There have been numerous successful attempts to jam civilian aircraft communications in Irish-controlled airspace in recent years, including at least one incident originating with Russia, Government records show.
Government documents obtained by The Irish Times detail one incident where a signal traced to Russia blocked a high-frequency radio channel. The channel is used by Irish air-traffic controllers to communicate with commercial aircraft over the Atlantic in emergency situations.
The incident, which occurred just before 9pm on September 9th, 2022, rendered the frequency 5583 kHz unusable for communications.
In response the Irish Aviation Authority (IAA) radio operations based in Co Clare were forced to open a new communications channel and take “mitigation measures”.
RM Block
Russia has been engaged in the jamming of civilian aircraft communications and GPS signals since the start of its full-scale invasion of Ukraine in February 2022.
Some of this activity is a spill-over from attempts to block Ukrainian drones on the battlefield. However, there have also been deliberate attempts to interfere with civilian aircraft.
In September the EU accused Russia of jamming the navigation system of an aircraft carrying European Commission president Ursula von der Leyen as it was attempting to land in Bulgaria.
Irish-registered commercial aircraft have also been affected and on at least one occasion, the GPS system of a jet aircraft carrying Irish Government officials was jammed over Poland, sources said.
However, until now these incidents were thought to be confined to eastern Europe.
The 2022 radio jamming incident affected a large number of commercial aircraft in the Shanwick Flight Identification Region, a large area covering the eastern half of the Atlantic Ocean that comes under Irish responsibility.
Flight traffic in the area, which includes the majority of transatlantic flights, is controlled by the Irish Air Navigation Service, which took over management from the IAA in 2023.
Details of the jamming incidents are contained in internal communications released by the Department of Transport following a request under the Freedom of Information Act. The records were extensively redacted.
An email detailing the September 2022 incident was sent by a department official to members of the National Civil Aviation Security Committee. This included officials from the Departments of Defence, Justice and Foreign Affairs, as well as senior members of An Garda Síochána.
The document says there have been other instances of jamming of the frequency, although it does not say where this jamming originated.
These incidents were judged by officials to be “low risk”. However, it was decided they should be referred to the International Civil Aviation Organization, which regulates global air travel.
The documents also detail several other interference attempts in 2022, which prompted officials to issue a warning to pilots of potential dangers. This is known as a “notice to airmen”.
There were a “significant number of reports” of unknown people sending “spurious” messages to aircraft while travelling through the Irish controlled area, the documents state.
These messages, known as SelCals (selective calling), are sent to pilots by air-traffic controllers to alert them to open up a radio channel for communication. Between October and November 2022, there were three official reports of fake SelCals from pilots in the Irish-controlled zone.
An aviation source described these incidents as akin to “prank phone calls” to aircraft. They pose little danger on their own but demonstrate an ability to interfere with aircraft communications at will.
According to the documents, IAA engineers determined the messages were “not being generated by any equipment locally”. They came from human-generated sources, they said.
Officials also noted the calls coincided with “harmful interference” experienced by aircraft in recent weeks in other areas of the north Atlantic. If they received such a message, pilots were advised to alert Shanwick, who could “tactically manage a change of frequency if required”.
