and 25. Scenario 3 has arrivals on 16L and 16R with managed departures of light aircraft on 16R, south of the runway 25/16L intersection8, medium aircraft on 25 and heavy aircraft on 16L. The declared capacity for these runways when this study was conducted in late 1998 was 70 movements/h9. In the peak of June 1998, between 15 and 16.00 h, the total movements were 55.
times are then compared to the simulated schedule of departing aircraft on the same runway. These departures can then be allocated to the runway vacant clock times and the delay to the schedule calculated. Where there are two uses of a runway (i.e. "rst arrivals and then departures), practically all of the scheduled departures can usually be accommodated if all su$cient vacant times, irrespective of duration, are used. That is, no account is taken of possible errors or delays that might mean that a tight departure slot cannot be used. This is reasonable, given that we are concerned with unconstrained capacity. Note that no departures are brought forward in time, so a few runway vacant slots are not used. So, the count of the accommodated departing aircraft gives the total per runway which is very close to or the same as the unconstrained simulated total. Where a third stream of aircraft is required to use the runway after the allocation of "rst arrivals and then departures, clearly the remaining vacant times after the "rst two uses are few and they may also be of a very short duration and so unusable. Consequently, when this third stream of simulated #ows is examined to see how many of the total can be accommodated, the result is inevitably a total much reduced from the original. So, a count of the number of aircraft that can be accommodated within the hour gives the total. The delays su!ered to the original schedule become progressively bigger so that the mean delay time is a fairly large number, re#ecting the later, larger delays. By the time this third stream is accommodated, the runway is e!ectively fully used.
5. The simulations
5.1. Scenario 1
For each runway, both arrival and departure movements are simulated for 1 h. This involves taking into account minimum separation distances for arrivals between di!erent aircraft types, all assumed to be travelling at 170 knots10, and minimum separation times for departures11, again depending on aircraft types. Once the cumulative event time reaches over 60 min, the simulation is stopped and the number of aircraft counted. As arrivals have priority, this count gives the arrival totals for each runway. It is possible for each arrival to determine both the clock time that the runway is occupied and the time that the runway is vacant. These vacant
It can be seen that there are three arrival streams and three departure streams and it is taken that arrivals have priority over departures. The random simulation of a mixed aircraft-type stream of arrivals on 16R gives a total of 33 in the peak hour as shown in Table 2. For arrivals on 16L and 7}25 not to con#ict they need to arrive on the runways at the same time12; therefore, the simulations for both of these two streams are identical (see Table 3) with the same time pro"le of aircraft types and associated minimum separations. This gives 32 arrivals on both runways; an arrival total of 97 per hour. Departures on 16L can only take place when 16L is not occupied by arrivals. Similarly, departures on 7}25 can only occur when there are no arrivals on 7}25 or on 16R. Finally, departures on 16R can only occur when there are no arrivals on 16R or departures on 7}25, where these last departures have priority over departures on 16R. When modelled, it can be shown that all of the 26 potential departing aircraft (see Table 4) on 16L can depart within the hour. The range of delay is from 0 to
8 Thereby eliminating dependency between simultaneous departures on those runways. 9 IATA Scheduling Conference, Berlin, November 1998. 10 Speeds at the Outer Marker are published in the Italian Aeronautical Information Publication (AIP), as required by ICAO, at between 160 and 180 knots, that is an average indicated air speed of 170 knots. 11 With "ve divergent departure tracks at each runway end, ICAO rules can apply on timing between successive departures, that is 1 min for same category and 2 min for di!erent categories. ATM techniques will minimise any mixing of aircraft categories on departure.
12 proposed SIRO operations.
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
189
Table 2 Arrival simulations for the peak hour on 16R Random no.
A/C type
Separation
Time from runway (mins)
Time on runway (secs)
Event duration (mins)
Cumulative time from 0 (start)
Cumulative time from 0 (end event)
Runway Duration vacant clock time
Vacant end time
0.6813601 0.8488842 0.1027797 0.6103501 0.4596117 0.0579582 0.4184349 0.6602035 0.0701741 0.390782 0.0814714 0.3423085 0.0229166 0.2754985 0.8820078 0.4098126 0.9807814 0.4652143 0.0813989 0.6301415 0.8309442 0.9145744 0.2466144 0.2108625 0.092112 0.8428244 0.5900325 0.9202214 0.7052173 0.150817 0.3847457 0.7991219 0.3879563
M M H M M L M M L M L M L H M M M M L M M M H H L M M M M H M M M
2.5 2.5 5 2.5 5 2.5 2.5 5 2.5 5 2.5 5 2.5 5 2.5 2.5 2.5 5 2.5 2.5 2.5 2.5 4 6 2.5 2.5 2.5 2.5 2.5 5 2.5 2.5 2.5
0.88 0.88 1.76 0.88 1.76 0.88 0.88 1.76 0.88 1.76 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.76 0.88 0.88 0.88 0.88 1.41 2.12 0.88 0.88 0.88 0.88 0.88 1.76 0.88 0.88 0.88
40 40 50 40 40 30 40 40 30 40 30 40 30 50 40 40 40 40 30 40 40 40 50 50 30 40 40 40 40 50 40 40 40
1.55 1.55 2.60 1.55 2.43 1.38 1.55 2.43 1.38 2.43 1.38 2.43 1.38 2.60 1.55 1.55 1.55 2.43 1.38 1.55 1.55 1.55 2.25 2.95 1.38 1.55 1.55 1.55 1.55 2.60 1.55 1.55 1.55
0.00 1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 38.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23
1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 36.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23 59.77
0.00 1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 38.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23
0.88 2.43 4.86 6.58 9.01 10.56 11.94 14.37 15.92 18.19 19.74 22.00 23.55 25.81 27.53 29.08 30.63 33.06 34.61 35.99 37.54 39.09 41.17 44.12 45.83 47.22 48.76 50.31 51.86 54.29 56.01 57.56 59.11
1.76 min with a mean of 0.70. The greater con#ict for departures on 7}25 only allows the "rst 15 movements shown in Table 5 with a delay ranging from 0 to 27.92 min and a mean delay of 15.13 min. For 16R (see Table 6), 21 of the departures can be facilitated when there are no arrivals on 16R or departures on 7}25. Compared to the original unconstrained departure schedule there is a delay ranging from 1.55 to 12.47 min with a mean of 6.54. Therefore, departures total 62, giving total arrivals and departures in the hour of 159. If departures, however, were to require gaps greater or equal to 1 min, then the number of departures would be considerably reduced to something like 15.
0.88 0.88 1.76 0.88 1.76 0.88 0.88 1.76 0.88 1.76 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.76 0.88 0.88 0.88 0.88 1.41 2.12 0.88 0.88 0.88 0.88 0.88 1.76 0.88 0.88 0.88
await vacancies on 16L from arrivals whilst departures on 7}25 only have to await non-use of 16R by arrivals. Departures on 16R use the time slots that remain after the usage for arrivals and the con#ict with departures on 7}25. The simulations give 34 arrivals on 16R and 33 on 16L,13 a total of 67. Departures on 16L total 26 with a delay ranging from 0 to 1.91 min with a mean of 0.81. On 7}25, departures total 25 with a delay range of 0}1.46 min and a mean of 0.75. Departures on 16R total 14 in the hour, ranging in delay times from the unconstrained schedule of 1.38}26.7 min with a mean of 13.25 min. This gives total departures as 65 and total movements as 132. However, if departure gaps of a minute or greater were required, then the departure total would reduce to 17.
5.2. Scenario 2 This is a simpler case to model. Two randomly mixed arrival streams are required for 16R and 16L, along with three departure streams. Departures on 16L only have to
13 It was felt that further tables illustrating the simulation would add little to what has been shown for the previous scenario, so none are shown here or for scenario 3.
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Table 3 Arrival simulations for the peak hour on 16L and 7}25 Random no.
A/C type
Separation
0.3267633 0.353228 0.5805979 0.2636805 0.8176407 0.2604956 0.5387673 0.4450646 0.1910004 0.0263031 0.5340608 0.2229296 0.6033523 0.734629 0.0027812 0.5250686 0.9104893 0.1267739 0.2574994 0.1132904 0.8366629 0.0779173 0.4366561 0.6110804 0.631658 0.724225 0.8251326 0.838446 0.5897236 0.8863521 0.0749394 0.1913065
M M M H M H M M H L M H M M L M M H H H M L M M M M M M M M L H
2.5 2.5 2.5 5 2.5 5 2.5 2.5 6 2.5 2.5 5 2.5 5 2.5 2.5 2.5 4 4 5 5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 5 2.5 6
Time from runway (mins) 0.88 0.88 0.88 1.76 0.88 1.76 0.88 0.88 2.12 0.88 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.41 1.41 1.76 1.76 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 1.76 0.88 2.12
Time on runway (secs)
Event duration (mins)
Cumulative time from 0 (start)
Cumulative time from 0 (end event)
Runway Duration vacant clock time
Vacant end time
40 40 40 50 40 50 40 40 50 30 40 50 40 40 30 40 40 50 50 50 40 30 40 40 40 40 40 40 40 40 30 50
1.55 1.55 1.55 2.60 1.55 2.60 1.55 1.55 2.95 1.38 1.55 2.60 1.55 2.43 1.38 1.55 1.55 2.25 2.25 2.60 2.43 1.38 1.55 1.55 1.55 1.55 1.55 1.55 1.55 2.43 1.38 2.95
0.00 1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99
1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99 59.94
0.00 1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99
0.88 2.43 3.98 6.41 8.13 10.56 12.27 13.82 16.61 18.32 19.71 22.14 23.85 26.28 27.83 29.22 30.76 32.84 35.09 37.69 40.28 41.83 43.22 44.76 46.31 47.86 49.41 50.98 52.51 54.94 56.49 59.11
0.88 0.88 0.88 1.76 0.88 1.76 0.88 0.88 2.12 0.88 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.41 1.41 1.76 1.76 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 1.76 0.88 2.12
5.3. Scenario 3
6. Conclusion
As with the previous case, two randomly mixed arrival streams are required for 16R and 16L, along with three departure streams but now these departures are dedicated by aircraft type. Light aircraft use 16R; Heavy aircraft use 16L and Medium use 7}25. So Heavy departures on 16L have to await gaps between arrivals on the same runway and Medium departures on 7}25 must not con#ict with arrivals on 16R. The results for this case give 33 arrivals on 16R and 32 on 16L, a total of 65. Departures on 16L total 29 with a delay ranging from 0 to 2.43 min with a mean of 0.72. On 7}25, medium departures total 28 with a mean delay of 0.70 min and a range of 0}1.42. Light departures on 16R total 29 aircraft. This gives total departures as 86 and total movements as 151. If the same caveat was invoked on the size of departure slots, they would reduce to 52.
Table 7 below summarises the unconstrained capacity estimates for the three scenarios. Clearly, scenario 1 bene"ts from the additional arrival stream but this constrains, in particular, the departures on 7}25. This would be less so if all three arrival streams were taken as identical. If departures on 7}25 are only singly restricted, as in scenario 2, then they increase in number whilst departures on 16R fall. Segregating departures by aircraft type increases the runway capacity as scenario 3 shows. It may be the case that maximum use of the runways would be realised if this scenario allowed for a third arrival stream. This paper has de"ned a new concept of airport capacity and demonstrated a methodology to derive an estimate of this value. This value has been compared to alternative capacity concepts and the di!erences can
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
191
Table 4 Departure simulations for the peak hour on 16L Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.740845 0.162563 0.340999 0.492122 0.992368 0.605721 0.000346 0.357681 0.53662 0.71605 0.56201 0.713405 0.071429 0.043973 0.404932 0.831809 0.653866 0.368643 0.430929 0.281664 0.726613 0.419562 0.463823 0.984345 0.495242 0.575225
M H M M M M L M M M M M L L M M M M M H M M M M M M
80 120 80 80 80 120 76 80 80 80 80 120 76 76 80 80 80 80 80 120 80 80 80 80 80 80
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.17 2.83 2.17 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.83 2.10 2.10 2.17 2.17 2.17 2.17 2.17 2.83 2.17 2.17 2.17 2.17 2.17 2.17
0.00 2.17 5.00 7.17 9.33 11.50 14.33 16.43 18.60 20.77 22.93 25.10 27.93 30.03 32.13 34.30 36.47 38.63 40.80 42.97 45.80 47.97 50.13 52.30 54.47 56.63
2.17 5.00 7.17 9.33 11.50 14.33 16.43 18.60 20.77 22.93 25.10 27.93 30.03 32.13 34.30 36.47 38.63 40.80 42.97 45.80 47.97 50.13 52.30 54.47 56.63 58.80
Table 5 Departure simulations for the peak hour on 7}25 Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.17473 0.096426 0.584959 0.648445 0.936607 0.785839 0.697034 0.418846 0.575523 0.437569 0.33726 0.866116 0.121337 0.009868 0.5486 0.277399 0.422571 0.558315 0.209892 0.017921 0.805397 0.847327 0.921865 0.353397 0.136559 0.46858
H L M M M M M M M M M M H L M H M M H L M M M M H M
120 76 80 80 80 80 80 80 80 80 80 80 120 76 80 120 80 80 120 76 80 80 80 80 120 80
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.83 2.10 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.83 2.10 2.17 2.83 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.83 2.17
0.00 2.83 4.93 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 29.43 31.53 33.70 36.53 38.70 40.87 43.70 45.80 47.97 50.13 52.30 54.47 57.30
2.83 4.93 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 29.43 31.53 33.70 36.53 38.70 40.87 43.70 45.80 47.97 50.13 52.30 54.47 57.30 59.47
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Table 6 Departure simulations for the peak hour on 16R Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.862456 0.876266 0.060652 0.657453 0.311012 0.687109 0.755674 0.693671 0.840188 0.733594 0.825936 0.944366 0.361341 0.600667 0.65873 0.516694 0.813899 0.322635 0.078211 0.787992 0.421401 0.723064 0.15187 0.171769 0.637507 0.150843
M M L M M M M M M M M M M M M M M M L M M M H H M H
80 120 76 80 80 80 80 80 80 80 80 80 80 80 80 80 80 120 76 80 80 80 75 120 80 75
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.08 2.83 2.17 2.08
0.00 2.17 5.00 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 28.77 30.93 33.10 35.27 37.43 40.27 42.37 44.53 46.70 48.87 50.95 53.78 55.95
2.17 5.00 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 28.77 30.93 33.10 35.27 37.43 40.27 42.37 44.53 46.70 48.87 50.95 53.78 55.95 58.03
References
Table 7 Unconstrained runway capacity: scenarios 1}3 Scenarios
Arrivals 16R Arrivals 16L Arrivals 7}25 Departures 16R Departures 16L Departures 7}25 Totals Hourly air tra$c movement range
1
2
3
33 32 32 21 26 15
34 33 * 14 26 25
33 32 * 29 29 28
159 112}159
132 84}132
151 117}151
allow the identi"cation of crucial parameters, the variation in which may enable the postponement or abandonment of expensive airport infrastructure investment whilst still enabling increasing air transport demand to be safely met. Indeed, as a result of the work reported here the declared capacity at Rome Fiumucino International Airport will be increased to 84 movements per hour from the winter schedule, 1999 and the proposed fourth runway, planned for 2005 when movements reached 80 per hour, has been shelved.
ECAC/APATSI, 1995. Manual of Mature Air Tra$c Procedures. ECAC, Paris. Eurocontrol, 1997. European Database of Major Airports in the ECAC States. 1996 Annual Report, Brussels, Belgium. FAA, 1995. Airport Capacity and Delay. Advisory Circular 150/5060-5, US Department of Transportation, Washington. FAA, 1999. Land and Hold Short Operations (LAHSO). N7110.199, US Department of Transportation, Washington. IATA, 1999. Airport Ground Handling Manual, 19th Edition. Geneva, Switzerland/ Montreal, Canada. ICAO, 1996. Procedures for Air Navigation Services. Rules of the Air and Air Tra$c Services, 13th Edition Doc. 4444-RAC/50, ICAO, Paris. ICAO, 1998. RCM and Guidance Material on Simultaneous Intersecting Runway Operations. Proposal for amendments of the ICAO EUR Air Navigation Plan, Serial No.EUR/NAT 98/12-AOP-RCM & GM (Rev.2), ICAO, Paris. Pit"eld, D.E., Brooke, A.S., Jerrard, E.A., 1998. A Monte-Carlo simulation of potentially con#icting ground movements at a new international airport. Journal of Air Transport Management 4, 3}9. Taha, H.A., 1982. Operations Research. Collier Macmillan, New York.
Monte Carlo comes to Rome: a note on the estimation of unconstrained runway capacity at Rome Fiumucino International Airport D.E. Pit"eld!,*, E.A. Jerrard" !Department of Civil and Building Engineering, Centre for Transport Studies, Loughborough University, Loughborough, Leicestershire LE 11 3 TU, UK "International Air Transport Association, 350 Avenue Louise, B-1050 Brussels, Belgium
Abstract A new airport capacity concept has been advanced by the International Air Transport Association (IATA). Unconstrained capacity represents the airport capacity with reservoirs of tra$c always available and the use of all planned technological and air tra$c managerial improvements. To establish its utility and estimate its value for the "rst time, the case of Rome Fiumucino International Airport is examined. ( 1999 Elsevier Science Ltd. All rights reserved. Keywords: Monte-Carlo simulation; Runway utilisation; Unconstrained capacity
1. Introduction
2. New capacity de5nitions
IATA has been engaged in a capacity study at Rome Fiumucino International Airport. As part of these studies, a new concept of capacity has been de"ned, which can be used in planning to draw conclusions by comparison with existing capacity measures, including those derived from simulation software, actual #ow totals and declared capacity. This note outlines the methodology used to derive estimates of this new capacity concept and details the results for three alternative scenarios describing different possible runway uses covering full-mix mode operations, partial mixed mode operations and managed departures. In Section 2, the new capacity de"nitions are outlined including the unconstrained capacity; the focus of this paper. In the next section, the parameters governing the simulation and the way in which these are applied to the estimation of capacity are described. Section 4 outlines the three alternative scenarios of runway usage before Section 5 details the simulations. Section 6 brings together the results and draws some conclusions on the usefulness of the approach taken.
The motivation behind the new de"nitions of capacity is an attempt to more closely relate actual and possible air tra$c movements to existing infrastructure and air tra$c control practises so as to better exploit existing infrastructure. If existing infrastructure can be better utilised, the need for expensive and lumpy infrastructure investment can at best be avoided, or at worst, postponed. In 1988 Eurocontrol1 established a database group for major airports in the European Civil Aviation Council (ECAC) states. A sub-group has been concerned to develop methods to assist in determining capacity assessment, in particular, to identify tools to establish capacity totals for alternative airport layouts so that like for like comparisons can be made2. This work is on-going but it is expected that completion will take place in 1999 when a formal Eurocontrol document will be issued. As a "rst step alternative capacity de"nitions have been advanced:
* Corresponding author. Tel.: 01509-223416; fax: 01509-223946. E-mail address: d.e.pit"[email protected] (D.E. Pit"eld)
1 The European Organisation for the Safety of Air Navigation, Brussels, Belgium. 2 At present it is the case that similar layouts can have declared capacities that vary by as much as 30% and more.
0969-6997/99/$ - see front matter ( 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 9 - 6 9 9 7 ( 9 9 ) 0 0 0 1 2 - 5
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f Declared capacity is the stated limiting capacity of the airport in aircraft movements per hour. f Sustained runway capacity is the maximum runway throughput, or #ow rate, which can be achieved over a sustained period of time when aircraft operate under instrument #ight rules (IFR), under a speci"c tra$c mix, in good weather conditions, with good air tra$c management (ATM)/runway system management, but in accordance with safety requirements and with an acceptable maximum delay3 for an agreed limited period of time. f Unconstrained runway capacity is the maximum runway throughput, or #ow rate, which can be achieved under ideal conditions, regardless of the level of service but in accordance with safety requirements. In the past when airports have used simulation models to undertake capacity assessments of the runway and associated airspace system, variables used have been based on accepted standards as used by air tra$c control (ATC) or pilot performance criteria observed at that particular aerodrome. The Federal Aviation Administration (FAA) have published runway capacity/delay "gures based on the majority of runway layouts (FAA, 1995) and these have been established as &best-in-class' using the FAA SIMMOD model. However, the &best-in-class' does not utilise all the ATC, ATM procedures and best pilot practices to maximise capacity. The unconstrained capacity is intended to use all these procedures and practices so that the airlines in conjunction with the airport authority can jointly determine what procedural or infrastructure improvements are necessary to reach this potential capacity "gure, at a cost that is acceptable and by contrast with the rather erratic building of infrastructure without any real-end bene"t such as at Milan Malpensa 2000 and the new Athens International airport.
3. Monte-Carlo simulation and the governing parameters Monte-Carlo simulation is a common tool for sampling from cumulative distributions until some steady state results. Descriptions of the technique can be found in standard texts such as Taha (1982) and an airport 3 Acceptable delays are those for which the airlines serving a particular airport can accept, both from a scheduling (time-table) or aircraft utilisation standpoint. The higher the delay, the greater the capacity and therefore the availability of additional &high value' slots, but at a cost, such as reduced aircraft utilisation and increased costs due to the delays at approximately $100 per minute. There is therefore a point at which costs exceed yield over the peak period being considered. At London Heathrow and London Gatwick the acceptable delay is 10 min, whereas at Amsterdam Schipol it is 4 min. However, the &unwritten' law used by IATA member airlines is that delays equal to or under 10 min are acceptable. The IATA Delay Code Guideline (IATA, 1999) shows the causes of reported delays equal to and over 15 min.
Table 1 ICAO arrival and separation rules (ICAO, 1996) For approaches (in distance)! A/C type Followed by: Heavy (n mile)
Followed by: Medium (n mile)
Followed by: Light (n mile)
Heavy Medium Light
5 2.5 2.5
6 5 2.5
For departures (in time) A/C type Followed by: Heavy (s)
Followed by: Medium (s)
Followed by: Light (s)
Heavy Medium Light
120 80 76
75 80 76
4 2.5 2.5
120 120 76
!To avoid wake turbulence.
application is reported in Pit"eld et al. (1998). However, in the case dealt with here there is no need for repeated simulations as the only random variable is the type of arriving and departing aircraft and their resulting order. The #eet mix is derived from a pre-determined distribution matching the tra$c mix experienced in the peak of summer 1997, this being 10% light, 70% medium and 20% heavy aircraft. This in turn in#uences the arrival and departure separations, governed by International Civil Aviation Organisation (ICAO) rules (see Table 1), and the runway occupancy time, taken as, respectively, 30, 40 and 50 s, respectively, as it is assumed that su$cient high speed runway exits exist to permit minimum runway occupancy times. The other parameters governing the estimation of unconstrained capacity are: f ATC have implemented ICAO and ECAC APATSI4 procedures and systems to support high intensity runway operations. f Visual meteorological conditions (VMC) prevail. f Prevalent wind condition as per Aeroporti di Roma's statistics giving northerly wind direction more than 96% of the time. f No signi"cant cross wind and tail wind components. f Divergent standard instrument departure routes are promulgated to permit minimum time sequencing between departures. f Departure runway occupancy times do not exceed 50 s from start to roll. ATC now give conditional departure clearance when aircraft enter a runway and this means that the aircraft, rather than stopping, roll slowly on to
4 European Civil Aviation Council/Airport and Air Tra$c System Interface (ECAC/APATSI, 1995).
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
187
Fig. 2. Proposed runway utilisation: scenario 1.
Fig. 1. Rome Fiumicino Airport Layout (This plan is from Eurocontrol (1997)).
the runway and then down the centreline. Studies5 have shown that occupancy times are below 50 s and that separations for subsequent departures are of the order of 60 s. f A &reservoir' of aircraft are available in the arrival or departure hold. The airlines endorse arrival holds as a best practice air tra$c management technique. The purpose of these holds are not only to act as a reservoir of aircraft to maximise runway utilisation, but also to provide streams of identical aircraft types (i.e. light, medium) over 10 min intervals6. This 10 min rule maximises arriving aircraft for the given ICAO separation rules, as shown in Table 1, and is in use at London Heathrow and London Gatwick and will soon be introduced in Barcelona and Madrid. f Taxiways and apron capacity is su$cient not to present any constraint.
4. Scenarios of runway use. Fig. 1 shows the runway layout at Rome Fiumucino International Airport.
5 IATA studies on High Intensity Runway Occupancy (HIRO), for example, at Madrid, Barcelona and Stockholm during 1998}1999. 6 See p.3 note 3 on acceptable delays.
Fig. 3. Proposed runway utilisation: scenario 2.
Figs. 2}4 show schematics for the three alternative use scenarios. In scenario 1 for full-mix mode operations there are arrivals on 16L, 16R and 25 with departures on the same runways. Arrivals on 25 and 16R would perform proposed ICAO simultaneous intersecting runway operations (SIRO) or FAA Land and Hold Short Operations (LAHSO)7 where runway 25 would be considered the secondary runway and 16R, the primary runway. ICAO rules permit independent instrument runway operations on 16R and 16L as they are greater than 2800 m apart. In scenario 2 for partial mixed mode operations, there are arrivals on 16L and 16R, with departures on 16L,
7 ICAO (1998), FAA (1999).
188
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Fig. 4. Proposed runway utilisation: scenario 3.
16R and 25. Scenario 3 has arrivals on 16L and 16R with managed departures of light aircraft on 16R, south of the runway 25/16L intersection8, medium aircraft on 25 and heavy aircraft on 16L. The declared capacity for these runways when this study was conducted in late 1998 was 70 movements/h9. In the peak of June 1998, between 15 and 16.00 h, the total movements were 55.
times are then compared to the simulated schedule of departing aircraft on the same runway. These departures can then be allocated to the runway vacant clock times and the delay to the schedule calculated. Where there are two uses of a runway (i.e. "rst arrivals and then departures), practically all of the scheduled departures can usually be accommodated if all su$cient vacant times, irrespective of duration, are used. That is, no account is taken of possible errors or delays that might mean that a tight departure slot cannot be used. This is reasonable, given that we are concerned with unconstrained capacity. Note that no departures are brought forward in time, so a few runway vacant slots are not used. So, the count of the accommodated departing aircraft gives the total per runway which is very close to or the same as the unconstrained simulated total. Where a third stream of aircraft is required to use the runway after the allocation of "rst arrivals and then departures, clearly the remaining vacant times after the "rst two uses are few and they may also be of a very short duration and so unusable. Consequently, when this third stream of simulated #ows is examined to see how many of the total can be accommodated, the result is inevitably a total much reduced from the original. So, a count of the number of aircraft that can be accommodated within the hour gives the total. The delays su!ered to the original schedule become progressively bigger so that the mean delay time is a fairly large number, re#ecting the later, larger delays. By the time this third stream is accommodated, the runway is e!ectively fully used.
5. The simulations
5.1. Scenario 1
For each runway, both arrival and departure movements are simulated for 1 h. This involves taking into account minimum separation distances for arrivals between di!erent aircraft types, all assumed to be travelling at 170 knots10, and minimum separation times for departures11, again depending on aircraft types. Once the cumulative event time reaches over 60 min, the simulation is stopped and the number of aircraft counted. As arrivals have priority, this count gives the arrival totals for each runway. It is possible for each arrival to determine both the clock time that the runway is occupied and the time that the runway is vacant. These vacant
It can be seen that there are three arrival streams and three departure streams and it is taken that arrivals have priority over departures. The random simulation of a mixed aircraft-type stream of arrivals on 16R gives a total of 33 in the peak hour as shown in Table 2. For arrivals on 16L and 7}25 not to con#ict they need to arrive on the runways at the same time12; therefore, the simulations for both of these two streams are identical (see Table 3) with the same time pro"le of aircraft types and associated minimum separations. This gives 32 arrivals on both runways; an arrival total of 97 per hour. Departures on 16L can only take place when 16L is not occupied by arrivals. Similarly, departures on 7}25 can only occur when there are no arrivals on 7}25 or on 16R. Finally, departures on 16R can only occur when there are no arrivals on 16R or departures on 7}25, where these last departures have priority over departures on 16R. When modelled, it can be shown that all of the 26 potential departing aircraft (see Table 4) on 16L can depart within the hour. The range of delay is from 0 to
8 Thereby eliminating dependency between simultaneous departures on those runways. 9 IATA Scheduling Conference, Berlin, November 1998. 10 Speeds at the Outer Marker are published in the Italian Aeronautical Information Publication (AIP), as required by ICAO, at between 160 and 180 knots, that is an average indicated air speed of 170 knots. 11 With "ve divergent departure tracks at each runway end, ICAO rules can apply on timing between successive departures, that is 1 min for same category and 2 min for di!erent categories. ATM techniques will minimise any mixing of aircraft categories on departure.
12 proposed SIRO operations.
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
189
Table 2 Arrival simulations for the peak hour on 16R Random no.
A/C type
Separation
Time from runway (mins)
Time on runway (secs)
Event duration (mins)
Cumulative time from 0 (start)
Cumulative time from 0 (end event)
Runway Duration vacant clock time
Vacant end time
0.6813601 0.8488842 0.1027797 0.6103501 0.4596117 0.0579582 0.4184349 0.6602035 0.0701741 0.390782 0.0814714 0.3423085 0.0229166 0.2754985 0.8820078 0.4098126 0.9807814 0.4652143 0.0813989 0.6301415 0.8309442 0.9145744 0.2466144 0.2108625 0.092112 0.8428244 0.5900325 0.9202214 0.7052173 0.150817 0.3847457 0.7991219 0.3879563
M M H M M L M M L M L M L H M M M M L M M M H H L M M M M H M M M
2.5 2.5 5 2.5 5 2.5 2.5 5 2.5 5 2.5 5 2.5 5 2.5 2.5 2.5 5 2.5 2.5 2.5 2.5 4 6 2.5 2.5 2.5 2.5 2.5 5 2.5 2.5 2.5
0.88 0.88 1.76 0.88 1.76 0.88 0.88 1.76 0.88 1.76 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.76 0.88 0.88 0.88 0.88 1.41 2.12 0.88 0.88 0.88 0.88 0.88 1.76 0.88 0.88 0.88
40 40 50 40 40 30 40 40 30 40 30 40 30 50 40 40 40 40 30 40 40 40 50 50 30 40 40 40 40 50 40 40 40
1.55 1.55 2.60 1.55 2.43 1.38 1.55 2.43 1.38 2.43 1.38 2.43 1.38 2.60 1.55 1.55 1.55 2.43 1.38 1.55 1.55 1.55 2.25 2.95 1.38 1.55 1.55 1.55 1.55 2.60 1.55 1.55 1.55
0.00 1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 38.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23
1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 36.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23 59.77
0.00 1.55 3.10 5.70 7.25 9.68 11.06 12.61 15.04 16.42 18.85 20.24 22.67 24.05 26.65 28.20 29.75 31.29 33.73 35.11 36.66 38.21 39.75 42.00 44.95 46.33 47.88 49.43 50.98 52.53 55.13 56.68 58.23
0.88 2.43 4.86 6.58 9.01 10.56 11.94 14.37 15.92 18.19 19.74 22.00 23.55 25.81 27.53 29.08 30.63 33.06 34.61 35.99 37.54 39.09 41.17 44.12 45.83 47.22 48.76 50.31 51.86 54.29 56.01 57.56 59.11
1.76 min with a mean of 0.70. The greater con#ict for departures on 7}25 only allows the "rst 15 movements shown in Table 5 with a delay ranging from 0 to 27.92 min and a mean delay of 15.13 min. For 16R (see Table 6), 21 of the departures can be facilitated when there are no arrivals on 16R or departures on 7}25. Compared to the original unconstrained departure schedule there is a delay ranging from 1.55 to 12.47 min with a mean of 6.54. Therefore, departures total 62, giving total arrivals and departures in the hour of 159. If departures, however, were to require gaps greater or equal to 1 min, then the number of departures would be considerably reduced to something like 15.
0.88 0.88 1.76 0.88 1.76 0.88 0.88 1.76 0.88 1.76 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.76 0.88 0.88 0.88 0.88 1.41 2.12 0.88 0.88 0.88 0.88 0.88 1.76 0.88 0.88 0.88
await vacancies on 16L from arrivals whilst departures on 7}25 only have to await non-use of 16R by arrivals. Departures on 16R use the time slots that remain after the usage for arrivals and the con#ict with departures on 7}25. The simulations give 34 arrivals on 16R and 33 on 16L,13 a total of 67. Departures on 16L total 26 with a delay ranging from 0 to 1.91 min with a mean of 0.81. On 7}25, departures total 25 with a delay range of 0}1.46 min and a mean of 0.75. Departures on 16R total 14 in the hour, ranging in delay times from the unconstrained schedule of 1.38}26.7 min with a mean of 13.25 min. This gives total departures as 65 and total movements as 132. However, if departure gaps of a minute or greater were required, then the departure total would reduce to 17.
5.2. Scenario 2 This is a simpler case to model. Two randomly mixed arrival streams are required for 16R and 16L, along with three departure streams. Departures on 16L only have to
13 It was felt that further tables illustrating the simulation would add little to what has been shown for the previous scenario, so none are shown here or for scenario 3.
190
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Table 3 Arrival simulations for the peak hour on 16L and 7}25 Random no.
A/C type
Separation
0.3267633 0.353228 0.5805979 0.2636805 0.8176407 0.2604956 0.5387673 0.4450646 0.1910004 0.0263031 0.5340608 0.2229296 0.6033523 0.734629 0.0027812 0.5250686 0.9104893 0.1267739 0.2574994 0.1132904 0.8366629 0.0779173 0.4366561 0.6110804 0.631658 0.724225 0.8251326 0.838446 0.5897236 0.8863521 0.0749394 0.1913065
M M M H M H M M H L M H M M L M M H H H M L M M M M M M M M L H
2.5 2.5 2.5 5 2.5 5 2.5 2.5 6 2.5 2.5 5 2.5 5 2.5 2.5 2.5 4 4 5 5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 5 2.5 6
Time from runway (mins) 0.88 0.88 0.88 1.76 0.88 1.76 0.88 0.88 2.12 0.88 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.41 1.41 1.76 1.76 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 1.76 0.88 2.12
Time on runway (secs)
Event duration (mins)
Cumulative time from 0 (start)
Cumulative time from 0 (end event)
Runway Duration vacant clock time
Vacant end time
40 40 40 50 40 50 40 40 50 30 40 50 40 40 30 40 40 50 50 50 40 30 40 40 40 40 40 40 40 40 30 50
1.55 1.55 1.55 2.60 1.55 2.60 1.55 1.55 2.95 1.38 1.55 2.60 1.55 2.43 1.38 1.55 1.55 2.25 2.25 2.60 2.43 1.38 1.55 1.55 1.55 1.55 1.55 1.55 1.55 2.43 1.38 2.95
0.00 1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99
1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99 59.94
0.00 1.55 3.10 4.65 7.25 8.79 11.39 12.94 14.49 17.44 18.82 20.37 22.97 24.52 26.95 28.33 29.88 31.43 33.68 35.92 38.52 40.95 42.33 43.88 45.43 46.98 48.53 50.08 51.63 53.18 55.61 56.99
0.88 2.43 3.98 6.41 8.13 10.56 12.27 13.82 16.61 18.32 19.71 22.14 23.85 26.28 27.83 29.22 30.76 32.84 35.09 37.69 40.28 41.83 43.22 44.76 46.31 47.86 49.41 50.98 52.51 54.94 56.49 59.11
0.88 0.88 0.88 1.76 0.88 1.76 0.88 0.88 2.12 0.88 0.88 1.76 0.88 1.76 0.88 0.88 0.88 1.41 1.41 1.76 1.76 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 1.76 0.88 2.12
5.3. Scenario 3
6. Conclusion
As with the previous case, two randomly mixed arrival streams are required for 16R and 16L, along with three departure streams but now these departures are dedicated by aircraft type. Light aircraft use 16R; Heavy aircraft use 16L and Medium use 7}25. So Heavy departures on 16L have to await gaps between arrivals on the same runway and Medium departures on 7}25 must not con#ict with arrivals on 16R. The results for this case give 33 arrivals on 16R and 32 on 16L, a total of 65. Departures on 16L total 29 with a delay ranging from 0 to 2.43 min with a mean of 0.72. On 7}25, medium departures total 28 with a mean delay of 0.70 min and a range of 0}1.42. Light departures on 16R total 29 aircraft. This gives total departures as 86 and total movements as 151. If the same caveat was invoked on the size of departure slots, they would reduce to 52.
Table 7 below summarises the unconstrained capacity estimates for the three scenarios. Clearly, scenario 1 bene"ts from the additional arrival stream but this constrains, in particular, the departures on 7}25. This would be less so if all three arrival streams were taken as identical. If departures on 7}25 are only singly restricted, as in scenario 2, then they increase in number whilst departures on 16R fall. Segregating departures by aircraft type increases the runway capacity as scenario 3 shows. It may be the case that maximum use of the runways would be realised if this scenario allowed for a third arrival stream. This paper has de"ned a new concept of airport capacity and demonstrated a methodology to derive an estimate of this value. This value has been compared to alternative capacity concepts and the di!erences can
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
191
Table 4 Departure simulations for the peak hour on 16L Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.740845 0.162563 0.340999 0.492122 0.992368 0.605721 0.000346 0.357681 0.53662 0.71605 0.56201 0.713405 0.071429 0.043973 0.404932 0.831809 0.653866 0.368643 0.430929 0.281664 0.726613 0.419562 0.463823 0.984345 0.495242 0.575225
M H M M M M L M M M M M L L M M M M M H M M M M M M
80 120 80 80 80 120 76 80 80 80 80 120 76 76 80 80 80 80 80 120 80 80 80 80 80 80
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.17 2.83 2.17 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.83 2.10 2.10 2.17 2.17 2.17 2.17 2.17 2.83 2.17 2.17 2.17 2.17 2.17 2.17
0.00 2.17 5.00 7.17 9.33 11.50 14.33 16.43 18.60 20.77 22.93 25.10 27.93 30.03 32.13 34.30 36.47 38.63 40.80 42.97 45.80 47.97 50.13 52.30 54.47 56.63
2.17 5.00 7.17 9.33 11.50 14.33 16.43 18.60 20.77 22.93 25.10 27.93 30.03 32.13 34.30 36.47 38.63 40.80 42.97 45.80 47.97 50.13 52.30 54.47 56.63 58.80
Table 5 Departure simulations for the peak hour on 7}25 Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.17473 0.096426 0.584959 0.648445 0.936607 0.785839 0.697034 0.418846 0.575523 0.437569 0.33726 0.866116 0.121337 0.009868 0.5486 0.277399 0.422571 0.558315 0.209892 0.017921 0.805397 0.847327 0.921865 0.353397 0.136559 0.46858
H L M M M M M M M M M M H L M H M M H L M M M M H M
120 76 80 80 80 80 80 80 80 80 80 80 120 76 80 120 80 80 120 76 80 80 80 80 120 80
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.83 2.10 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.83 2.10 2.17 2.83 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.83 2.17
0.00 2.83 4.93 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 29.43 31.53 33.70 36.53 38.70 40.87 43.70 45.80 47.97 50.13 52.30 54.47 57.30
2.83 4.93 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 29.43 31.53 33.70 36.53 38.70 40.87 43.70 45.80 47.97 50.13 52.30 54.47 57.30 59.47
192
D.E. Pitxeld, E.A. Jerrard / Journal of Air Transport Management 5 (1999) 185}192
Table 6 Departure simulations for the peak hour on 16R Random no.
A/C type
Deps gap (secs)
Time on runway
Gap#runway (mins)
Time from 0 (start)
Time from 0 (end event)
0.862456 0.876266 0.060652 0.657453 0.311012 0.687109 0.755674 0.693671 0.840188 0.733594 0.825936 0.944366 0.361341 0.600667 0.65873 0.516694 0.813899 0.322635 0.078211 0.787992 0.421401 0.723064 0.15187 0.171769 0.637507 0.150843
M M L M M M M M M M M M M M M M M M L M M M H H M H
80 120 76 80 80 80 80 80 80 80 80 80 80 80 80 80 80 120 76 80 80 80 75 120 80 75
50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
2.17 2.83 2.10 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.17 2.83 2.10 2.17 2.17 2.17 2.08 2.83 2.17 2.08
0.00 2.17 5.00 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 28.77 30.93 33.10 35.27 37.43 40.27 42.37 44.53 46.70 48.87 50.95 53.78 55.95
2.17 5.00 7.10 9.27 11.43 13.60 15.77 17.93 20.10 22.27 24.43 26.60 28.77 30.93 33.10 35.27 37.43 40.27 42.37 44.53 46.70 48.87 50.95 53.78 55.95 58.03
References
Table 7 Unconstrained runway capacity: scenarios 1}3 Scenarios
Arrivals 16R Arrivals 16L Arrivals 7}25 Departures 16R Departures 16L Departures 7}25 Totals Hourly air tra$c movement range
1
2
3
33 32 32 21 26 15
34 33 * 14 26 25
33 32 * 29 29 28
159 112}159
132 84}132
151 117}151
allow the identi"cation of crucial parameters, the variation in which may enable the postponement or abandonment of expensive airport infrastructure investment whilst still enabling increasing air transport demand to be safely met. Indeed, as a result of the work reported here the declared capacity at Rome Fiumucino International Airport will be increased to 84 movements per hour from the winter schedule, 1999 and the proposed fourth runway, planned for 2005 when movements reached 80 per hour, has been shelved.
ECAC/APATSI, 1995. Manual of Mature Air Tra$c Procedures. ECAC, Paris. Eurocontrol, 1997. European Database of Major Airports in the ECAC States. 1996 Annual Report, Brussels, Belgium. FAA, 1995. Airport Capacity and Delay. Advisory Circular 150/5060-5, US Department of Transportation, Washington. FAA, 1999. Land and Hold Short Operations (LAHSO). N7110.199, US Department of Transportation, Washington. IATA, 1999. Airport Ground Handling Manual, 19th Edition. Geneva, Switzerland/ Montreal, Canada. ICAO, 1996. Procedures for Air Navigation Services. Rules of the Air and Air Tra$c Services, 13th Edition Doc. 4444-RAC/50, ICAO, Paris. ICAO, 1998. RCM and Guidance Material on Simultaneous Intersecting Runway Operations. Proposal for amendments of the ICAO EUR Air Navigation Plan, Serial No.EUR/NAT 98/12-AOP-RCM & GM (Rev.2), ICAO, Paris. Pit"eld, D.E., Brooke, A.S., Jerrard, E.A., 1998. A Monte-Carlo simulation of potentially con#icting ground movements at a new international airport. Journal of Air Transport Management 4, 3}9. Taha, H.A., 1982. Operations Research. Collier Macmillan, New York.