Navcom Consult GmbH

A380 - simulations of the electrical Aspects for the Airports and ILS (a case study)

The civilian air-traffic is still steadily increasing. As a result, many new large hangars for the A380, new terminals, control towers and other buildings of the infrastructure are built. The existing infrastructure has to be checked for compatibility and the layouts of newly planned or expanded airports are adapted. These building activities need a competent evaluation of the objects, of the existing airport layout and of the existing systems (e.g. Instrument Landing System ILS-subsystems and Radar systems such as the primary ASR/PSR or the secondary radar SSR/MSSR), if the system requirements can be or will be affected in an unacceptable way after the construction of these objects. The answer for these questions has to be given in advance by reliable predictions before the buildings are realised and before the new challenges have to be met. It must be considered also that the classical and worldwide introduced ILS will be in service for a long time. It is meanwhile a known fact that the satellite systems (GPS, Galileo) need at least for CATII/III operation a backup system, i.e. the proven ILS or the MLS.

For all these tasks NAVCOM Consult is offering an adequate and competent consultancy service on the highest state-of-the-art level applying the most advanced numerical methods embedded into the self de¬developed so-called IHSS (Integrated Hybrid System Simulation).

The appearance of the A380 - Electrical consequences for ILS

Part of this airport expansion scheme is the operational appearance of the New Large Aircraft (Airbus A380) in some years (Fig. 1). The aircraft itself is already in an advanced R&D-status and has flown already successfully. The most impressive and relevant features of this aircraft are the huge dimensions of the class F size. This is in particular the huge vertical tail fin which has an upper maximum height of 24.1m. Even larger versions are studied. Hence, the effects of this aircraft have to be evaluated with regard in particular to CATIII ILS operation taking into account the specifics of a given airport. These specifics are:

• Characteristics of the currently installed ILS, for the ILS-Localizer as well as the glideslope in many different scenarios /1-3/.
• Actual operational system characteristics, i.e. the existing DDM system margin to the tolerance limits
• Characteristics of the layout of the airport - in particular the distances of the parallel taxiways to the runway centerline and of the taxiways in the back of the Localisers. The acceptability on a given airport has to be evaluated with regard to ICAO Annex 10 (electrical guidance issues) and to ICAO Annex 14 (obstacle clearance issues).

The former is shortly discussed here only.

The layout of airports is in most cases adapted to current requirements for the most challenging aircraft, i.e. the B747 and not yet to the requirements of the A380. Often the electrical challenges for the ILS are not considered or at least underestimated. Many airports have a limited space and cannot be modified in the potentially required way. Particular problems will be the definition of the safeguarding areas (critical, sensitive areas) and of the holding points. It is evident that often the rolloff taxiways may be in conflict with the longitudinal length of the critical areas for all operational categories.

Safeguarding areas - simulations and numerical results

As part of a larger systematic study some selective results shall be highlighted here:

1. the level of the threat by the A380.



2. the need for an adequate simulation effort by using the suitable state-of-the-art methods combined with the appropriate know-how related to the physics, to the numeric's and to the ILS-system.

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1. Passenger transfer by bus or mobile-lounge between terminals and planes parked on a remote parking



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Summary and Consequences

It has been shown that the threat by A380-aircraft is real for the CATIII-ILS depending on the scenario. Even for the best available systems studies are recommended when the A380 is taxiing on parallel taxiways up to more than 200-metres’ distance. It has been shown also that the application of insufficient methods, which are not state-of-the-art, can result in costly operational restrictions and potential layout modifications which are not physical and not necessary. For more information contact NAVCOM Consult.

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