Shanwick Oceanic Control
The Shanwick Oceanic Control Area abuts Reykjavik Oceanic Control Area to the north, Gander Oceanic Control Area to the west and Santa Maria Oceanic Control Area to the south. Shanwick also has eastern boundaries with the Scottish, Shannon, Brest and Madrid domestic Flight Information Regions.
Prior to 1966, the United Kingdom and Ireland both provided ATC and Communications services in the same area of the North Atlantic. The air/ground communication station at Ballygirreen, near Shannon, worked to the ATC centre at Shannon and the communication station at Birdlip, Gloucestershire worked to the ATC centre at Prestwick, Ayrshire, Scotland. This caused duplication of work and an agreement was reached between the UK and Irish governments where Prestwick and Ballygirreen would work as one unit. Prestwick assumed the ATC (Air Traffic Control) function and Ballygirreen assumed responsibility for communications. Hence the name Shanwick originated, SHANnon and PrestWICK being the original ATC providers.
Responsibility for the provision of air traffic services within International Airspace is delegated to UN Member States by the International Civil Aviation Organisation (ICAO). ICAO divides such airspace into Flight Information Regions, parts of which may be deemed Controlled airspace and, where appropriate, classified as an Oceanic Control Area (OCA).
The flight control (Procedural ATC) aspect within the Shanwick OCA is the responsibility of the United Kingdom and is provided by NATS from the Prestwick Centre and the voice communication aspect is shared between the CDO's (Clearance Delivery Officers) based at Prestwick Centre and the Irish Aviation Authority (IAA) from Shannon Aeradio, based in Ballygirreen Radio Station. Shanwick Control further delegate oceanic control of traffic in the NOTA (Northern Oceanic Transition Area) and the SOTA (Shannon Oceanic Transition Area) to Shannon Control, and traffic in the BOTA (Brest Oceanic Transition Area) to Brest Control.
Shannon Aeradio establish radio contact with flights within the Shanwick OCA by means of HF radio. HF can provide global coverage due to its ability to reflect (see refraction) off the ionosphere and can span the globe in a series of skips. VHF coverage however is normally limited to line-of-sight range.
Shannon Aeradio, callsign "Shanwick Radio", utilises over 20 HF channels and 2 VHF channels. At peak times it can communicate with in excess of 1600 aircraft during a 24-hour period. Shanwick Radio maintain HF communications with all flights within the Shanwick Oceanic Control Area and are responsible for issuing voice clearances to those flights unable to contact Shanwick Oceanic directly.
Using the callsign "Shanwick Oceanic", the Prestwick Centre has 2 dedicated VHF frequencies specifically for the issue of Oceanic Clearances to westbound flights entering the Shanwick OCA, and also provides an ACARS based system called ORCA – Oceanic Route Clearance Authorisation – for suitably equipped aircraft to obtain such clearances without the need for voice communications.
During October 2009, NATS transferred its Oceanic ATC operations from the former Prestwick Oceanic Area Control Center (OACC) into the £300m Prestwick Centre. The Prestwick OACC had been located within the Scottish & Oceanic Area Control Centre, (ScOACC), at NATS' Atlantic House facility, adjacent to the Prestwick Centre. The Prestwick Centre is also home to the Scottish Area Control Centre, (including, since January 2010, the former Manchester Area Control Centre).
Oceanic ATC operations at the Prestwick Centre are undertaken using the joint NATS/NAV CANADA designed ATC flight data system known as GAATS+ – Gander Automated Air Traffic System +. GAATS+, has been in service with NATS since November 2014. (Located close to Gander International Airport, Newfoundland, Canada, is the NAV CANADA Gander ATC center which is responsible for flights in the northwest part of the North Atlantic.) GAATS+ enables controllers to maintain accurate flight data, undertake communications with flights and electronically communicate with adjacent ATC units.
During 2005/06, upgrades to Shannon Aeradio equipment at Ballygirreen took place and the IAA entered into an agreement with the Flugstoðir (ISAVIA) subsidiary Gannet ATS Communications to provide additional HF communication services within the Shanwick OCA via the Gufunes Telecommunications Centre, (in Reykjavík, Iceland).
During the summer, Shanwick will typically handle 1400 flights per day. Approximately 80% of flights within the North Atlantic region fly through Shanwick airspace.
Approximately 80% of flights within Shanwick airspace communicate directly with Shanwick using ADS-C and CPDLC. These systems permit removal of the voice aspect of communications. However, there is still a requirement for all aircraft within Shanwick to maintain HF contact with Shanwick Radio.