Airlines grapple with spike in GPS interference. Experts say it's collateral damage from global conflicts
Flights between Helsinki and Tartu, Estonia, resume June 2, after GPS jamming led to cancellations
Inside the air traffic control tower at Tallinn Airport in Estonia's capital, a team tracks pilots in training as they fly above the Tartu airport, which lies about 200 kilometres south of Tallinn, and about 45 kilometres west of Russia.
As the screen displays the location of the flights underway, a voice comes over the radio asking for permission to descend from the 1,800 metres she is currently flying at, because the GPS signal used for navigation has suddenly disappeared.
"Jammers are working pretty much 24/7," said Mihkel Haug, head of the air traffic control department with Estonian Air Navigation Services.
"We get incident reports every day from pilots. In April, it was more than 600."
Cases of GPS jamming, which is when strong radio signals drown out or interfere with satellite navigation systems, have surged since 2022, after Russia launched its full-scale invasion of Ukraine.
Incidents have increased in Estonia, which resulted in Finnair temporarily cancelling flights to the city of Tartu because they lost access to GPS before landing.
Reports have also spiked around the Black Sea, which is bordered by six countries, including Ukraine, Turkey and Russia.
While aviation and security experts tell CBC News the jamming is concerning, they say it alone doesn't automatically create dangerous situations, as pilots are able to rely on other navigation aids.
However, there is more worry about the increase in GPS spoofing, which is being seen in Europe and in the Middle East. Spoofing is when fake signals can trick navigation systems into thinking they are somewhere else, potentially directing a plane off course.
Aviation groups say the significant rise in GPS disturbance can pose a safety risk, and the industry is grappling with how to mitigate the challenges that have spiked as result of global conflicts.
Finnair flights cancelled
In Estonia, Haug says that wherever a pilot reports the GPS navigation system is down, air traffic controllers stay on high alert, tracking the flight closely to make sure it doesn't deviate from its planned route.
In late April, over the course of two evenings, two Finnair flights had to return to Helsinki after their GPS navigation system stopped working and there wasn't a certified alternative navigation system in place for landing. They lost access to their navigation system when they were flying at around 3,600 metres.
Haug says usually when planes descend, the GPS system resumes working, but in this case it didn't happen. At the time, Tartu airport, which is small and has its air traffic control handled remotely by Tallinn, solely relied on GPS navigation for landing approaches.
In both cases, Finnair decided to divert the planes back to Helsinki and shelve the route until additional navigation tools could be put in place.
After Estonian Air Navigation Services confirmed that a ground based beacon — part of what is known as Distance Measuring Equipment — would work as a secondary navigation at lower altitudes, Finnair made the decision to resume flights.
Pointing the blame at Russia
Estonian officials blame Russia for interfering with the GPS navigation systems and summoned the head of the Russian embassy in Tallinn earlier this month.
While Estonia's Foreign Minister Margus Tsahkna has accused Russia of violating international regulations as part of its "hybrid" warfare, Marek Kohv, a Tallinn based security expert, says the jamming is likely "collateral damage."
"Russia is trying to avoid Ukrainian drones attacking their critical infrastructure and military facilities," said Kohv, who is head of the security and resilience programme at Estonia's International Centre for Defence and Security.
In recent months, Ukraine has stepped up attacks on Russian oil refineries, and sites on the Crimean peninsula, which Russia illegally annexed in 2014.
According to reporting by Reuters, Russian jamming has been able to fend off strikes from glide bombs, which Ukraine acquired from the U.S.
Sources told Reuters that the Ground-Launched Small Diameter Bomb (GLSD) has a navigation system that allows it to steer around obstacles, but it has been targeted by Russian jamming.
Online, the website GPSJAM aggregates daily reports of GPS interference, and colour codes geographic areas that are seeing a high rate of jamming.
Dark red and purple sections cover parts of Estonia, while a large area around St. Petersburg, Russia, is shaded, along with the Russian city of Pskov, which lies further south.
Kohv says he thinks that the jamming affecting Tartu comes from Pskov, which lies about 110 kilometres away, and is home to an elite Russian military unit — the 76th Air Assault Division.
In recent months, Ukraine has stepped up attacks on Russian oil refineries, and sites on the Crimean peninsula, which Russia illegally annexed in 2014.
Online mapping shows there is currently a high rate of jamming around the city of Sevastopol in Crimea.
"Although it's not an attack toward us per say, it still shows you how Russia operates," said Kohv.
"It doesn't care about international agreements and collateral damage."
Jamming and spoofing in the Middle East
But Russia's war on Ukraine isn't the only conflict that has led to an increase of GPS jamming and spoofing.
In the fall of last year, OPSGROUP, an aviation advisory body, highlighted a surge in GPS spoofing around the Middle East, including Iraq, Iran and Israel and the Black Sea.
In one case, the group reported that a plane flying in Iraq nearly entered Iranian airspace without clearance after its navigation systems were "targeted with fake GPS signals."
In another instance, a large business jet had what OPSGROUP called critical navigation failure upon taking off from Tel Aviv at the end of October.
The aircraft temporarily went off course as the GPS system thought it was more than 400 kilometres south of its actual position on departure from Tel Aviv, leading the aircraft toward Lebanon.
"Starting from September, we started to receive a lot of reports of spoofing. That was very new to us," said Cyrille Rosay, a senior cybersecurity expert at the European Union Aviation Safety Agency who spoke to CBC News from Cologne, Germany.
He said in one case, a crew got a fake alert that they needed to pull up because the plane was close to the ground, even though they were in fact very high in altitude.
In January, the International Air Transport Association (IATA), along with the European Union Aviation Safety Agency (EASA) organized a meeting in Germany that included airlines, manufacturers and regulatory bodies to try and address the growing problem.
In a statement issued after the meeting, the IATA and the EASA said that GPS interference can "pose significant challenges to aviation safety."
In the short term, officials say that the aviation industry needs to ensure that pilots and crews know the risks and how to respond to them using alternative navigation systems. They add that there needs to be more work to adapt the certification requirements for navigation and landing systems, and more input from the aviation industry when it comes to designing them.
"We are looking at a big list of possible solutions," said Rasay, who adds that while GPS interference may have an impact on safety in certain circumstances, he doesn't think it has made it unsafe overall.
He compares it to flying in stormy weather.
"You can fly in stormy conditions … but for any stormy condition there's an increase of risk to safety."
"But that doesn't mean it's unsafe to fly."
ABOUT THE AUTHOR
Reuters and Corinne Seminoff