FINAL REPORT - Stakeholders - Ofcom

mechanisms to provide more airspace capacity and this in itself will provide a brake on
the demand for channels.
New operational concepts which could provide more airspace capacity without increasing
the demand for voice channels include:
• Greater automation of the controller processes. A variety of controller tools are
being developed to assist the control process. Many of these rely on improved
surveillance data, such as that provided by Mode S enhanced surveillance (see
Chapter 3). Through its current radar procurement programme, NATS will put in
place infrastructure that can provide suitable surveillance data. It is believed that
NATS is also intending to introduce an initial suite of controller tools based on
this infrastructure which should at least slow down the requirement for more air
traffic sectors in the time frame 2007 – 2011.
• Larger en-route sectors through a combination of planned trajectories and
successive delegation to the pilot. New concepts are being developed in which
large increases in airspace capacity are provided through a combination of a)
much greater cooperation between ground and air to plan conflict free
trajectories and b) responsibility for parts of the control process being delegated
to the pilot. The details are still be researched and validated but there is the
possibility that the size of air traffic control sectors could actually be increased,
thus lowering the requirement for voice channels in the timeframe 2012+.
5.4.5 AMSS
Although AMSS provides a global service, it is high cost compared with the other links
and hence its use is generally limited to:
• passenger services
• low levels of ATS and AOC traffic in oceanic regions
5.5 Regulatory and Standardisation Issues
5.5.1 HF Communications (R) and (OR)
The planned development of digital communications over power lines, the increase in
cable TV and broadcasting services all lead to considerable pressure on the HF band.
The underlying level of interference is growing, leading to a further reduction in the
performance of HF aeronautical communications.
ICAO would like to protect the current allocations from competing users (examples
include mobile services, cable TV and digital communications via power lines).
5.5.2 VHF Communications Analogue and Digital (R) and (OR)
The main issue is the compatibility of the VHF frequencies (117.975-137.000 MHz) and
the sound broadcasting service in the 87-108 MHz band (i.e. FM radio).
Due to cost issues in retro-fitting, many GA radios cannot handle the additional
frequencies recently allocated for VHF voice – 136-137 MHz. As such, design and
channel allocation needs to take this into account.
5.5.3 Extension of VHF band
Section 3.4.10 highlighted the potential for the decommissioning of VORs operating below
the current communications band. This offers the possibility of establishing new
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