a380 infrastruture reqs - alternates

8/3/2019 A380 Infrastruture Reqs - Alternates

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Airbus A380 operationsat alternate airports

AACGNovember-2004

Version 2

DRAFT

1. Introduction

Within the next 2 years the Airbus A380 will enter commercial service. This aircraft will have a largerwingspan and weight than the largest aircraft currently in scheduled use on world air routes. However, otherdimensions, for example fuselage length and gear dimensions are not as large as other aircraft already inservice, such as the A340-600 and B777-300.Many airports need to adapt their airside infrastructure. Upgrading runways, and taxiways, relocatingtaxiways and even relocating aircraft stands and buildings to provide sufficient wingtip clearance, are

examples of the works that several airports may need to carry out before the A380 enters service.For airports which will see the A380 frequently such changes to the infrastructure may be reasonable . Whenan airport operates close to its full capacity, efficiency of operations is a prime factor as well as safety.Examples of airports, where large scale infrastructure changes could be economical, include the largecontinental gateways, and those airports whose home-carriers have ordered the A380 aircraft: for example,London-LHR, Paris-CDG, Frankfurt, New York-JFK, Los Angeles, Singapore, Hong Kong, Sydney, Dubaietc.

Besides these large hub and main base airports, there are other airports around the world that willexperience A380 operations. The operating frequency could be either on regular basis, such as one or twoscheduled arrivals a day, but also may be a much lower frequency such as for a flight diversion. Suchdiversions could be either due to the unavailability of the destination airport (because of weather oroperational issues) or because of an in-flight emergency. It is in the interest of in-flight safety to have areasonable number of alternate airports and runways available in addition to the scheduled ones.For those alternate airports, large scale changes to their existing airside infrastructure would be financially

excessive and never be economical. On the other hand, especially in the case of a filed alternate, aminimum should be done to properly handle the aircraft and its passengers.

The occurrences of flight diversions are relatively low and many alternate airports will see only a fewdiversions a year or, in the case of emergency alternates, may never see one. It may therefore bereasonable and admissible to maintain the level of operational safety by use of alternative measures,operational procedures and operating restrictions. The two cases of alternates (flight diversion or emergencyalternate) require different consideration. Those nominated regularly for use as a destination or takeoffalternate must meet a defined standard, which many states require to be similar to that of the scheduleddestination. Those used very infrequently, such as for an unexpected in flight diversion could alternativelyachieve an acceptable level of safety by establishing significant operational restrictions to cater for the lackof airport infrastructure, instead of fully complying with the ICAO Annex 14 Airport requirements to cater forcode F aircraft (as defined by ICAO in Annex 14 for an aircraft of the A380 geometric size) or even AACG

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A380 specifications.This is not substantially different than what is regularly done at airports who receive the occasional visit of anairplane bigger than their design aircraft: An 124, or even B 747 in many old airports.

1The A380 Airport Compatibility Group is an informal group, consisting of a number of European Aviation Authorities,

Airport and Industry representatives. It was formed to agree and promote a common position among the groupmembers on the application of ICAO requirements, with respect to the A380 aircraft, for infrastructure and operations atexisting major European airports that currently do not meet the requirements.


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This document aims to provide guidance for operators and States on the use of alternate measures,operational procedures or operating restrictions, in combination with the minimum level of infrastructurerequirements at possible alternate and even lower frequency use airports. States and airport operators areencouraged to review the guidance in this document, but as with the AACG Common Agreement Document(destination airports), it must be clearly understood that the final safety based decision at a particular airportremains the responsibility of the State and the airport operator.

The proposed procedures are based on the current state of knowledge, as used for the December 2002AACG recommendations. Several Aeronautical studies are on-going at this time and they could result inlower requirements than those proposed by the AACG (most noticeably for points which the AACG had leftopen in December 2002, such as OFZs, holding point position and runway to taxiway separation). Use ofpossible outcomes from the uncompleted studies would be premature.However it is possible that the outcome of some of these studies, expected within the next year, couldrender several proposed operational procedures unnecessary.

2. Infrastructure requirements

The airside infrastructure requirements for aircraft with a wingspan up to 80 meters (Code F) are given byICAO in Annex 14, Volume 1. These requirements are a sound basis for new airport design or future airportexpansion but in most cases impractical for determining changes to existing infrastructure.

While ICAO member states are encouraged to fully implement the new code F requirements for thedevelopment of their airports, it has also become clear that many states will have difficulties in complyingwith these specifications for the upgrade of their currently existing facilities. For this reason ICAO developeda circular for New Larger Aeroplane Operations at Existing Aerodromes. This circular identifies all issueswhich are of relevance to the operations of NLAs and proposes possible mitigation measures foraccommodation of NLAs at those airports that are unable to comply with annex 14, code F provisions. Thecircular does not specify what is acceptable and what is not: the responsibility remains with the localauthority. The State should decide on the suitability of lower requirements than those given by Annex 14,based on aeronautical studies. The principle is that safety requirements must be met, however efficiency ofoperations should also be considered, especially for airports which have a very low number of A380movements and therefore whose infrastructure is unlikely to be code F (or AACG)-compliant.

The ICAO circular for New Larger Aeroplane Operations at Existing Aerodromes also gives guidance onhow to conduct aeronautical studies

2. Several European Aviation authorities have, in close co-operation with

their airport organizations and industry, initiated a working group (A380 Airport Compatibility Group, AACG)which performed several studies resulting in a number of recommendations for handling the A380 at existingairports. The Common Agreement Document (version 2.1, December 2002) of this working group containsall these recommendations.Together with ICAO Annex 14 the AACG recommendations form a basis for the infrastructure requirementsat existing airports.

For many airports, especially those airports that in the near future will only see the A380 in case of diversion,even the AACG requirements may be hard to comply with. Deviations from these requirements are onlysanctioned when aeronautical studies are performed. Even conducting aeronautical studies at these airportscan be an excessive burden in the context of the low number of A380 movements. A better solution in mostcases is to implement operational procedures to overcome the non compliances. In chapter 3 of thisdocument, such possible operational procedures are given. The basic assumption for these proceduresis that the airport complies with the ICAO code E requirements.

Reference documents: ICAO, Annex 14,

Volume I, Aerodrome design and operations, fourth edition, July 2004.

ICAO, Circular on New Larger Aeroplane Operations at Existing Aerodromes,Cir 305 AN/177, June 2004

Common Agreement Document of the A380 Airport Compatibility Group,Version 2.1, December 2002

2Additional material of relevance for the production of an aeronautical study is available on the ECAC website

(http://www.ecac-ceac.org/nla-forum/index.php), where several states and authorities have decided to make theiraeronautical studies available as a reference.


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3. Alternative measures, operational procedures and operatingrestrictions

In assessing the suitability of a given airport as an A380 alternate, two situations can be distinguished:

The case of a planned alternate, where the airport is regularly declared in the flight plans of an airline asthe alternate in the case of unavailability (most of the time for weather conditions) of the destinationairport. In this case, the conditions of accommodation can and should be negotiated in advance bythe airport with the airline and the ATC services. There may be some restrictions to normal operations,but they should not be disruptive if only because, in the case of bad weather, the A380 is unlikely tobe the only diverted aircraft and the alternate airport also has to handle its own traffic.

The case of an unplanned diversion airport, most likely to be used for an aircraft emergency. In such a(rare) case, temporary disruption of operations at the alternate airport is to some extent tolerable.

The level of the operating restrictions that can be tolerated will be higher in the second case.

3.1 Runways

Runway widthAnnex 14 prescribes a runway width of 60m for Code F aircraft. Many long-range traffic airports however,and certainly those that will be filed as an alternate, have runways which are expected to comply with ICAOCode E requirements, i.e. a width of 45m.Subject to the A380 being certified on 45m wide runways, the AACG recommendations state that a 45 meterwide runway can be used for Airbus A380 operations.

No specific alternative measures, operational procedures and operating restrictions are proposedfor operations of an A380 on a 45 meters wide runway.

Runway strengthThe runway need only support the reduced operating weight at an alternate (airlines have quoted maximumMLW and two hours fuel) and the infrequent use would allow pavement concession action for theappropriate bearing strength.

Runway shouldersFor destination airports, AACG recommendations state that a 45 meter wide runway with 7.5 metershoulders on both sides can be used for Airbus A380 operations if the runway is also provided withadditional outer shoulders. These outer shoulders should be prepared for jet blast protection, engineingestion protection, and for supporting ground vehicles and their width should be at least 2x7.5m.The use of 2* 7.5 meter shoulders in Code E alternate airports instead of 2*15 meter wide shoulders(including the AACG outer shoulders) could therefore be an issue.

For an alternate airport, upgrading the total runway + shoulder width to 75m is mostly not viable. To findwhether, and under what conditions, the A380 can be operated on code E runways and shoulders, the focusshould be put on the intended use of the outer shoulder.

1. Jet blast and engine ingestion protection.The outboard engine of the A380 is located inside the shoulder of a code E runway (see picture below), so

there is still some protection (4.3m margin) against any blast, erosion and A380 outer engine ingestion thatcould be generated by its thrust.

On landing, blast, erosion and A380 engine ingestion protection is not critical for the A380 on such arunway, as the outboard engines are not fitted with thrust reversers.

Take-offs however may require the blast and erosion protection capabilities of the outer shoulders, beyondthe 4.3m margin offered by the inner shoulder. Absence of the outer shoulder could result in an ingestionrisk for the A380 on takeoff, or FOD on the runway or inner shoulders which could be hazardous for thefollowing movement.


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Use of a runway at a landing alternate is likely to happen on short notice. Specific preparation of the runwayand runway shoulders is not necessarily possible within the available time frame. However the landing doesnot present a specific risk and therefore special procedures are not necessary (although runway inspectionis advisable).In the take-off case more time is available and the departure of an A380 can be coordinated with other trafficand the need to inspect the runway,(if a 75m wide runway area is not already inspected on a regular basis).

Runway inspection must be carried out immediately after take off to check that no loose objects have beenblown onto the runway. In addition, a de-rated thrust may be used for takeoff at alternate airports, furtherreducing the engine hazard. It should be noted that the ingestion risk occurs in the very early part of thetakeoff roll, below about 35 knots. A special procedure would be required for A380 operations on 45mrunway without inner shoulders

2. Supporting ground vehiclesThe other function of the outer shoulder is to allow the passage of ground, mainly emergency, vehicles. Thewingspan of a Boeing B747-400 already exceeds the runway and shoulder width of a code E runway. Forcode E runways, the emergency vehicles already must be capable to make use of the strip part outside therunway shoulder.

Rescue and Fire Fighting vehicles are designed for operating over short distances on the natural soil of therunway strip. The lack of 7.5 meters of outer shoulder does therefore make no difference between code Eand A380 operations.

3. Bearing strengthThe inner shoulder must be capable of withstanding the occasional passage of the aircraft without incurringstructural damage to the aircraft. A380 alternate airport operations would result in a pavement loading belowor comparable to the most critical code E aircraft at Maximum Take-Off Weight (B777-300ER). If theshoulder is for example designed for the critical B777-300ER at MTOW, it should cater for an A380 atalternate airport weights.


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Future A380 operators have indicated that a take-off weight limitation, based on MLW + 2 hours fuel, isacceptable.

The suitability of the runway and shoulder pavement for an A380 take-off is therefore a matter of comparingit with the critical aircraft used for the design of the airport pavement.The outer shoulder does not have to be designed for the occasional passage of an aircraft. Some states /airports are studying the possibility of having the outer shoulder functions performed either by a stabilized

surface (which is a possibility also mentioned by the ICAO NLA circular) or even by a well tended grasssurface.As stated in the AACG Common Agreement Document, the decision on the bearing suitability of theshoulder (composition and thickness) is the responsibility of the airport or national authority. The authority isable to declare a limiting takeoff weight for the A380, based on the gear layout, in the AIP or pavementconcession documentation

Proposed alternative measures, operational procedures and operating restrictions for airports thatcannot comply with ICAO requirements or AACG recommendations related to shoulder width (incombination with at least 45 meter wide runway).

Runway and shoulder FOD inspection must take place before each A380 take-off if a 75 meters widerunway area is not inspected on regular basis.

Runway and shoulder FOD inspection must take place after each A380 take-off.

Restrictions on actual take-off weight if the airport pavement PCN is not sufficient to handle an A380 atMTOW; airlines will judge whether the published PCNs are appropriate for their outbound flights. MLW

plus two hours fuel would appear to be a good measure for the majority of cases

[Comment: When possible it is advised to have runway and shoulder FOD inspection before and after each A380landing]

4. Runway edge lightsRunway edge lights are provided along both sides of the runway. They are located on the edge of therunway or a maximum of three meters to the outside of the edge. In most cases elevated (and frangible)constructions are used that could be subject to engine blast as the edge lights are almost in line with theouter engines of the A380.Tests have been carried out to see if light fittings, currently available on the market, can withstand blastprofiles comparable with an A380 engine. The results of these tests will soon become available

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Alternatively, the airport or local authority can perform runway edge light inspection after each A380departure (which may well by required for FOD reasons). As the outer engines of an A380 are not fitted withthrust reverse systems, it is not required to perform a runway edge light inspection after the landing of anA380.

Proposed alternative measures, operational procedures and operating restrictions for airports withnon blast resistant elevated runway edge lights on a 45 meters wide runway.

Runway edge lights inspection after each A380 departure.

3.2 Taxiways

Taxiway widthThe ICAO Annex 14 Code F taxiway width is 25m, or 2m more than Code E. The A380 has a wheel track0.3m larger than the Code E limit.Extensive deviation studies, carried out at several airports around the world, have shown that the deviationof large aircraft (code E) is much less than the 4.5 meters margin used in the formula to determine thetaxiway width. Results show that a deviation of less than 2.5 meters is a very realistic value under thecondition that proper guidance such as centre line lights and markings or equivalent guidance is provided fornight or low visibility operations.Additional to the above, it can be stated that the outer main gear wheel span of the A380 is such that theactual wheel to edge clearance (4.3m) is more than the 2.5 meters if the aircraft is taxiing on a code Etaxiway.

3Studies are in progress to assess the adequacy of current runway edge light fittings. The ECAC NLA website is

intended to reference those studies when available


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It can be concluded that on a 23 meter code E taxiway the A380 can taxi safely under the condition that thistaxiway is provided with proper guidance. Under these conditions no specific operational procedures isrequired.If the taxiways are not provided with proper guidance or if the airport / local authority does no feelcomfortable with the use of 23 meter wide taxiways, the use of follow me guidance can be a solution.

No specific alternative measures, operational procedures and operating restrictions are proposedfor operations of an A380 on a 23 meters wide straight taxiway.

Width of curved taxiwayTo facilitate the movement of an A380 on curved taxiways and on junctions / intersections of taxiways withrunways, aprons and other taxiways, fillets should be provided. The design of the fillet should ensure that aminimum wheel to edge clearance is maintained, based on Cockpit over Centre Line (COCL) steeringtechnique. ICAO requires a minimum wheel to edge clearance of 4.5 meters for curved taxiway segmentsAlso the AACG recommendations mentions a 4.5 meters wheel to edge clearance for curved taxiways,however in some states the use of smaller wheel to edge clearances (i.e. 2.5 meters) for the design oftaxiway fillets is under certain conditions accepted.

If the required wheel to edge clearance can not be guaranteed when using COCL steering technique, judgemental over steering is required. The use of judgemental over steering must be published in theappropriate aeronautical publications. If even judgemental over steering is not sufficient or if the airport /

local authority does not feel comfortable with this, additional markings (for over steering guidance) could bea practical solution

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to width of curvedtaxiway.

Reduced wheel to edge clearance

Use of judgemental over steering

Additional markings for over steering guidance.

Publication in the appropriate aeronautical documentation is required.

Taxiway shoulder widthBoth ICAO Annex 14 and the AACG Common Agreement Document recommend a 60 meters wide strip tobe protected against shoulder erosion and engine ingestion risk. The shoulders could build up of a paved, a

stabilized or a natural surface (experienced at CDG for many years). The A380 engine ground clearance is afactor. The inner engines are 0.5m higher and the outer engines 1.2m higher than the 747-400 ones, whichwould decrease the ingestion and jet blast risks. If the airport / local authorities does not feel comfortablewith the shoulder surface in combination with A380 operations, the possibility remains to taxi with bothoutboard engines idle or even shut-off. The feasibility of this must first be confirmed by the manufacturer.

Taxiing on two engines is not unusual but is mainly a practice after landing. Taxiing on two engines beforetake-off requires the outboard engines to be started up near or even at the runway which can result in a longblockage of the runway and consequently disturbing other traffic flow.If it is required that the outer engines being shut of, special attention should be given to tight curves wherenormally asymmetric power is used to move the aircraft through the curve.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to shoulder width.

Taxing with outboard engines on idle thrust.

In the extreme case the airport authority could require taxiing with outboard engines shut-off (feasibilityto be confirmed by manufacturer) or the aircraft could be towed.



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3.3 Runway - taxiway separations

Separation between runway and parallel taxiway is given by ICAO as 115 meters for a non instrumentrunway and 190 meters for an instrument runway. Both are applicable to code F. For code E theseseparation distances are 107.5 and 182.5 meters.

Although AACG agreed with the 115 meters some members have the opinion that the 115 meters for non-

instrument runways is at the very lower boundary of what could be acceptable. On the other hand AACGalso have the opinion that the 190 meters for instrument runways may be conservative

4.

Within the frame of ICAO rules, if the runway-taxiway separation at an alternate airport with few (if any)foreseeable A380 movements does not comply with code F SARPs, restrictions on the simultaneous use ofthe runway and taxiway can be considered.

For this several cases can be distinguished, based on code E separation distances:

a) Landing of an A380 on an non instrument runway, Runway taxiway separation is 107.5 meters,The runway taxiway separation is based on a half runway-strip width of 75 meters plus half thewingspan of the aircraft on the parallel taxiway. The half runway strip width of 75 meters is equal forboth ICAO code E and code F. Landing (under VFR) of an A380 in this case may not restrict theuse of the parallel taxiway for aircraft with a wingspan of less than 65 meters. No specificprocedures are required.

b) Landing of an A380 on an instrument runway, Runway taxiway separation is 182.5 meters,The runway taxiway separation is based on a half runway strip width of 150 meters plus half thewingspan of the aircraft on the parallel taxiway. The half runway strip width of 150 meters is equalfor both ICAO code E and code F. Landing of an A380 in this case will not restrict the use of theparallel taxiway for aircraft with a wingspan of less than 65 meters. No specific procedures arerequired

c) Take-off of an A380, runway taxiway separation is 107.5 meters,For the take-off case the half runway strip width equals 75 meters plus half the wingspan of theaircraft on the parallel taxiway. The half runway strip width of 75 meters is equal for both ICAOcode E and code F. Take-off of an A380 may not restrict the use of the parallel taxiway for aircraftwith a wingspan of less than 65 meters. No specific procedures are required

d) Take-off of an A380, runway taxiway separation is 182.5 meters,For the take-off case the half runway strip is 75 meters plus half the wingspan of the aircraft on theparallel taxiway. The half runway strip half-width of 75 meters is equal for both ICAO code E andcode F. Take-off of an A380 will not restrict the use of the parallel taxiway even not for A380aircraft. No specific procedures are required.

e) Taxiing of an A380 on a parallel taxiway, runway taxiway separation is 107.5 meters,The A380 wingtip will infringe the runway strip with a distance of 7.5 meters. Operations on therunway should therefore temporarily be halted until the A380 has left the parallel taxiway.

f) Taxiing of an A380 on a parallel taxiway, runway taxiway separation is 182.5 meters,The A380 wingtip will infringe the runway strip with a distance of 7.5 meters

5. Take-off operations

can be operated as normal but instrument landings may temporarily be halted until the A380 hasleft the parallel taxiway. Non instrument landings however could be operated normally

From the above it can be concluded that the critical point is not the operation of an A380 on the runway, butrather the operation of an A380 on the parallel taxiway.

4 The FAA specifies a 600ft (182 m) separation in the US for FAA ADG VI category (equivalent to ICAO Code F). Otherstates are studying the issue of allowing lower separations than those of ICAO, code F. The ECAC NLA website isintended to reference those studies when available.

5For an A380 taxiing on a code E parallel taxiway, the distance from runway centerline to the A380 wingtip is 142.5m.

With respect to FAA requirements, for a 747-400 taxiing on a Group V parallel taxiway, the distance from runwaycenterline to the 747 wingtip is only 122m.


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Recommended alternative measures, operational procedures and operating restrictions for airportsthat can not comply with ICAO requirements or AACG recommendations related to runway taxiwayseparation.

When an A380 uses the parallel taxiway next to a runway, operations on that runway should berestricted or even halted if the runway taxiway separation is less than 115 meters (under visualconditions).

[Comment: in annex 14, the width of the runway strip is a permanent characteristic attached to the runway, not to thetype of operations and the aircraft size. It may be necessary to note that proposals b, d, and f consist in saying that aninstrument runway in visual conditions can be operated with the clearances of a non-instrument runway, with anacceptable level of safety. In practice, this may need to be validated by ATC services]

3.4 Obstacle Free Zone

The Obstacle Free Zone protects the airspace above the inner approach surface, the inner transitionalsurfaces, the balked landing surface and that portion of the strip bounded by these surfaces. The OFZ maynot be penetrated by any fixed obstacle other than a low-mass and frangible mounted one required.

The width of the lower surface of the OFZ is 120 meters for code E (and lower) aircraft. For code F aircraft

the width of the lower surface is specified by ICAO to be 155 meters. The justification used is that not onlythe wingspan is 20 meters larger (on initial code E 60 meters) but also the runway width is 15 meters larger(60 meters code E).

The ICAO OCP Balked Landing Study is expected to reduce this value6. It should be noted that France has

already made an Aeronautical Study showing that an inner approach surface width of 133m for A380operations will provide the same level of safety than for current B747-400 operations at existing Code Erunways.

3.5 Runway Holding Positions

Runway holding positions have two purposes, collision prevention and protection of the ILS signal.

a) For collision risks, the distance between runway holding point and runway centre line will bedetermined by the biggest aircraft that can use the runway as well as the geometry of the aircraft at theholding position.

b) The other purpose is to prevent unacceptable interference with the ILS signal. During ILS CAT II/IIIoperations, the runway holding positions needs to be positioned in such a way that the critical and thesensitive areas are free of any aircraft movement on the ground

For code E the minimum distance for the runway holding position is 90 meters, for code F this distance is107.5 meters. These distances are based on

an assumed aircraft with a tail specific height (code E; 20 meters, code F; 24 meters), a distance fromnose to the highest part of the tail (code E; 52.7 meters, code F; 62.2 meters) and a nose height (bothcode E and F ; 10 meters) holding at an angle of 45 or more with respect to the runway centre line,being clear of the obstacle free zone (OFZ) .

As can be concluded from above the Runway Holding Position is not only a function of the size of the

Holding aircraft, but also of the dimensions of the Obstacle Free Zone (OFZ)7

.

6 Final result is expected to be reached shortly by the international bodies studying the issue. The OCP 14 meeting inMarch 2005 should validate an Annex 14 amendment, including a reference to guidance contained in a balked landingcircular (to be finalized in February 2005).

7Studies are in progress to assess the adequacy of current holding points (90m) for normal A380 operations. The

ECAC NLA website is intended to reference those studies when available.


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As an interim solution, operational procedures can be implemented which prevent aircraft coming near therunway in case of the occasional A380 landing. If the airport is equipped with ILS CAT II/III holding positions,these could be used for this purpose. Similar restrictions are already published on airport charts.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related runway holdingpositions.

Holding aircraft further from the runway in case of an A380 landing may be required (i.e. the ILS CATII/III holding positions).

Holding aircraft at the parallel taxiway, away from the runway entry taxiway.

Establish the appropriate ATC procedure.

3.6 ILS Category II / III operations

Operations during low visibility conditions require special attention to avoid unacceptable interference withthe ILS glide path and localizer facilities. For ILS Cat II / III operations this could result in additional runwayholding positions. On most airports with Cat II / III capability additional runway holding positions are located150 meters from the runway centre line to prevent aircraft penetrating the ILS sensitive area during lowvisibility operations.

Unacceptable interference to the ILS signal, due to the presence of an A380, could result in largerdimensions of the ILS sensitive area.Studies and simulations

8are being performed to find out if an A380 on a parallel taxiway and at holding

positions gives more interference to the ILS signal than the current large aircraft. The size of the tail fin isunder special consideration.Preliminary results shows that the effect on the ILS signal is strongly related to local conditions and thereforea standard and uniform solution can not yet be provided. Also the acceptable level of disturbance is not thesame at all airports and in all states.

If an alternate airport expects to handle diverted A380 operations during low visibility conditions, specialattention should be given to this kind of operations. An operational plan must be set up to guarantee that theILS signal is not disturbed or alternatively that operations at the runway are temporarily restricted.

3.7 Taxiway minimum separation distances

To reduce wingtip collision risk to an acceptable level, minimum separation distances for taxiways andtaxilanes are implemented. For this, ICAO has specified separation distances for the different aircraftcategories and taxiway / taxilane situations. For code F, these minimum separation distances are based onextrapolation of the distances given for code E. However, risk assessment, as well as operationalexperience with code E aircraft, has shown that large aircraft can be operated safely on taxiways withsmaller separation distances than those given by ICAO.AACG recommendations for minimum separation distances are based on these risk assessment andoperational experiences. The results of the taxiway deviation studies carried out by London-LHR, Frankfurt,Amsterdam and Paris-CDG were used for these recommendations.

Different type of taxiway separation distances can be considered:

1. Parallel taxiways (Taxiway centre line to taxiway centre line)2. Taxiway centre line to object3. Aircraft stand taxilane to object

Parallel taxiways (Taxiway centre line to taxiway centre line)In ICAO Annex 14, the minimum distance between two parallel taxiways is given as 97.5 meters for code Faircraft. AACG recommend a distance of 91 meters if proper guidance, such as centre line lights orequivalent guidance, is provided for night or low visibility operations.

8Studies are in progress to assess the effect of A380 operations on the ILS signal. The ECAC NLA website is intended

to reference those studies when available


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Many alternate airports will have parallel taxiways which are designed for code E aircraft. A separationdistance of 80 meters will in those cases normally be available. This does not mean that the A380 cannotmake use of one of the two parallel taxiways. If an A380 operates on one of the taxiways, the other taxiwaywill be restricted for use by aircraft smaller than code E.

The ICAO requirement for parallel taxiways to be separated by 97.5m gives a margin of 17.5 meters whentwo A380 aircraft taxi on parallel taxiways. The AACG recommends 91 meter which results in a margin of

11m.The maximum wingspan for the other aircraft in the case that an A380 taxies on parallel taxiways separatedby only 80 meters can easily be calculated: taxiway separation minus half wingspan of A380 minus marginequals half wingspan of the aircraft on the other taxiway.

ICAO annex 14 requirements:80 meters 40 meters 17.5 meters = 22.5 meters or a maximum wingspan of 45 meters (i.e. aircraft likeA310, A300 and B757).

AACG requirements:80 meters 40 meters 11 meters = 29 meters or a maximum wingspan of 58 meters (i.e. aircraft like B767and MD11).

Special attention must be given to curved taxiways or turning manoeuvres on taxiways. At all times aminimum margin of 17.5 meters, or 11 meters if proper guidance is available, must be guaranteed. If this

minimum margin can not be provided or the local authority does not feel comfortable with the actual marginadditional procedural separation must be provided.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related parallel taxiways

Restrict aircraft operations on the taxiway not used by the A380, to aircraft with a maximum wingspan of45 meters.

If proper guidance is given, this restriction can be lifted to a maximum wingspan of 58 meters.

If necessary, procedural separation must be provided.


Establish appropriate ATC operational procedures.

Taxiway centre line to objectFor taxiway to object clearance, ICAO requires 57.5 meters while AACG recommend 49 meters if proper

guidance is available. However both accept lower separations distances for taxilanes based on the fact thattaxiing is more accurate on taxilanes. Although recent taxiway deviation studies have not found any relationbetween taxi speed and deviations from the taxiway centre line, it is still one of the reasons why ICAO allowssmaller clearances on taxilanes. Extra caution on the more congested apron area could also be a factor inbetter taxilane accuracy.

The local authority could allow taxilane to object clearances on taxiways, if necessary with measures suchas taxi speed reduction. If these measures can be ensured on the taxiway, e.g. by follow me guidanceand/or clear publication in the aeronautical documents, it may be acceptable to taxi an A380 on taxiwayswith less than the required clearances.If proper guidance, like for example taxiway centreline lights, is available, an A380 could be operated on acode E taxiway (47.5 meters separation distance to object).

Special attention must be given to curved taxiways or turning manoeuvres. At all times a minimum margin of10.5 meters, or 7.5 meters if proper guidance is available, must be guaranteed.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to taxiway objectclearance

Use of code E taxiways with warnings to exercise caution, and possibly reduction of taxi speed (taxiwayto object clearance = 47.5 meters)

Follow me guidance or marshalling can be used.

In an ultimate step, towing the aircraft can be an option (if taxiway to object clearance less than 47.5meters)



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Aircraft stand taxilane to objectFor aircraft stand taxilanes ICAO requires 50.5 meters clearance to any object while AACG recommend 47.5meters if proper guidance is provided. Further reduction of the separations distances is difficult and willresult in higher and probably unacceptable risk of wingtip collision.If separations of 50.5 (ICAO) or 47.5 meters (AACG) can not be guaranteed, the use of Follow meguidance or marshalling but also towing the aircraft are possible solutions.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to aircraft stand taxilane object clearance

Follow me guidance or marshalling can be used.

Towing the aircraft on the taxilane.


3.8 Aprons and aircraft stands

It is unlikely that an airport that does not meet Code F requirements will have an aircraft stand on which anAirbus A380 can be parked without difficulties. It can be expected that the maximum aircraft that can be

parked on the stand is a Boeing 747-400 or equivalent.

The length of an A380 is similar to that of a B747-400. The depth of an aircraft stand will in most case not bean issue. As the A380 semi span is 7.5m more than a B747-400 the entire 7.5 metre margin is used andsafety would be compromised, unless adjacent stands are downgraded to smaller aircraft size.

On aircraft stands along concourses, the above can sometimes be difficult as the stands can be equippedwith fixed installations like passenger bridges and light poles. It is sometimes easier to park the A380 on aremote apron or even the cargo apron as these aprons have fewer restrictions on aircraft size.

When parking an A380 on stands where it is not designed for, marshalling is recommended and towing theaircraft on to the stand is an option.

Nose-in parking requires suitable tow trucks and tow bars for push-back on departure. If an airport doesnot have capable equipment, the A380 should be parked on a remote (or cargo) stand in such a way that

taxi-in and taxi-out on own power is possible. Attention should be given to blast issues, especially during nonstandard taxi-out manoeuvre.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not provide aircraft stands for an A380 that complies with ICAO requirements or AACGrecommendations.

Temporary downgrading adjacent aircraft stands.

Towing the aircraft on to the stand.

Use of remote / cargo stands or roll-through parking positions for handling the A380.


[Comment: In the case of an airport regularly filed as an alternate, it may be advisable to have a few marked remoteA380-capable stands (possibly downgrading adjacent stands), accessible by A380s under their own power]


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3.9 Taxiway bridges

For taxiway bridges, the following aspects are relevant;

Bridge width,

Blast protection,

Accessibility for rescue and fire fighting vehicles and

Structural maximum load, also applicable to tunnels underneath taxiways (and runways)

Bridge widthFor the width of a taxiway bridge, AACG recommends a minimum of 49 meters (ICAO requirement 60meters minimum). Smaller bridges are acceptable if a proven method of lateral constraint is provided. If thetaxiway bridge is designed for code E aircraft, the width of the bridge will be 44 meters minimum. In thatcase, an A380 can only use that taxiway bridge if lateral constraint is provided. If not, the A380 may not usethat taxiway bridge, under its own power. Towing the aircraft over the bridge is a possibility. Connecting anddisconnecting time requires consideration. As the number of A380 movements is very low, the operationaldisturbance may be acceptable.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to taxiway bridge width.

Towing the A380 over the taxiway bridge

Publication in the appropriate aeronautical documents that the A380 may not taxi under own power over

the bridge is required.

Blast protectionIf the width of the taxiway bridge is such that the outboard engines overhang the bridge structure, blastprotection of areas below the bridge may be necessary. In case jet blast protection cant be provided over awidth of 60m, taxiing with the outboard engines on idle thrust or even shut-off is a possibility.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to blast protection ontaxiway bridges.

Taxing with outboard engines on idle thrust.

In the extreme case the airport authority could require taxiing with outboard engines shut-off (feasibilityto be confirmed by manufacturer).


Rescue and fire fighting vehiclesAccess should be provided to allow rescue and fire fighting vehicles to intervene in both directions. This ishowever not a specific A380 issue. The wingspan of code E aircraft also exceeds the width of a code Etaxiway bridge.If the width of the bridge is not enough to provide vehicle passage on the bridge, when occupied by an A380or any other large aircraft, an alternative path for RFF vehicles must be provided. This path could be aservice road with separate service road bridge. On large airports, more than one RFF station is mostlyprovided. In most cases, a solution could be to intervene from both sides of the taxiway bridge if the RFFstations are not located on the same side of the bridge. Specified response times should be taken intoaccount.If an alternative path for RFF vehicles or response times from one of the RFF stations can not beguaranteed the solution could be to strategically position RFF vehicles on both sides of the taxiway bridgefor an A380 passage. As the A380 passage is only occasional, the disturbance of this procedure should beacceptable.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related to accessibility ofrescue and fire fighting vehicles.

Strategically position RFF vehicles on both side of the taxiway bridge.

Structural maximum loadThe maximum load of the bridge or tunnel is a prime factor in determining the capability for A380 aircraft.Taxiway bridges and tunnels designed to be capable of supporting a B747-400 at MTOW, are in any casecapable of supporting a A380 on arrival. The Maximum Landing Weight (MLW) is less than the MTOW of a


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B747-400. The bridge should also be capable to support an A380 on departure as the airlines have quotedthat the actual take-off weight in practice will be limited to maximum MLW + 2 hours fuel (comparable to aB747-400 at MTOW). In that case no special procedures are required.

The actual take-off weight should be based on the bearing strength of the bridge / tunnel9, using concession

procedures if appropriate. For the alternate airport, it is necessary that the actual bearing strength of taxiwaybridges and tunnels be published in the appropriate aeronautical publications.

Proposed alternative measures, operational procedures and operating restrictions for airports thatcan not comply with ICAO requirements or AACG recommendations related bearing strength oftaxiway bridges or tunnels.

Publish the weight limitations on A380 taxi routes

3.10 Taxi routing

Specific taxi routes and procedures for diverted A380 aircraft may be necessary to permit A380 operationswith the existing airport infrastructure. This may for example involve extra runway occupancy and theprovision of turn pads. To specify a taxi route between the runway and the aircraft stand, all the itemsmentioned in the previous paragraphs should be addressed.

As the A380 movement is occasional, the operational disturbance could well be acceptable in relation to theenormous investment for upgrading the infrastructure. As these investments cost will be reflected into theoperational charges of the airport, the other airlines will probably accept the occasional disturbance adiversion will cause.

To specify a taxi route between the runway and the aircraft stand, all the items mentioned in the previousparagraphs should be addressed.

TaxiwaysIf an A380 can not operate on the taxiway parallel to the runway, taxiing on the runway becomes necessary.Turning pads at the end of the runway must then be available.Back tracking on the runway after landing or before take-off is not uncommon and normal practice on manyairports around the world. It is uncommon on airports where parallel taxiways next to runways are providedand where normally traffic volume is high. Back tracking on the runway could in that case not only causeoperational disturbance (runway is blocked for a longer time), but could also be source of additional runway

incursion risk. Caution should be made for alternate airports where in practice only the occasional A380movement needs taxing on (part of) the runway.

Taxiway bridgesThe taxi route between an aircraft stand and the runway can contain taxiway bridges or tunnels. Asmentioned in paragraph 3.7, taxiway bridges can be critical not only in width but certainly also in bearingstrength. If that is the case, it is wise to define taxi routings that bypasses the taxiway bridge or tunnel.Sometimes this will not be possible as the only route between runway and terminal area will be over thetaxiway bridge / tunnel. In that case, it is advisable to look for a parking position somewhere between therunway and the Taxiway Bridge / tunnel. In the extreme situation this could be part of the taxiway system oreven a non used runway.

Fortunately, flight diversions are rare. Therefore, the pilot is likely to be less familiar with the airport, its lay-out and special procedures. Disorientation is more likely to occur. To prevent mishaps during taxiing,especially when specific taxi routing have to be followed, guidance by follow me may be advisable,

especially in cases other than diversion to a planned alternate.

The design of taxi routes needs to be defined and validated in advance. Co-ordination with the ATC servicesand the airlines who intend to regularly file the airport as an alternate is a requirement. The taxi routing,together with all the other special procedures for the A380, must be published in the appropriateaeronautical documentation.

9If the bridge load is severely limited, the airlines involved would have to plan for means of limiting the take-off payload.


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3.11 Other items

Besides the mentioned infrastructure items, iother ssues related to A380 operations at an alternate airportrequire resolution.The following items are a relevant but not exhaustive list.

a) Rescue and Fire Fighting services

The need to upgrade the RFF equipment should be assessed with regard to the national and internationalregulations. ICAO, FAA as well as JAA have requirements on RFF services on alternate airports. It is theresponsibility of the local authority to determine acceptability of the available RFF services and equipment.

b) Snow removalThe blast issues raised in the runway paragraph are also valid for snow removal. It is therefore necessarythat airports, which can be filled as an alternate, prepare a plan for runway snow removal based on thecharacteristics of the A380.

c) Ground servicingNormally, ground servicing can be achieved with GSE commonly used by other wide body jets (main deckservice). Attention must be given for ground service equipment which can be specific for A380 operations.This could be:

a capable tow truck and suitable tow bar at alternate airports where towing the aircraft is unavoidable

Suitable de-icing equipment

In the case of a filed alternate, the servicing of the aircraft, its passengers, cargo and baggage should beprepared in advance; the airline should ensure the availability of the relevant handling equipment.

Suggest adding charts on A380 servicing and door locations (very similar to 747)


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4. Conclusion

For airports that will be an A380 alternate or even have a low number of A380 movements it is clear thatfinancially it will be difficult to fulfil the ICAO requirements and, in most cases, even the AACGrecommendations.

This document provides a number of alternative measures, operational procedures and operating

restrictionsthat can be implemented to cope with the occasional movement of the A380 aircraft without theburden of high investment cost and infrastructure changes.This is not substantially different than what is already common practice at many airports who accommodatethe occasional visit of an airplane bigger than their design aircraft: for example, an An-124, or even B 747 atmany existing airports.

Implementing the proposed procedures will have an impact on the airport /airside operations and thereforeshould be analysed carefully. Close cooperation between airport / local authority, ATC services and theairlines that could file the airport as an alternate is therefore a requirement. All necessary routings,operational minimums, restrictions, procedures and requirements for ground equipment should bedetermined, approved and published before the first A380 can be expected.

As the use of alternate airports is a rare occasion, it is also the responsibility of the airlines to train their crewand provide them with the appropriate documentation to safely operate the aircraft at the alternate airport.

References

ICAO, Annex 14,Volume I, Aerodrome design and operations, fourth edition, July 2004.

ICAO, Circular on New Larger Aeroplane Operations at Existing Aerodromes,

Cir 305 AN/177, June 2004 Common Agreement Document of the A380 Airport Compatibility Group,

Version 2.1, December 2002

Additional material of relevance with respect to the A380 operations is available on the ECAC website (http://www.ecac-ceac.org/nla-forum/index.php), where several states and authorities have decided to maketheir aeronautical studies available as a reference

Information on A380 Airport Characteristics for Airport Planning manual can be found on the AIRBUSwebsitehttp://www.content.airbusworld.com/SITES/Technical_Data/docs/AC/DATA_CONSULT/AC_A380.pdf
http://www.ecac-ceac.org/nla-forum/index.phphttp://www.ecac-ceac.org/nla-forum/index.phphttp://www.ecac-ceac.org/nla-forum/index.php

a380 infrastruture reqs - alternates

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