Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOUEVERING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

Stanislav Pavlin, Marko Rapan University of Zagreb Faculty of Transport and Traffic Engineering Vukelićeva 4, 10000 Zagreb, Croatia [email protected] , [email protected]

Ilir Mehmedi Ministry of Transport and Communications, Civil Aviation Administration Dame Gruev 1, 1000 Skopje, Republic of Macedonia [email protected]

ABSTRACT

International aviation organizations regulate distances between runway centreline and parallel taxiway centreline and apron taxiway centreline. International Civil Aviation Organization defines several types of taxiway and clearly specifies taxiways on apron. Comparing international regulations data with actual situation on airports in several countries in the region: Croatia, Macedonia and Slovenia showed that numbers of airports are not satisfying recommended practices.

1 INTRODUCTION

In the sixties of the last century, at times of intensive opening of the former Yugoslavia to tourism, the underdevelopment of the road infrastructure opened up the doors wide to air traffic. New airports were built in the vicinity of major urban centres and the existing military airports were upgraded for civil aviation.

The International Civil Aviation Organization – ICAO, beside recommendations for taxiways also defines the runway strip which surrounds the runway with the main purpose of reducing the risk of damaging the aircraft that may run off the strip i.e. of protecting the aircraft that flies above it during take-off or landing. The taxiway parallel to the runway has to be located in such a way that no part of the moving aircraft protrudes into the runway strip.

The International Air Transport Association – IATA recommends dual parallel taxiways to the runway.

The analysis included the airports for conventional aircraft of reference code 4E according to ICAO in Croatia, Macedonia and Slovenia.

1.1 Recommendations of International Civil Aviation Organization

The taxiways are defined areas on the ground as paths intended for the movement i.e. taxiing of aircraft. The main function of taxiways is to connect the runway with the apron. Regarding

1 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES traffic operations, it is recommended that the aircraft that had landed, during taxiing along the taxiways should not interference the aircraft approaching take-off. This means that after landing, the aircraft leaves the runway and taxiing along the taxiways i.e. several taxiways, arrives undisturbed to the apron for aircraft handling.

The shortest possible distance between the aircraft parking stands and the runway should be insured and the intersecting of taxiways and runways avoided. The recommendations should be met wherever possible and if this is allowed by the physical characteristics of the airport location itself.

ICAO defines several types of taxiways as exit-entrance, rapid exit, parallel, apron taxiways, aircraft stand taxilanes and their specific characteristics are clearly indicated.

Parallel taxiway is parallel to the runway. The exit-entrance taxiways connect the runway with parallel taxiway or with the apron. They may be at right angle or acute angle which are then called rapid exit taxiways since they allow higher speeds of aircraft when leaving the runway. The apron taxiway is mainly located at the peripheral part of the apron providing the taxiing route across the apron. The aircraft stand taxilane is the marked part of the apron intended only for the entrance to the aircraft stand.

The separation between the parallel centrelines of runway and parallel taxiways is determined by the separation criteria because of safe movement of aircraft on the manoeuvring area. The separation depends on the aeroplane reference field length (code number 1–4), the wing span and the outer main gear wheel span of the respective aircraft (code letter A–F), presented in Table 1. Table 1: Airport reference code [1] Code element 2 Code element 1 Cod Aeroplane reference field Code Outer main gear wheel e length letter Wing span span No. 1 Less than 800 m A Up to but not Up to but not including 15 m including 4.5 m 2 800 m up to but not B 15 m up to but not 4.5 m up to but not including 1200 m including 24 m including 6 m 3 1200 m up to but not C 24 m up to but not 6 m up to but not including 1800 m including 36 m including 9 m 4 1800 m and over D 36 m up to but not 9 m up to but not including 52 m including 14 m E 52 m up to but not 9 m up to but not including 65 m including 14 m F 65 m up to but not 14 m up to but not including 80 m including 16 m

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Table 2: Taxiway minimum separation distances [1] Distance between taxiway centreline and runway Taxiway Taxiway, Aircraft centreline (metres) centreline other stand Instrument runways Non-instrument runways to than taxilane taxiway aircraft centreline Code Number Code Number Code centreline stand to object lette (metres) taxilane, (metres) r centreline 1 2 3 4 1 2 3 4 to object (metres)

A 82,5 82,5 - - 37,5 47,5 - - 23,75 16,25 12 B 87 87 - - 42 52 - - 33,5 21,5 16,5 C - - 168 - - - 93 - 44 26 24,5 D - - 176 176 - - 101 101 66,5 40,5 36 E - - - 182,5 - - - 107,5 80 47,5 42,5 F - - - 190 - - - 115 97,5 57,5 50,5

It is recommended that the separation distances should not be less than the appropriate dimensions specified in Table 2.

In the Aerodrome Design Manual [2] the ICAO recommends the configuration of taxiways and apron taxiways in relation to the runway (Figure 1).

Figure 1: Configuration of the manoeuvring area and the apron [2]

1.2 Recommendations of the International Air Transport Association

The definitions of taxiways and recommendations of IATA are based on the ICAO definitions and recommendations. In the Airport Development Reference Manual [3] apart from the already mentioned minimum separation distances of the taxiway centrelines, IATA specifies also the type of aircraft according to the code letter, which the respective separation distance refers to (Table 3). In planning new runways, IATA recommends also planning of dual parallel taxiways if this is allowed by the physical characteristics of the airport site. The dual parallel taxiways should be constructed in phases, according to the demand requirements, and in planning a space for the second parallel taxiway should be reserved. The advantage of such a system of taxiways is the

3 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES two-way movement of aircraft simultaneously. The optimal planning of the manoeuvring area according to IATA is presented in Figure 2.

Figure 2: Recommended configuration in relation to the runway [3]

Table 3: Minimum separation distances according to the aircraft type [3] Distance Between Taxiway, Taxiway Taxiway Other ICAO Centreline Centreline Than Aerodrome Aircraft & Runway To Aircraft Reference Span Criteria centreline Taxiway Stand Code Instrument Centreline Taxilane, Letter Runway Centreline To Object Type Length Span a b c

B 15m up to but CRJ 26,68 21,21 87,70 33,50 21,50 not including 24m A319 33,84 34,10 C 24m up to but A320-200 37,57 34,10 168,00 44,00 26,00 not including B737-800 39,50 34,30 36m A310-300 46,66 43,90 D 36m up to but B757-200 47,33 38,06 176,00 66,50 40,50 not including B767-300 54,94 47,57 52m A340-600 75,30 63,45 E 52m up to but B777-200 63,73 60,95 182,50 80,00 47,50 not including B747-200 70,67 64,94 65m

F 65m up to but A380 73,00 79,80 190,00 97,50 57,50 not including 80m

4 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

2 AIRPORT LAYOUTS

For analysis the airports from three states in the region were selected: Dubrovnik, Ljubljana, Maribor, Ohrid, Osijek, Pula, Rijeka, Skopje, Split, Zadar and Zagreb (Figure 3).

Figure 3: Presentation of the selected airports

Here is the presentation of the layout of the Croatian, Macedonian, and Slovenian airports in the scale of approximately 1:25000 (Figures 4 – 14). Most of the layouts were obtained from Aeronautical Publication Information [4] [5] [6].

Figure 4: Dubrovnik Airport

5 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

Figure 5: Ljubljana Airport

Figure 6: Maribor Airport

Figure 7: Ohrid Airport

Figure 8: Osijek Airport

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Figure 9: Pula Airport

Figure 10: Rijeka Airport

Figure 11: Skopje Airport

Figure 12: Split Airport

7 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

Figure 13: Zagreb Airport

Figure 14: Zadar Airport

Table 4: Distances between runway and parallel taxiways

8 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

TAXIWAYS Exit-entrance Parallel Distance between Part of Taxiway length / taxiway apron AIRPORT Number Rapid Runway length centreline taxiways exit (metres) and system runway centreline (metres)

Dubrovnik 5 0 1700 / 3300 185,77 YES

Ljubljana 3 1 1980 / 3300 220 NO

Maribor 2 0 - - -

Ohrid 2 0 - - -

Osijek 2 0 - - -

Pula 4 0 2100 / 2950 250 NO

Rijeka 2 0 - - -

Skopje 6 0 2430 / 2450 210 YES

Split 2 0 - - -

Zadar* 1 0 - - -

Zagreb 5 0 2800 / 3252 200 YES *concerning to the civil runway

3 ANALYSIS OF AIRPORT MANOEUVRING AREAS

Comparing the recommendations of international aviation organizations, i.e. configuration of the manoeuvring area and apron with the actual situation of the previously presented airports, it may be noted that the majority of the airports fail to meet these recommendations. Out of eleven presented airports, five airports, Maribor, Ohrid, Osijek, Rijeka and Split do not have a parallel taxiway so that the exit-entrance taxiways connect the runway directly with the apron. In case of these five mentioned airports, great similarity in the configuration of the manoeuvring areas and apron may be seen. The reason lies probably in the same school, i.e. the same planners and designers who had almost a monopoly in the sixties in airport planning and design. Relatively few taxiways at some airports limit the capacity of the airsides. Concretely, the airports with two taxiways at a right angle or at an angle in relation to the runway, which connect the runway and the apron, have, if there are no other restrictions in the air, a capacity of about 10 operations per hour. At the edge of the apron, towards the runway, at all airports there is an apron taxiway which allows entrancing and exiting the stands. The exception is Split Airport, which features parking in two rows with the taxiway between these two rows and parallel to the runway.

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Zadar Airport can also be classified in the group which has no parallel taxiway (since the civil runway really does not have one), but because of two runways that are almost at the right angle to one another, the configuration of the manoeuvring area and the apron is somewhat different in relation to the previous group of airports. The apron is between the two runways and the taxiway that connects them to the apron is at the same time the apron taxiway, since the green island between the taxiway and the apron was turned into an apron in May of this year.

The remaining five airports have parallel taxiways. Out of these five, three airports, Dubrovnik, Skopje and Zagreb have a parallel taxiway as part of the apron taxiways system i.e. as extension of the taxiway at the peripheral part of the apron. In their documents ICAO and IATA clearly indicate the specific characteristics of the apron taxiways and parallel taxiways, so that the presentation of the mentioned airports leads us to the conclusion that they do not satisfy the recommendations.

Pula Airport features a physical layout of the manoeuvring area and apron that are partly in compliance with the ICAO recommendations, since the distance between the centrelines of the parallel taxiway and the apron taxiway is not in compliance with the recommended dimensions according to the airport reference code, i.e. the distance is ~60m, and it meets the requirements of aircraft up to the code letter C.

All the five mentioned airports that have taxiways parallel to the runway satisfy the code designation 4E (Table 2) regarding the inter-axis distance of the runway and the parallel taxiway.

Ljubljana Airport features distance of approximately 75m between the parallel taxiway and the edge of the service road at the peripheral part of the apron and satisfies the ICAO recommendations (Table 2). This is the only airport that features one rapid exit taxiway.

Out of eleven analyzed airports not one satisfies the IATA recommendations regarding the solution with dual parallel taxiways along the runway.

It is interesting that the majority of airports have not even been planned for a parallel taxiway so that usually there is an apron connected directly with the runway and most of the airports do not own the land for the construction of a taxiway parallel to the runway. The aviation bodies of that time had a function in the planning and designing as well as control during construction, and this is probably the reason, as well as because of the general saving in investments, that solutions had been found that probably already at those times, and today most certainly, do not meet the recommendations.

Table 5: Satisfying the recommended practice according to the international aviation organizations

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Number ICAO recomm. IATA recomm. Country of Yes No Yes No Airports Croatia 7 0% 100 % 0 % 100 % Macedonia 2 0 % 100 % 0 % 100 % Slovenia 2 50 % 50 % 0 % 100 % Croatia, Macedonia, Slovenia 11 9.09 % 90.91 % 0 % 100 %

4 CONCLUSION

It is obvious that the planners of the sixties did not consider the development of airports in the former state of Yugoslavia over a sufficiently long-term period. Whether this was due to the lack of funds to purchase land and secure space for the construction of the taxiway system that would satisfy the increasing operations i.e. regulations, remains unknown.

Information given by the main engineer of the construction of Dubrovnik Airport the data was obtained that the first decision made by the government was constructing a runway in the length of less than 2000m, probably for landing and take-off of propeller aircraft, and that the decision allowing construction of a runway sufficiently long to accommodate jet conventional aircraft was procured during the construction itself.

That was the time of modifications of power plants in civil aviation from the piston i.e. propeller into jet ones, which required approximately twice longer runways.

However, the later construction of completely new airports showed that the planners had not changed at all and had not “betrayed” their planning principles. Even Rijeka Airport – Krk (opened in 1970), and Osijek Airport – Klisa (1980) feature the same physical layout of the runway and the apron with two exit-entrance taxiways that connect the runway with the apron.

The consequences of such a development of airports in former Yugoslavia can be seen today in the failure to meet the recommended practice, which will present an increasing problem with the arrival of bigger aircraft and with the growth in traffic on the one side, as well as the increasingly rigorous ICAO conditions on the other side, so that these drawbacks will have to be eliminated in the long-term plans.

11 Stanislav Pavlin, Marko Rapan, Ilir Mehmedi COMPLIANCE OF CROATIAN, MACEDONIAN AND SLOVENIAN AIRPORT MANOEUVRING AREAS WITH INTERNATIONAL RECOMMENDED PRACTICES

REFERENCES

[1] Aerodromes, Annex 14 to the Convention on International Civil Aviation, Volume I, Aerodrome Design and Operations, International Civil Aviation Organization, Fourth Edition, July 2004, Montreal, Canada

[2] Aerodrome Design Manual (Doc 9157) Part 2, Taxiways, Aprons and Holding Bays, Doc 9157, 1999, Montreal, Canada

[3] The Airport Development Reference Manual, International Air Transport Association, 2004, Geneva, Switzerland

[4] Aeronautical Information Publication, Croatia

[5] Aeronautical Information Publication, Macedonia

[6] Aeronautical Information Publication, Slovenia

Biography

Prof. dr. sc. Stanislav Pavlin

Born in Zagreb 1949. Graduated at Faculty of Traffic and Transport Engineering, University of Zagreb in 1973. Master of Science degree acquired in 1980. Doctor degree acquired in 1989. at Faculty of Traffic and Transport Engineering. Assistant professor in 1990., associate professor in 1998. and professor in 2001. 1973.-1981. Airport planner at Zagreb Airport, 1981-1991. Head of organization, development and investment department at Zagreb Airport, 1991.-1993. Deputy Minister for civil aviation of the Republic of Croatia. 1993.-1994. consultant for development at Zagreb Airport. 1994-present Faculty of Traffic and Transport Engineering, Head of Aerodrome department.

Marko Rapan

Born in 1983 in Zadar, Croatia. 2001: Graduated at Grammar School Franjo Petrić, Zadar, naturalistic-mathematical course 2002-present: Student at Faculty of Traffic and Transport Engineering, Zagreb, University of Zagreb, course of Air Traffic Engineering

Ilir Mehmedi

Born in 1970 in Kičevo, Republic of Macedonia. Graduated at Faculty of Traffic and Transport Engineering, Zagreb, University of Zagreb, 1993 – course of road traffic; 1995 – course air traffic engineering; 2003-present: Postgraduate studies at the Faculty of Traffic and Transport Engineering, Zagreb 1997 – 1998: Assistant Air Traffic Controller in the Air Traffic Control Division; 1998–2000: Civil Aviation Advisor in the International Affairs Department; 2000 – 2002: Director of Security Division; 2002 – present: General Director of the Civil Aviation Administration, Republic of Macedonia

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