FINAL REPORT - Stakeholders - Ofcom

The key is to provide a phased transition:
• fit ground station upgrades into the normal replacement cycle
• choose regions to convert to 8.33 kHz and, if possible, provide assistance to the
affected GA operators. Note that this might involve providing direct funding
assistance to GA operators in return for acceptance by that community of a
mandate to equip by a certain date. Other options include waiting for natural fleet
renewal, a process that could take at least 15 years, or simply issuing a
mandate, in which case all resultant costs are placed on the GA community.
5.11.4 Medium term measures
Possible medium term measures include:
• encouraging the aeronautical community to bring demand for new voice
channels under control through the introduction of more efficient air traffic control
concepts such that the demand begins to level off;
• transferring existing ACARS data to VDL Mode 2
• freeing up VHF spectrum by decommissioning VORs.
The control of demand requires NATS to employ strategies to provide additional airspace
capacity that rely on techniques other than systemisation. In the next 4 years, NATS will
have implemented much of its Mode S programme. This in turn provides the data
necessary to implement some initial controller tools with a resultant increase in capacity.
In the longer term, concepts based on a greater delegation to the pilot offer the potential
to provide much greater airspace capacity without the need to introduce more sectors.
Planning for such a concept is needed now. However no specific recommendation for
Ofcom is made on this issue since it is seen as primarily an issue for the aeronautical
community only.
Recommendation 5.2: The introduction of VDL2 provides an opportunity to transfer
existing ACARS traffic with a resultant increase in spectrum efficiency by a factor of 10.
ATIS services should also be transferred making possible the re-allocation of some of the
spectrum. The introduction of VDL2 also provides an opportunity to introduce some
controller-pilot dialogue services, which are unlikely to result in a decrease of voice
channels but provide a means of preparing for a wholescale transfer in the longer term.
Where parts of the VHF band are to be used for AOC and commercial services in
general, Ofcom should consider administrative incentive pricing to encourage efficient
usage.
Socio-economic factors
This illustration is based on the operations of SITA which are described below.
The SITA AIRCOM Datalink Service today comprises over 650 VHF ACARS stations
deployed in over 165 countries. The SITA VHF AIRCOM Datalink service has over 120
airlines/aircraft operator customers which have over 5,000 VHF ACARS equipped aircraft
that use the service on an almost daily basis, exchanging on average 11.5 million kilobits
per month. Over sixty percent of this traffic is exchanged over the European region where
the service operates on 3 frequency channels.
Over 2,000 (representing seventy customers) of these aircraft are also equipped with
SATCOM avionics that exchange, on average, over 2 million kilobits per month.
Since the early 1990’s an increasing number of air traffic service providers have started to
use the AIRCOM Datalink service to exchange Air Traffic Service related application data
which currently accounts for around 5% of the total traffic exchanged over the service.
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