Press clip:

The following article has been converted to HTML format.

VOL 1 NUMBER 10 24 J U LY 1995



A fair hearing for Sweden’s GP&C?

by Anne Paylor

Lufthansa is planning within the next six month to develop an ATM demonstrator which will be based largely on the Swedish-developed Global Positioning and Communications (GP&C) system, with the aim of inaugurating airborne trials soon after.

The Lufthansa effort is part of a growing lobby among elements of the airline community to ensure that the Swedish system - the heart of which is a complex and sophisticated global navigation satellite system (GNSS) transponder - is fully evaluated in the intricate process towards CNS/ATM system identification and not overlooked in the rush to find alternative solutions.

Ludwig Kilchert, Lufthansa's Senior Project Manager, Aircraft Evaluation and Concepts, went so far as to say: 'CNS/ATM will not work without it.'

However, he acknowledged that there would be 'heavy resistance to the system concept because it is very economical" and would inevitably make a large hole in the existing manufacturing base.

Sweden has recently submitted to the International Civil Aviation Organisation (ICAO) draft standards and recommended practices (SARPS) for the self-organising time division multiple access (STDMA) VHF Data Link (VDL) element of its system. But the system as a whole incorporates a full range of CNS/ATM functions which could eventually replace virtually all land-based navigation aids using a single 'box' in the flight deck instead of the multiple box applications which are currently a feature of CNS/ATM implementation.

Cost Savings

The Swedish Civil Aviation Administration claims that it has the potential to replace radar, VOR, DME, ADF, NDB, TCAS, MLS, ILS, ground movement radar, and Mode-S. It also provides a high capacity data link, air-to-air communications, ADS, a differential GNSS facility, and a number of other functions.

Kilchert said he could reel off a list of safety and efficiency improvements that GP&C offers, but perhaps most importantly for the airlines would be its considerable cost savings.

"My dream is system which combines the best elements of the Swedish system with the best elements of the VDR (voice digital radio) currently under development in the US. Then we would have a single system which could replace two thirds of the equipment we currently carry in the flight deck," he said.

The International Air Transport Association (IATA), too, is concerned that GP&C is not getting a fair hearing at ICAO.

"Airlines are facing heavy investment in airborne equipment: we must avoid unnecessary expense and chose wisely," said Ken Somerset, IATA's Regional Technical Representative - Europe. 'When proposals like GP&C are tabled, offering - it appears - significant potential to reduce cost and improve safety and efficiency, we believe there is a duty on all involved in the planning, management, and operation of air transport to give such proposals proper consideration.' IATA wanted, he said, to see it given the urgent consideration it deserved.

Back-up role

Somerset is afraid GP&C may have missed the boat, with systems such as Mode-S, TCAS, etc. already having been specified for the future architecture. He is concerned that having been "once again set aside for future consideration' by ICAO's Aeronautical Mobile Communications Panel (ACMP), only the STDMA element may be able to play a supplemental - but in itself very useful - backup role to the systems now being defined.

The ACMP will not be proposing the draft SARPS in their original form at the next Air Navigation Commission meeting because it feels "the comprehensive presentation of the system to the meeting showed that there were technical or operational areas involved," each of which would need to be considered by a range of specialist panels and committees.

Kilchert, however, believes it is not too late for the Swedish system. 'Mode-S and TCAS in its present form will not survive. There are some people who would say that if the standardisation bodies do not have the flexibility to react to the demands of their customers, they will be ignored. If the airlines want it to happen, they can make it happen," he said.

Although European plans to mandate ACAS by the turn of the century are based on current TCAS 11 specifications, planners have not ruled out the possibility that superior systems may emerge and qualify for application within the future European Air Traffic Management System (EATMS). Somerset says GP&C "provides the pilot with a 'situation awareness' in the cockpit far beyond the capability of systems such as TCAS, "and Kilchert claims that it is "far superior to TCAS.'

The Swedish STDMA is also, according to Somerset, listed as one of the potential data link candidates in the Eurocontrol Plan for future data link requirements in the ECAC region.

In April, airline representatives from Alitalia, Lufthansa, Northwest, SAS, and United, as well as IATA and the Danish Civil Aviation Administration were invited to Stockholm by the Swedish CAA to review from an airline point of view the proposed draft SARPS for the Swedish STDMA VDL. They were also given alive GP&C demonstration.

'The impression I got from the proceedings and the dialogue that took place was one of broad support for the Swedish STDMA proposal, and a positive view that it must be fully considered as an option for the future digital VHF system,' said Somerset who was among the representatives attending.

United believes one of the key attractions of the system is that it is already operational and has been tried and tested over a number of years.

'No other TDMA system I have seen is as far along or as technically advanced as the Swedish system, and it seems to do the key things we need it to do,' said Ed Thomas, Flight Systems Program Manager with United Flight Operations.

Given the very positive reception GP&C consistently seems to receive, the continued question mark over its long term role in the CNS/ATM architecture continues to puzzle industry observers.

Consistently sidelined

One can only speculate as to why this innovative system proposal, which has been widely publicised in the international ATM planning for over the past two years at least, has been consistently sidelined by the engineers and scientists who debate such matters," said Somerset. 'We should not turn away such good technological innovations."

The vested interests of the big avionics manufacturers which are involved in developing the individual elements the system can clearly not be discounted as a potential pressure point.

'However, I think the manufacturers realise that if they resist and fight the advent of such new technology for too long then they will miss the market opportunities it presents," Kilchert said.

Thomas also points out that huge investment in Mode-S on both sides of the Atlantic means there is inevitably resistance to acceptance of anything which might damage its chances of survival.

'Most of the US carriers do not support Mode-S," he said. "it is almost like another MLS. The only objection to the system I consistently hear is that it might not have enough capacity to handle all traffic messages in the densest airspace. However, capacity to a large extent depends on how much information you are trying to put on the link. If we try to get the ADS broadcast system to handle routine operational messages in addition to position reporting, then any system will not have sufficient capacity. We believe that weather, approach information, airfield data, etc. should be handled on a separate ATN data link."

Cost effectiveness

Trials conducted by the Swedish CAA to simulate heavy traffic would suggest that it can handle message load in dense traffic areas, but this is one area of doubt that Somerset would like to see definitively clarified.

'At this stage, I believe that every effort should be made to evaluate and prove (or disprove) the claims made for this system," he said.

IATA’s Regional Technical Office in Europe has recommended to its Technical HQ in Montreal that a full investigative analysis of GP&C should be carried out "to ascertain its potential for - primarily - the VHF digital data link system under consideration by ICAO Working Groups, taking into account also its additional capabilities and its apparent cost effectiveness."

Kilchert stresses that there is another good reason for giving GP&C a fair trial. Most other systems under development are targeted at commercial air transport operators and carry a corresponding price tag. GP&C is targeted at the whole range of GNSS users - of which aviation is expected to account for no more than 5% - giving it a much wider potential market application, which in turn will bring costs down. It is estimated that it could cost only a fraction of the current cost of a FANS-1 package, for example, while at the same time offering considerably more features. If the price is as competitive as expected, Kilchert suggests the general aviation community may also be persuaded to equip, further enhancing safety.

William Fromme, Director of ICAO's Air Navigation Bureau has said that the Swedish system is ahead of its time (see ATC NEWS, 12 June, front page): Somerset disagrees.

"it is our mission to ensure that member airlines - and of course all other aircraft operators - get the best possible ATC service at the lowest possible cost. It is never too early to introduce systems or concepts which distinctly improve capabilities and reduce cost," he concluded.

Published by SKC Communications and Venture International Publishing . C All rights reserved.

Press clip as MS WORD dokument

Return to homepage