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

Ilir Mehmedi

Ministry of Transport and Communications, Civil Aviation Administration

Dame Gruev 1, 1000 Skopje, Republic of Macedonia

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 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 1 / Code element 2
Code No. / Aeroplane reference field length / Code letter / Wing span / Outer main gear wheel span
1 / Less than 800 m / A / Up to but not
including 15 m / Up to but not
including 4.5 m
2 / 800 m up to but not
including 1200 m / B / 15 m up to but not including 24 m / 4.5 m up to but not including 6 m
3 / 1200 m up to but not including 1800 m / C / 24 m up to but not
including 36 m / 6 m up to but not
including 9 m
4 / 1800 m and over / D / 36 m up to but not including 52 m / 9 m up to but not
including 14 m
E / 52 m up to but not including 65 m / 9 m up to but not
including 14 m
F / 65 m up to but not including 80 m / 14 m up to but not including 16 m

Table 2: Taxiway minimum separation distances [1]

Code
letter / Distance between taxiway centreline and runway centreline (metres) / Taxiway centreline to taxiway centreline (metres) / Taxiway, other than aircraft stand taxilane, centreline to object (metres) / Aircraft stand taxilane centreline to object (metres)
Instrument runways / Non-instrument runways
Code Number / Code Number
1 / 2 / 3 / 4 / 1 / 2 / 3 / 4
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 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]

ICAO
Aerodrome
Reference
Code
Letter / Span Criteria / Aircraft / Distance Between Taxiway Centreline & Runway centreline Instrument Runway / Taxiway Centreline To Taxiway Centreline / Taxiway, Other Than Aircraft Stand Taxilane, Centreline To Object
Type / Length / Span / a / b / c
B / 15m up to but not including 24m / CRJ / 26,68 / 21,21 / 87,70 / 33,50 / 21,50
C / 24m up to but not including 36m / A319
A320-200
B737-800 / 33,84
37,57
39,50 / 34,10
34,10
34,30 / 168,00 / 44,00 / 26,00
D / 36m up to but not including 52m / A310-300
B757-200
B767-300 / 46,66
47,33
54,94 / 43,90
38,06
47,57 / 176,00 / 66,50 / 40,50
E / 52m up to but not including 65m / A340-600
B777-200
B747-200 / 75,30
63,73
70,67 / 63,45
60,95
64,94 / 182,50 / 80,00 / 47,50
F / 65m up to but not including 80m / A380 / 73,00 / 79,80 / 190,00 / 97,50 / 57,50

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

Figure 5: Ljubljana Airport

Figure 6: Maribor Airport

Figure 7: Ohrid Airport

Figure 8: Osijek Airport

Figure 9: Pula Airport

Figure 10: Rijeka Airport

Figure 11: Skopje Airport

Figure 12: Split Airport

Figure 13: Zagreb Airport

Figure 14: Zadar Airport

Table 4: Distances between runway and parallel taxiways

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

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.