FINAL REPORT - Stakeholders - Ofcom

Where technology choices do exist for the individual user, differential licence fees could
be applied to encourage a move to a more spectrally efficient system. It may be possible
to apply pricing measures to encourage a transition away from NDBs and VORs. In the
UK, this could support the move from point-to-point navigation to RNAV or GNSS-based
navigation. Although civil aircraft have been mandated to move to the new (more
spectrally efficient) solution, exemptions exist for military and General Aviation on the
basis of the cost of upgrading. The problem remains for how to apply pricing – there is no
easy way to tell who is using which en-route navigation aids. The airport domain is easier,
since the tower already charges aircraft depending on which type of approach they use
(ILS, non-precision NDB etc). For this area, additional AIP could be added to the
approach charges, to encourage users to move to a more spectrally efficient solution. In
practice, this would entail applying AIP to NDB approaches, in co-ordination with the
airport’s managing authorities. However, if pricing is to be used, it seems best simply to
charge higher fees to aircraft that are not equipped with DME equipment (the costs for
this were shown above and these could be used as the basis for charging). Given the
long lead times resulting from regulatory and safety of life considerations, a possible
approach is to apply pricing measures with a view to forcing a change over a relatively
long time period (i.e. 10 years). This might mean, for example, applying higher charges to
new aircraft if not equipped with DMEs. Then, the higher charges should be applied after
a 5 to 10 year period to all non-equipped aircraft. This at least provides an incentive for
purchasers of new aircraft and gives a reasonable time for retrofit aircraft to comply.
Recommendation 3.22: Ofcom should recommend to the CAA that a feasibility study be
carried out into the potential for rationalising the DME spectrum to avoid the requirement
for more spectrum elsewhere in the future. In practice, this would entail:
• Looking at long-term allocations for DME, in light of the proposed DME/DME
infrastructure, and the proposed implementation of the GNSS L5/E5 band (1164-
1215 MHz);
• The feasibility and practical implications of the de-pairing of VOR, DME and ILS
frequencies should be investigated, to allow better spectrum planning in the Lband;
• The feasibility and practical implications of de-tripling of ILS/MLS/DME should be
investigated, to free up spectrum for more efficient allocations;
• Ofcom should work in conjunction with the CAA to ensure that studies are
undertaken into the possible effects of UAT (ADS-B datalink) on DME
frequencies 11 .
The application of pricing
The requirements of this recommendation are primarily technical in nature and require
initial study by the aeronautical industry. No immediate applications for pricing have
therefore been identified.
3.4.12 Note on Mobile Navigation Aids – Radar Altimeters
Radar altimeters operate in the C-band at 4300 MHz (+/- 100 MHz). This ARNS allocation
(4200-4400 MHz) applies to all three ICAO regions.
Airborne radar altimeters are used at low altitudes to provide a greater accuracy than
barometric altimeters. In particular, they are used in automatic landing systems on
11
Note that it is unlikely that UAT will be implemented in Europe in the medium-term (i.e.
before 2012).
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