Shanwick Oceanic Control

Shanwick is the air traffic control (ATC) name given to the area of international airspace which lies above the northeast part of the Atlantic Ocean.

Map indicating location of the Shanwick OCA

The Shanwick Oceanic Control Area (OCA) abuts Reykjavík OCA to the north, Gander OCA to the west and Santa Maria OCA to the south. Shanwick also has eastern boundaries with the Scottish, Shannon, London, Brest and Madrid domestic ATC flight information regions.


Responsibility for the provision of air traffic services within international airspace is delegated to United Nations 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.

Prior to 1966, both the United Kingdom and Ireland were selected by ICAO to provided control and communications services to air traffic within adjacent areas of the north east Atlantic. The air/ground High Frequency (HF) radio communication station at Ballygirreen, near Shannon, County Clare, Ireland, provided HF communications to the Irish Aviation Authority ATC centre at Shannon. The HF radio communication station at Birdlip, Gloucestershire, England, provided HF communications to the Civil Aviation Authority (now NATS) ATC centre at Prestwick, Ayrshire, Scotland.

The resulting duplication of work between ATC providers resulted in an agreement being reached between the UK and Irish governments, where Birdlip and Ballygirreen would work as a single unit. The Prestwick Centre assumed the control function of the joint area and Ballygirreen ultimately assumed sole responsibility for HF communications. The name Shanwick is a portmanteau of Shannon and Prestwick.


Responsibility for aircraft in receipt of a procedural control service falls to the Prestwick Centre, where limited voice communication aspect is shared between the CDOs (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 Brest Oceanic Transition Area (BOTA) to Brest Control.

Shannon Aeradio establishes 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", uses over twenty HF channels and two VHF channels. At peak times it can communicate with in excess of 1,600 aircraft during a 24-hour period.[1] 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 two 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 Oceanic Clearance Link (OCL) for suitably equipped aircraft to obtain such clearances without the need for voice communications.

Operations transferEdit

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 Nav Canada designed ATC flight data system, Gander Automated Air Traffic System+ (GAATS+). GAATS+ has been in service with NATS since November 2014. (Located close to Gander International Airport, Newfoundland, Canada, is the Nav Canada Gander ATC centre 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). In June 2015 the IAA announced that a "Virtual Centre" had been introduced into service whereby ISAVIA operated VCCS (Voice Communications Control System) equipment at Gufunes and identical IAA operated VCCS equipment at Ballygirreen can function jointly, as a single "virtual centre", or independently.[2]

Long-range radarEdit

In July 2015, it was revealed the Irish government would purchase a new long-range radar system for the Irish Aviation Authority and the Irish Defence Forces (military) to monitor covert aircraft flying in Irish-controlled airspace, including military aircraft that do not file a flight plan and do not have their transponders switched on. Irish Minister for Defence Simon Coveney said the increased capability would provide greater surveillance of airspace over the Atlantic Ocean which the IAA has responsibility for.[3]

Traffic statisticsEdit

During the summer, Shanwick will typically handle 1,400 flights per day.[4] 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.

See alsoEdit


  1. ^ "Archived copy". Archived from the original on 10 January 2015. Retrieved 14 January 2015.CS1 maint: archived copy as title (link)
  2. ^ Lane, Tony (24 June 2015). "Irish Aviation Authority and ISAVIA Create Worlds First Cross Border Aeronautical Communications Centre". IAA. Retrieved 23 August 2015.
  3. ^ O'Brien, Stephen (5 July 2015). "€10m radar goes to the front line of military shopping list". The Sunday Times. Retrieved 6 July 2015.[permanent dead link]
  4. ^

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