English
The circumstances that led to the fatal crash of Azerbaijan Airlines Flight 8243 on 25 December 2024 are not yet clear, with investigations still ongoing into exactly what happened.
However, one thing we do know is that around 40 minutes into the scheduled commercial flight from Kaku in Azerbaijan, the aircraft encountered GPS interference as it entered Russian airspace en-route to Kadyrov Grozny International Airport.
This could have catalyzed a chain of events that led to a crash landing at Aktau International Airport in Kazakhstan, in which 35 passengers and three crew, including both pilots, were tragically killed.
GPS interference as electronic warfare
We do not yet know the exact nature of the GPS interference the aircraft experienced, but there are indications that at least some of it was transmitted by anti-drone equipment operated by the Russian military.
Reuters reported that the aircraft’s navigation systems were “paralyzed by electronic warfare systems on the approach into Grozny,” noting also that the interference occurred in an area where GPS jamming and spoofing are thought to be used to incapacitate Ukrainian drones.
Poor weather in Grozny caused the pilots to divert and attempt to land in Makhachkala. Once there they performed a go-around due to fog. At some point between that and diverting across the Caspian Sea, these circumstances led to a Russian air defense system opening fire on the aircraft. The crippled aircraft flew over the sea before attempting to land the stricken plane in Kazakhstan. While both pilots tragically lost their lives, their valiant efforts meant 29 people survived the crash.
The crucial “friend or foe” role of ADS-B
A key factor is that the errant GPS signal prevented the aircraft from reporting its position correctly via Automatic Dependent Surveillance Broadcast (ADS-B). This is a GPS-based system that commercial and private aircraft use to publicly report their position, speed and identity.
As a result, unless you could see the aircraft or listen to air traffic control, someone on the ground would not know that Flight 8243 was flying near Makhachkala. If ADS-B had been working, the flight could have been recognized as a “friend”—i.e. a scheduled commercial flight, rather than a military threat.
The foggy conditions at Grozny Airport on the day of the incident may also have been an aggravating factor, preventing the aircraft from being visually identified. Together, these circumstances may have triggered the apparent attack from Russian air defense.
Civil aviation is particularly vulnerable to GPS interference
If malicious GPS interference was a factor in the crash, it is another indication of the serious threat that navigation warfare (NAVWAR) poses to civil aviation, particularly in conflict zones and politically-contested areas.
Signal jamming doesn’t necessarily affect an aircraft’s ability to navigate, as all commercial aircraft have back-up navigation systems for when GPS is unavailable. However, it can have an impact on other GPS-dependent systems, including ADS-B, ground collision warning systems, and flight management systems (FMS).
GPS spoofing—where false GPS signals are transmitted over the air to fool an aircraft’s GPS receiver into reporting an erroneous location—can be more insidious. GPS World has reported the effects of spoofing on commercial aircraft as including “sudden clock resets, false terrain warnings and unexpected flight path deviations”.
This is a particular challenge as many civil aviation positioning systems were not designed with electronic warfare in mind. The use of simple antenna systems, single constellation and single frequency GNSS, a lack of viable backup navigation systems, and the dependence of multiple non-navigation systems on that single source of data make it especially vulnerable.
Civil aviation must protect against the threat of GPS interference
The loss of life in the December air crash again highlights the need to improve GPS reliability in civil aviation. Spirent research shows that GPS jamming and spoofing have become endemic around the world, affecting over 3,000 commercial flights a week. While conflict zones represent the highest risk, malicious GPS interference can—and does—occur anywhere.
Pilots and airlines need advance warning of GPS interference and its predicted impacts, similar to windshear and turbulence warning systems (WTWS). At the same time, GPS receivers and systems that rely on GPS data must be made more resilient to jamming and spoofing attacks.
Spirent has developed a suite of content, products and services to help the industry evaluate the risk of GPS jamming and GPS spoofing, and to take appropriate action.
If you’d like to understand more about the risks to aircraft systems, or if you’d like to talk to an expert about assessing your risk exposure, please do get in touch.
