Airbus A380 operations at alternate airports

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draft 1 Airbus A380 operations at alternate airports Document proposed by the French DGAC to be published on the ECAC NLA website (based on the document presented to the AACG November-2004- Version 2) Version 1 – June 2006 1. Introduction The Airbus A380 is scheduled to enter commercial service in the second half of 2006. This aircraft will have a larger wingspan and weight than the largest aircraft currently in scheduled use on world air routes. However, other dimensions, for example fuselage length and gear dimensions are not as large as other aircraft already in service, such as the A340-600 and B777-300. Many airports need to adapt their airside infrastructure. Upgrading runways, and taxiways, relocating taxiways 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. When an 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 large continental gateways, and those airports whose home-carriers have ordered the A380 aircraft: for example, London-LHR, Paris-CDG, Frankfurt-FRA, New York-JFK, Los Angeles-LAX, Singapore-SIN, Hong Kong- HKG, Sydney-SYD, Dubai-DXB etc. Besides these large hub and main base airports, there are other airports around the world that will experience A380 operations. The operating frequency could be either on regular basis, such as one or two scheduled arrivals a day, but also may be a much lower frequency such as for a flight diversion. Such diversions could be either due to the unavailability of the destination airport (because of weather or operational issues) or because of an in-flight emergency. It is in the interest of in-flight safety to have a reasonable number of alternate airports and runways available in addition to the scheduled ones. Aircraft operations regulations make a distinction between destination alternate aerodromes, other alternate aerodromes required to be adequate (e.g. in JAR-OPS 1) and in-flight diversion aerodromes. 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, a minimum 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 few diversions a year or, in the case of emergency alternates, may never see one. It may therefore be reasonable 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 emergency alternate) require different consideration. Those nominated regularly for use as an alternate must meet a defined standard, which many states require being similar to that of the scheduled destination. Those used very infrequently, such as for an unexpected in flight diversion could alternatively achieve an acceptable level of safety by establishing significant operational restrictions to cater for the lack of airport infrastructure, instead of fully complying with the ICAO Annex 14 Airport requirements to cater for code F aircraft (as defined by ICAO in Annex 14 for an aircraft of the A380 geometric size) or even AACG1 A380 specifications. 1 The 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 group members on the application of ICAO requirements, with respect to the A380 aircraft, for infrastructure and operations at existing major European airports that currently do not meet the requirements. draft 2 This is not substantially different than what is regularly done at airports that receive the occasional visit of an airplane bigger than their design aircraft: An 124, or even B 747 in many “old” airports. This document aims to provide guidance for operators and States on the use of “alternate measures, operational procedures or operating restrictions2”, in combination with the minimum level of infrastructure requirements at possible alternate and even lower frequency use airports. States and airport operators are encouraged 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 decisions at a particular airport remains the responsibility of the provider State and the airport operator. The proposed procedures are based on the current state of knowledge, as used for the December 2002 AACG recommendations. Several Aeronautical studies are on going at this time and they could result in lower requirements than those proposed by the AACG (most noticeably for points which the AACG had left open in December 2002, such as OFZs, holding point position and runway to taxiway separation). Use of possible 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, could render several proposed operational procedures unnecessary. 2. Infrastructure requirements The minimum infrastructure regulatory requirements to allow an aeroplane to land at a particular aerodrome is to provide a runway of sufficient length and width. By evidence a means to clear the runway is also necessary: either a suitable taxiway, or to allow for a half-turn on the runway or a turn pad. The airside infrastructure requirements for aircraft with a wingspan up to 80 meters (Code F) are given by ICAO in Annex 14, Volume 1. These requirements are a sound basis for new airport design or future airport expansion 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 the development of their airports, it has also become clear that many states will have difficulties in complying with these specifications for the upgrade of their currently existing facilities. For this reason ICAO developed a circular for New Larger Aeroplane Operations at Existing Aerodromes. This circular identifies all issues which are of relevance to the operations of NLAs and proposes possible mitigation measures for accommodation of NLAs at those airports that are unable to comply with annex 14, code F provisions. The circular does not specify what is acceptable and what is not: the responsibility remains with the local authority. 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 of operations should also be considered. Especially for airports, which have a very low number of A380 movements and therefore whose infrastructure is unlikely to be code F (or AACG)-compliant, efficiency could be a minor issue. The ICAO circular for New Larger Aeroplane Operations at Existing Aerodromes also gives guidance on how to conduct aeronautical studies3. 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 existing airports. The Common Agreement Document (version 2.1, December 2002) of this working group contains all these recommendations. Together with ICAO Annex 14 the AACG recommendations form a basis for the infrastructure requirements at existing airports. The ICAO Circular on OFZ for New Large Aeroplanes is now available and related comments are included in this amended version. 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 only sanctioned when aeronautical studies are performed. Even conducting aeronautical studies at these airports 2 As defined in ICAO Circular 305 3 Additional 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 their aeronautical studies available as a reference. draft 3 can be an excessive burden in the context of the low number of A380 movements. A better solution in most cases is to implement operational procedures to overcome the non-compliances. In chapter 3 of this document, such possible operational procedures are given. The basic assumption for these procedures is 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 3. Alternative measures, operational procedures and operating restrictions 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 as the alternate in the case of unavailability (most of the time for reduced capacity due to severe weather conditions) of the destination airport. In this case, the conditions of accommodation can – and should – be negotiated in advance by the 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 to be the only diverted aircraft and the alternate airport also has to handle its own traffic.  The case of an unplanned diversion, most likely due to an aircraft emergency or technical problem. 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. Therefore the aerodrome operator should properly assess the probabilities, in time and numbers, of being used as an alternate for the A380, when defining the relevant provisions in order to guarantee adequate safety and regularity of operations. 3.1 Runways Runway width Annex 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 ICAO Code 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 meter wide runway can be used for Airbus A380 operations. No specific alternative measures, operational procedures and operating restrictions are proposed for take-off and landing operations of an A380 on a 45 meters wide runway. Runway strength The runway only needs to support the reduced operating weight at an alternate. Airlines have quoted /indicated that in the departure case from an alternate airport the operating mass will be in the range of Maximum Zero Fuel Mass plus three hours fuel. Also the infrequent use of the runway by A380 aircraft would allow pavement concession action for the appropriate bearing strength. However, in order to cater for operations at a higher mass without reducing the pavement life, it is recommended, as far as practicable, to provide bearing strength for the full Maximum Take-Off Mass (MTOM). Runway shoulders draft 4 For destination airports, AACG recommendations state that a 45 meter wide runway with 7.5 meter shoulders on both sides can be used for Airbus A380 operations if the runway is also provided with additional “outer” shoulders. These outer shoulders should be prepared for jet blast protection, engine ingestion 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 as for an alternate airport, upgrading the total runway + shoulder width to 75m is mostly not viable. Therefore the surfaces adjacent to these shoulders should be regularly inspected and cleaned, and the runway and its shoulders systematically inspected and cleaned after an A380 operation (this recommendation stems from the A380 test operations, in particular at Paris-Le Bourget airport during the Paris air Show). Prior to the A380 entry into service, the Flight Test program leads the A380 to be operated at many airports that are not code F compliant (ex: Paris Le Bourget) or sometimes even not code E compliant (ex: Tarbes airport, south west of France). The outputs of those operations are relevant in helping provide guidance for operators and States on the use of the A380 on such runways. Compared to other large aircraft, the following observations can be made 1. Jet blast and engine ingestion protection. The experience from the A380 flight tests as end 2005 indicated - Landing . Engine ingestion, blast and erosion protection is not deemed critical for the A380, as the outboard engines are essentially at idle thrust, are located relatively high (ground clearance of 1.9m at Maximum Ramp Mass) and are not fitted with thrust reversers. . The landing does not present a specific risk and therefore special procedures are not necessary (although runway inspection is advisable) - Take off 1. Engine ingestion protection The critical phase is at brake release (combination of low speed and high thrust). However, the suction phenomenon is observed right below the engine. In the absence of “outer” shoulders, the remaining 4.3m lateral margin of a code E runway (see following picture) looks therefore wide enough to avoid a possible ingestion of stones at the outer edge of the shoulders. In case the pilot would not rely on the stability of the shoulders of a code E runway or in case the 45m wide runway would not be equipped with shoulders, A380 operations on such runways could still be possible using a specific take off operational procedure proposed by the manufacturer that would avoid the creation of the suction phenomenon (such as reduced thrust on the outboard engines during the first seconds of the take off, to be further investigated). 2. Blast and erosion aspects For runways and shoulders with a width of less than 75m, the type of soil (arid, grass with loose stones, grass without stones…) is a matter of importance. The absence of shoulders could result in FOD on the runway or on “inner” shoulders, which could be hazardous to the following aircraft movement. In the take off case, more time is available and the departure of an A380 can be coordinated with other traffic. Runway inspection and cleaning as necessary must be carried out immediately after the A380 take off to check that no loose objects have been blown onto the runway. draft 5 2. Supporting ground vehicles The other function of the outer shoulder is to allow the passage of ground, mainly emergency, vehicles. The wingspan of a Boeing B747-400 already exceeds the runway and shoulder width of a code E runway. For code E runways, the emergency vehicles already must be capable to make use of the strip part outside the runway shoulder. Rescue and Fire Fighting vehicles are designed for operating over short distances on the natural soil of the runway strip. The lack of 7.5 meters of “outer” shoulder does therefore make no difference between code E and A380 operations. 3. Bearing strength The inner shoulder must be capable of withstanding the occasional passage of the aircraft without incurring structural damage to the aircraft. A380 alternate airport operations would result in a pavement loading below or comparable to the most critical code E aircraft at Maximum Take-Off Mass (B777-300ER). If the shoulder is for example designed for the critical B777-300ER at MTOM, it should cater for an A380 at alternate airport weights. Future A380 operators have indicated that a take-off weight limitation, based on MZFM + 3 hours fuel, is acceptable for alternate airports. The suitability of the runway and shoulder pavement for an A380 take-off is therefore a matter of comparing it 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 grass surface. As stated in the AACG Common Agreement Document, the decision on the bearing suitability of the shoulder (composition and thickness) is the responsibility of the airport or national authority. The authority is able to declare a limiting takeoff weight for the A380, based on the gear layout, in the AIP or pavement concession documentation draft 6 Proposed alternative measures, operational procedures and operating restrictions for airports that cannot comply with ICAO requirements or AACG recommendations related to shoulder width (in combination with at least 45 meter wide runway).  Runway and shoulder FOD inspection to a total width of 75 meters must take place before each A380 take-off if a 75 meters wide runway area is not already inspected on regular basis.  Runway and shoulder FOD inspection to a total width of 75 meters 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 at MTOM; airlines will judge whether the published PCNs are appropriate for their outbound flights. MZFM plus three hours fuel would appear to be a good measure for the majority of cases Observations should be recorded in order to adapt this policy. 4. Runway edge lights Runway edge lights are provided along both sides of the runway. They are located on the edge of the runway 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 the outboard engines of the A380. Tests have been carried out to see if some elevated lights, currently available on the market, can withstand blast profiles comparable with an A380 engine. These tests have shown that these light fittings should resist the A380 blast. The airport or local authority can perform runway edge light and signs inspection after each A380 departure (which may well by required for FOD reasons). As the outer engines of an A380 are not fitted with thrust reverse systems, it is not required to perform a runway edge light inspection after the landing of an A380. Proposed operational procedures for airports with a 45 meters wide runway.  Runway and runway shoulder as well as edge lights and signs inspection after each A380 departure. 3.2 Taxiways Taxiway width The ICAO Annex 14 Code F taxiway width is 25m, or 2m more than Code E. The A380 has a wheel track 0.3m larger than the Code E limit. Extensive deviation studies, carried out at several airports around the world, have shown that the deviation of large aircraft (code E) is much less than the 4.5 meters margin used in the formula to determine the taxiway width. Results show that a deviation of less than 2.5 meters is a very realistic value under the condition that proper guidance such as centre line lights and markings or equivalent guidance is provided for night 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 the actual wheel to edge clearance (4.3m) is more than the 2.5 meters if the aircraft is taxiing on a code E taxiway. As found for destination airports, it can be concluded that on a 23 meter code E taxiway the A380 can taxi safely under the condition that this taxiway is provided with proper guidance. Under these conditions no specific operational procedures is required. If the taxiways are not provided with proper guidance or if the airport / local authority does not feel comfortable 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 proposed for operations of an A380 on a 23 meters wide straight taxiway. Use of “follow me” guidance can be a solution if proper guidance is not available or the airport / local authority does not feel comfortable with the use of 23 meters wide taxiways. Airport/local authority should maintain markings, lights and pavement surfaces (e.g. snow removal) to provide good quality taxi guidance. draft 7 Width of curved taxiway To facilitate the movement of an A380 on curved taxiways and on junctions / intersections of taxiways with runways, aprons and other taxiways, fillets should be provided. The design of the fillet should ensure that a minimum wheel to edge clearance is maintained, based on Cockpit over Centre Line (COCL) steering technique. ICAO requires a minimum wheel to edge clearance of 4.5 meters for curved taxiway segments Also 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 of taxiway fillets is under certain conditions accepted. If the required wheel to edge clearance cannot be guaranteed when using COCL steering technique, judgemental oversteering is required. The use of judgemental oversteering must be published in the appropriate aeronautical publications. If even judgemental oversteering is not sufficient or if the airport / local authority does not feel comfortable with this, additional markings (for over steering guidance) could be a practical solution Proposed alternative measures, operational procedures and operating restrictions for airports that cannot comply with ICAO requirements or AACG recommendations related to width of curved taxiway.  Reduced wheel to edge clearance  Use of judgemental oversteering  Additional markings for over steering guidance.  Publication in the appropriate aeronautical documentation is required. Taxiway shoulder width Both ICAO Annex 14 and the AACG Common Agreement Document recommend a 60 meters wide strip to be protected against shoulder erosion and engine ingestion risk. The shoulders could be build up of a paved, a stabilized or a natural surface (experienced at CDG for many years). The A380 engine ground clearance is a factor. The inner engines are 0.5m higher and the outer engines 1.2m higher than those of the 747-400, which would decrease the ingestion and jet blast risksTaxiing on two engines is not unusual but is mainly a practice after landing. Taxiing on two engines before take-off requires the outboard engines to be started up near or even at the runway, which can result in a long blockage of the runway and consequently disturbing other traffic flow. Depending on the shoulder width and quality and given the location of A380 inboard and outboard engines, a specific procedure could be used (preferential use of some of the engines) Proposed alternative measures, operational procedures and operating restrictions for airports that can-not comply with ICAO requirements or AACG recommendations related to shoulder width.  Depending on the shoulder width and quality and given the location of A380 inboard and outboard engines, a specific procedure could be used (preferential use of some of the engines)  Publication in the appropriate aeronautical documentation is required. 3.3 Runway - taxiway separations Separation between runway and parallel taxiway is given by ICAO as 115 meters for a non instrument runway and 190 meters for an instrument runway. Both are applicable to code F. For code E these separation distances are respectively 107.5 and 182.5 meters. Although AACG agreed with the 115 meters some members have the opinion that the 115 meters for noninstrument runways is at the very lower boundary of what could be acceptable. On the other hand AACG also have the opinion that the 190 meters for instrument runways may be conservative4. This subject is also on the agenda of the ICAO Aerodromes Panel. 4 Some states are studying the issue of allowing lower separations than those of ICAO, code F. The ECAC NLA website is intended to reference those studies when available. draft 8 The original FAA regulation specifies a 600ft (182m) separation in the US for FAA ADG VI category (equivalent to code F). The FAA has produced the draft Advisory Circular 150/5300-13 Change 10 incorporating the reduction of this value to 550ft (167m) for Cat II/III operations and 500ft (152m) for Cat I operations. 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 of the 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 a 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 the wingspan of the aircraft on the parallel taxiway. The half runway strip width of 75 meters is equal for both ICAO code E and code F. Landing (under VFR) of an A380 in this case may not restrict the use of the parallel taxiway for aircraft with a wingspan of less than 65 meters. No specific procedures 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 the wingspan of the aircraft on the parallel taxiway. The half runway strip width of 150 meters is equal for both ICAO code E and code F. Landing of an A380 in this case will not restrict the use of the parallel taxiway for aircraft with a wingspan of less than 65 meters. No specific procedures are required 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 the aircraft on the parallel taxiway. The half runway strip width of 75 meters is equal for both ICAO code E and code F. Take-off of an A380 may not restrict the use of the parallel taxiway for aircraft with 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 the parallel taxiway. The half runway strip half-width of 75 meters is equal for both ICAO code E and code F. Take-off of an A380 will not restrict the use of the parallel taxiway even for A380 aircraft. 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 the runway 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 meters5. Take-off operations can be operated as normal but instrument landings may temporarily be halted until the A380 has left 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, but rather the operation of an A380 on the parallel taxiway. Recommended alternative measures, operational procedures and operating restrictions for airports that can-not comply with ICAO requirements or AACG recommendations related to runway – taxiway separation.  When an A380 uses the parallel taxiway next to a runway, operations on that runway should be restricted or even halted if the runway – taxiway separation is less than 115 meters (under visual conditions). 5 For 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 runway centerline to the 747 wingtip is only 122m. draft 9 3.4 Obstacle Free Zone The Obstacle Free Zone protects the airspace above the inner approach surface, the inner transitional surfaces, the balked landing surface and that portion of the strip bounded by these surfaces. The OFZ may not be penetrated by any fixed obstacle other than one, which is of low mass and frangibly mounted.. 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 only the 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 Circular 301 “New Larger Aeroplanes – Infringement of the Obstacle Free Zone: Operational Measures and Aeronautical Study” has been released in December 2005. In Part I, Chapter 3, §3.2.2 and 3.2.3 “Implementation guidance at code letter E aerodromes”, it is found that both the total width of 120m and the slope of 3:1 for the balked landing surface were found to be adequate for code letter F aeroplanes fitted with a modern digital autopilot of flight director with track hold guidance. 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 be determined by the biggest aircraft that can use the runway as well as the geometry of the aircraft at the holding position. b) The other purpose is to prevent unacceptable interference with the ILS signal. During ILS CAT II/III operations, the runway holding positions needs to be positioned in such a way that the critical and the sensitive 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 is 107.5 meters. These distances are based on “an assumed aircraft with a specific tail height (code E; 20 meters, code F; 24 meters), a distance from nose to the highest part of the tail (code E; 52.7 meters, code F; 62.2 meters) and a nose height (both code E and F; 10 meters) holding at an angle of 45º 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) 6. As an interim solution, operational procedures can be implemented which prevent aircraft coming near the runway 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 that cannot comply with ICAO requirements or AACG recommendations related runway holding positions.  Holding aircraft further from the runway in case of an A380 landing may be required (i.e. the ILS CAT II/III holding positions).  Holding aircraft at the parallel taxiway, away from the runway entry taxiway.  Establish the appropriate ATC procedure. 6 Studies 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. draft 10 3.6 ILS Category II / III operations Operations during low visibility conditions require special attention to avoid unacceptable interference with the ILS glide path and localizer facilities. For ILS Cat II / III operations this could result in additional runway holding positions. On most airports with Cat II / III capability additional runway holding positions are located 150 meters from the runway centre line to prevent aircraft penetrating the ILS sensitive area during low visibility operations. Unacceptable interference to the ILS signal, due to the presence of an A380, could result in larger dimensions of the ILS sensitive area. Studies and simulations7 are 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 is under special consideration. Preliminary results shows that the effect on the ILS signal is strongly related to local conditions and therefore a standard and uniform solution couldn’t yet be provided. Also the acceptable level of disturbance is not the same at all airports and in all states. Methods to evaluate the A380 impact on ILS have been developed in France and Germany. If an alternate airport expects to handle diverted A380 operations during low visibility conditions, special attention should be given to this kind of operations. An operational plan must be set up to guarantee that the ILS 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 and taxilanes are implemented. For this, ICAO has specified separation distances for the different aircraft categories and taxiway / taxilane situations. For code F, these minimum separation distances are based on extrapolation of the distances given for code E. However, risk assessment, as well as operational experience with code E aircraft, has shown that large aircraft can be operated safely on taxiways with smaller separation distances than those given by ICAO. AACG recommendations for minimum separation distances are based on these risk assessment and operational 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 object 3. 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 F aircraft. AACG recommend a distance of 91 meters if proper guidance, such as centre line lights or equivalent guidance, is provided for night or low visibility operations. Many alternate airports will have parallel taxiways, which are designed for code E aircraft. A separation distance of 80 meters will in those cases normally be available. This does not mean that the A380 cannot make use of one of the two parallel taxiways. If an A380 operates on one of the taxiways, the other taxiway will 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 when two A380 aircraft taxi on parallel taxiways. The AACG recommends 91 meter, which results in a margin of 11m. In case of an A380 operating at an alternate airport the occasion that two A380 aircraft will pass each other on parallel taxiways is rare. However the maximum wingspan of the aircraft taxiing on the other taxiway in the case an A380 taxies on parallel taxiways separated by only 80 meters can easily be calculated: taxiway separation minus half wingspan of A380 minus margin equals half wingspan of the aircraft on the other taxiway. A study based on measurement with the real aircraft is conducted by several European States. Outputs are expected by the middle of 2006. The ECAC NLA website is intended to reference those studies when available draft 11 ICAO annex 14 requirements: 80 meters – 40 meters – 17.5 meters = 22.5 meters or a maximum wingspan of 45 meters (i.e. aircraft like A310, A300 and B757). AACG requirements: 80 meters – 40 meters – 11 meters = 29 meters or a maximum wingspan of 58 meters (i.e. aircraft like B767 and MD11). Special attention must be given to curved taxiways or turning manoeuvres on taxiways. At all times a minimum 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 margin additional procedural separation must be provided. Proposed alternative measures, operational procedures and operating restrictions for airports that can-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 of 45 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.  Publication in the appropriate aeronautical documentation is required.  Establish appropriate ATC operational procedures. Taxiway centre line to object For 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 that taxiing is more accurate on taxilanes. Although recent taxiway deviation studies have not found any relation between taxi speed and deviations from the taxiway centre line, it is still one of the reasons why ICAO allows smaller clearances on taxilanes. Extra caution on the more congested apron area could also be a factor in better taxilane accuracy. The local authority could allow taxilane to object clearances on taxiways, if necessary with measures such as taxi speed reduction. If these measures can be ensured on the taxiway, e.g. by “follow me” guidance and/or clear publication in the aeronautical documents, it may be acceptable to taxi an A380 on taxiways with less than the required clearances. If proper guidance, like for example taxiway centreline lights, is available, an A380 could be operated on a code 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 of 10.5 meters, or 7.5 meters if proper guidance is available, must be guaranteed. Proposed alternative measures, operational procedures and operating restrictions for airports that cannot comply with ICAO requirements or AACG recommendations related to taxiway – object clearance  Use of code E taxiways with warnings to exercise caution, and possibly reduction of taxi speed (taxiway to object clearance = 47.5 meters)  “Follow me” guidance or marshalling can be used.  Use of taxi cameras when available  In an ultimate step, towing the aircraft can be an option (if taxiway to object clearance less than 47.5 meters)  Publication in the appropriate aeronautical documentation is required and inclusion in the crew documentation procedure Aircraft stand taxilane to object For aircraft stand taxilanes ICAO requires 50.5 meters clearance to any object while AACG recommend 47.5 meters if proper guidance is provided. Further reduction of the separations distances is difficult and will result 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 me” guidance or marshalling but also towing the aircraft are possible solutions. draft 12 Proposed alternative measures, operational procedures and operating restrictions for airports that cannot 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.  Publication in the appropriate aeronautical documentation is required. 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 an Airbus 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 be an issue. As the A380 half wingspan is 7.5m more than a B747-400 the entire 7.5 metre margin is used and safety 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 equipped with fixed installations like passenger bridges and light poles. It is sometimes easier to park the A380 on a remote apron or even the cargo apron as these aprons have fewer restrictions on aircraft size, if a stand at the end of a concourse is not suitable. When parking an A380 on stands where it is not designed for, marshalling is recommended and towing the aircraft 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 does not 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 its own power is possible. Attention should be given to blast issues, especially during non standard taxi-out manoeuvre. Proposed alternative measures, operational procedures and operating restrictions for airports that can-not provide aircraft stands for an A380 that complies with ICAO requirements or AACG recommendations.  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.  Publication in the appropriate aeronautical documentation is required. 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 width For the width of a taxiway bridge, AACG recommends a minimum of 49 meters (ICAO requirement 60 meters minimum). Smaller bridges are acceptable if a proven method of lateral constraint is provided. If the taxiway bridge is designed for code E aircraft, the width of the bridge will be 44 meters minimum. In that case, an A380 can only use that taxiway bridge if lateral constraint is provided. If not, the A380 may not use that taxiway bridge, under its own power. Towing the aircraft over the bridge is a possibility. Connecting and disconnecting time requires consideration. As the number of A380 movements is very low, the operational disturbance may be acceptable. draft 13 Proposed alternative measures, operational procedures and operating restrictions for airports that cannot 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 protection If the width of the taxiway bridge is such that the outboard engines overhang the bridge structure, blast protection of areas below the bridge may be necessary. In case jet blast protection can’t be provided over a width 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 that cannot comply with ICAO requirements or AACG recommendations related to blast protection on taxiway bridges.  Taxing with outboard engines on idle thrust.  In the extreme case the airport authority could require taxiing with outboard engines shut-off (feasibility to be confirmed by manufacturer).  Publication in the appropriate aeronautical documentation is required. Rescue and fire fighting vehicles Access should be provided to allow rescue and fire fighting vehicles to intervene in both directions. This is however not a specific A380 issue. The wingspan of code E aircraft also exceeds the width of a code E taxiway bridge. If the width of the bridge is not enough to provide vehicle passage on the bridge, when occupied by an A380 or any other large aircraft, an alternative path for RFF vehicles must be provided. This path could be a service road with separate service road bridge. On large airports, more than one RFF station is mostly provided. In most cases, a solution could be to intervene from both sides of the taxiway bridge if the RFF stations are not located on the same side of the bridge. Specified response times should be taken into account. If an alternative path for RFF vehicles or response times from one of the RFF stations can not be guaranteed the solution could be to strategically position RFF vehicles on both sides of the taxiway bridge for an A380 passage. As the A380 passage is only occasional, the disturbance of this procedure should be acceptable. Proposed alternative measures, operational procedures and operating restrictions for airports that cannot comply with ICAO requirements or AACG recommendations related to accessibility of rescue and fire fighting vehicles.  Strategically position RFF vehicles on both side of the taxiway bridge. Structural maximum load The 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 case capable of supporting an A380 on arrival. The Maximum Landing Weight (MLW) is less than the MTOW of a B747-400. The bridge should also be capable to support an A380 on departure as the airlines have quoted that the actual take-off weight in practice will be limited to maximum MZFM + 3 hours fuel (comparable to a B747-400 at MTOM). In that case no special procedures are required. The actual take-off weight should be based on the bearing strength of the bridge / tunnel8, using concession procedures if appropriate. For the alternate airport, it is necessary that the actual bearing strength of taxiway bridges and tunnels be published in the appropriate aeronautical publications. Proposed alternative measures, operational procedures and operating restrictions for airports that cannot comply with ICAO requirements or AACG recommendations related bearing strength of taxiway bridges or tunnels.  Publish the weight limitations on A380 taxi routes and inclusion in the crew documentation procedure 8 If the bridge load is severely limited, the airlines involved would have to plan for means of limiting the take-off payload. draft 14 3.10 Taxi routing Specific taxi routes and procedures for diverted A380 aircraft may be necessary to permit A380 operations with the existing airport infrastructure. This may for example involve extra runway occupancy and the provision of turn pads. To specify a taxi route between the runway and the aircraft stand, all the items mentioned in the previous paragraphs should be addressed. As the A380 movement is occasional, the operational disturbance could well be acceptable in relation to the enormous investment for upgrading the infrastructure. As this investment cost will be reflected into the operational charges of the airport, the other airlines will probably accept the occasional disturbance a diversion will cause. To specify a taxi route between the runway and the aircraft stand, all the items mentioned in the previous paragraphs should be addressed. Taxiways If 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 many airports around the world. It is uncommon on airports where parallel taxiways next to runways are provided and where normally traffic volume is high. Back tracking on the runway could in that case not only cause operational 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 A380 movement needs taxing on (part of) the runway. Taxiway bridges The taxi route between an aircraft stand and the runway can contain taxiway bridges or tunnels. As mentioned in paragraph 3.7, taxiway bridges can be critical not only in width but certainly also in bearing strength. If that is the case, it is wise to define taxi routings that bypass the taxiway bridge or tunnel. Sometimes this will not be possible as the only route between runway and terminal area will be over the taxiway bridge / tunnel. In that case, it is advisable to look for a parking position somewhere between the runway and the Taxiway Bridge / tunnel. In the extreme situation this could be part of the taxiway system or even a non used runway. Fortunately, flight diversions are rare. Therefore, the pilot is likely to be less familiar with the airport, its layout 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 services and 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 appropriate aeronautical documentation. 3.11 Other items Besides the mentioned infrastructure items, other issues related to A380 operations at an alternate airport require 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 international regulations. ICAO, FAA as well as JAA have requirements on RFF services on alternate airports. Alternative provisions may be derived for full cargo operations. It is the responsibility of the local authority to determine acceptability of the available RFF services and equipment. The actual availability of the RFF equipment and services should also be monitored by the aerodrome operator in the frame of its Safety Management System and notified by NOTAM in case of difference. b) Snow removal draft 15 The blast issues raised in the “runway” paragraph are also valid for snow removal. It is therefore necessary that airports, which can be filed as an alternate, prepare a plan for runway snow removal based on the characteristics of the A380 (engine span to be taken into account). c) Ground servicing Normally, ground servicing can be achieved with GSE commonly used by other wide body jets (main deck service). Attention must be given for ground service equipment, which can be specific for A380 operations, for example:  A capable tow truck and suitable tow bar at alternate airports where towing the aircraft is unavoidable  Suitable de-icing equipment Some other items of interest  Stairs suitable for large aircraft (around 5m height)  GPU (minimum twice 90KVA)  Refuelling height similar to 777 In the case of a filed alternate, the servicing of the aircraft, its passengers, cargo and baggage should be prepared in advance; the airline should ensure the availability of the relevant handling equipment. draft 16 4. Conclusion For airports that will be an A380 alternate or even have a low number of A380 movements it is clear that it will be financially difficult to fulfil the ICAO requirements and, in most cases, even the AACG recommendations. This document provides a number of alternative measures, operational procedures and operating restrictions that can be implemented to cope with the occasional movement of the A380 aircraft without the burden of high investment cost and infrastructure changes. This is not substantially different than what is already common practice at many airports that accommodate the occasional visit of an airplane bigger than their design aircraft: for example, an An-124, or even B 747 at many existing airports. Implementing the proposed procedures will have an impact on the airport /airside operations and therefore should be analysed carefully. Close cooperation between airport / local authority, ATC services and the airlines 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 be determined, 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 crew and 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  ICAO, New Larger Aeroplanes — Infringement of the Obstacle Free Zone: Operational Measures and Aeronautical Study, Cir 301 – AN/174, December 2005  Common Agreement Document of the A380 Airport Compatibility Group, Version 2.1, December 2002 Additional material of relevance with respect to New Large Aircraft operations is available on the ECAC website (http://www.ecac-ceac.org/nla-forum/index.php), where several states and authorities have decided to make their aeronautical studies available as a reference Information on A380 Airport Characteristics for Airport Planning manual can be found on the AIRBUS website http://www.airbus.com/store/mm_repository/pdf/att00004248/media_object_file_AC_A380.pdf Additional information, not found in this manual, for example preparatory activities on some specific ground handling aspects can be requested at airport.compatibility@airbus.com

qlxiao 发表于 2010-10-22 00:06:04

跟A380有关的资料？

maodun 发表于 2010-10-30 16:38:42

好东西，多谢分享

Anonymous 发表于 2010-12-8 20:39:26

谢谢

看看学习的哦谢谢

srabbitren 发表于 2011-3-2 11:46:07

多谢分享，不知道有没有中文版的

bocome 发表于 2011-7-31 10:20:14

非正常操作

linairm 发表于 2011-10-21 17:50:36

好东西，多谢分享

songsimple 发表于 2012-2-20 18:49:34

谢谢分享拿走学习谢谢楼主

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航空论坛_航空翻译_民航英语翻译_飞行翻译's Archiver

Airbus A380 operations at alternate airports

谢谢