Current and Planned Progress of 8.33 Khz Channel Spacing Implementation by NATS

AERONAUTICAL COMMUNICATIONS PANEL (ACP)

Eleventh meeting of WORKING GROUP C

Brussels Belgium 20 – 22 September 2006-09-13

Agenda item 8 - AOB

Information Paper on NATS 8.33kHz channel spacing;

Progress and Intentions in the UK

Presented by:

Mr. R. Hughes 

1 Introduction

The demand for new assignments of frequencies in the aeronautical VHF band within the European Core Area continues to be high, driven by:

• The need for airspace restructuring to enhance capacity and reduce delays;
• Increasing demand for other AGA services, such as ATIS; and,
• The need to clear the upper part of the spectrum for data services such as VHF Data Link (VDL).

The introduction to service of a replacement AGA service system is not expected before 2020, by which time, traffic is expected to have doubled over current rates.

A universal implementation of 8.33 kHz channel spacing would alleviate, but not necessarily completely eradicate, the shortfall of frequencies in the interim.

UK airspace contains a number of relatively large sectors, and some with significant over-sea components, where the siting of transmitter stations and the provision of adequate AGA coverage is difficult. Consequently, UK makes extensive use of multi-carrier (CLIMAX) installations for both coverage and redundancy reasons.

EUROCONTROL has put some considerable effort into studying 8.33 Climax operations for 2-leg offset carrier[1]. It is now ready to amend Annex 10 to enable implementation of 8.33 Climax mode throughout Europe.

This paper presents the progress and intentions by NATS Ltd (UK) on implementation of 8.33 kHz channel spacing as well as the potential of 8.33 kHz Climax operations in the London and Scottish FIR.

2 Current operation, 8.33 VEX (FL245)

To date NATS has implemented 8.33 kHz operation on 10 frequencies:

Table 1 Current 8.33 Frequencies operated by NATS

3 Planned implementation, 8.33 VEX Phase 2 (FL195)

NATS is planning to implement a further 10 frequencies following a ‘Feasibility and Options’ study on VEX Phase 2 for FL195. The target date for these frequencies to become operational on 8.33 is early 2008.

The frequencies are:

Table 2 Planned frequencies to be converted to 8.33 by NATS

4 8.33 Climax Operations

4.1 Expansion of VEX Phase 2

Whilst the frequencies for VEX Phase 2 above have been agreed there are a further 10 frequencies that could be converted, 5 of which are dependant on 8.33 Climax mode and 1 of the 10 is as low as FL125.

Table 3 Feasible frequencies to be converted to 8.33 and 8.33 Climax by NATS

4.2 The Massive expansion

Further to all of the channels above, 8.33 Climax operations would enable NATS to convert a total of 47 of its current civil channels down to the base of operation of its sectors. However, without Climax a mere 7 of its channels could be converted.

Table 4 Feasible frequencies to be converted to 8.33 and 8.33 Climax by NATS to base of sector operations

Conclusions

This information paper has detailed the current and planned progress of 8.33kHz channel spacing implementation by NATS Ltd (UK).

Currently NATS is operating ten 8.33 channels with a further ten being planned to be operational early 2008.

With 8.33 Climax NATS could convert a further 57 channels down to the base of sector operations, without Climax the corresponding figure is only 12 channels.

5 Recommendations

The meeting is invited to note the information in this paper.

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[1] WGM 11 WP07 Annex 10 amendments to cover Climax operation on DSB-AM with 8.33kHz channel spacing