GPS spoofing triggers chaos at Delhi's IGI Airport: How fake signals and wind shift led to flight diversions

GPS spoofing — the deliberate manipulation of satellite navigation signals — has emerged as a major concern for global airlines in recent years. While the issue has mostly affected international routes, it is now disrupting operations within India as well.

According to a report by The Times of India, Delhi’s Indira Gandhi International (IGI) Airport witnessed severe air traffic congestion on Tuesday evening, partly due to GPS spoofing. A sudden shift in wind direction towards easterlies compounded the problem, forcing several incoming flights to divert to Jaipur — even though all four runways at IGI were fully operational.

Data from flight tracking website Flightradar24 showed that IGI ranked second globally that night for airport disruptions, behind only Kathmandu. At least seven flights operated by IndiGo and Air India were among those diverted. The situation was further complicated by VIP aircraft movements during the same period.

Senior pilots told TOI that GPS spoofing was “distracting” pilots and overburdening air traffic controllers. “Most aircraft follow GPS-based area navigation for arrivals and departures. When spoofing occurs, it degrades the aircraft’s navigation capabilities. In such cases, controllers must manually maintain safe separation between planes, leading to heavy radio communication and workload,” a senior pilot explained.

Spoofing works by transmitting fake GPS signals from ground-based sources that overpower or mimic real satellite data, misleading aircraft about their true position. For example, a plane flying over Baghdad might appear to be over Ankara on cockpit instruments.

The problem isn’t new. In October, GPS interference over the Middle East forced an Air India flight from Vienna to Delhi to declare an emergency and divert to Dubai. Due to corrupted signals, the aircraft’s systems — including autopilot, autothrust, flight director, and autoland — all failed. The pilots had to manually fly the plane until landing safely in Dubai, where engineers rebooted its GPS and avionics before it resumed its journey to Delhi.

Flight data shared with The Economic Times by Flightradar24 revealed abnormal parameters during spoofing incidents. Automatic Dependent Surveillance–Broadcast (ADS-B) data showed aircraft positions fluctuating by as much as 335 km within seconds. The Navigation Integrity Category (NIC) value — which measures GPS accuracy — dropped from a normal value of 8 to as low as 0, indicating completely unreliable data.

Globally, spoofing and jamming of GPS signals have become a growing menace for airlines. With modern aircraft heavily reliant on satellite navigation, such disruptions can have cascading effects on multiple flight systems.

In 2024 alone, airlines reported over 4.3 lakh cases of satellite signal jamming — a 62% increase compared to the previous year — underscoring the urgent need for stronger countermeasures and backup navigation systems.