Explained: How GPS spoofing disrupted flights at Delhi Airport  

(Representative Image)

For the first time, Delhi’s Indira Gandhi International Airport (IGIA) has been affected by GPS spoofing incidents, resulting in severe disruptions to flight operations and necessitating multiple diversions.

According to a report by the Times of India, the disruptions have worsened in the past few days, particularly when easterly winds blow, prompting aircraft to land from the Dwarka side and take off toward Vasant Kunj. This unusual pattern has added to congestion.

What is GPS spoofing and how it works

GPS spoofing occurs when counterfeit satellite signals are broadcast to mislead GPS receivers. These fake signals trick navigation systems into misreading their true location. Unlike GPS jamming, which blocks signals entirely, spoofing sends false coordinates that can make aircraft or vehicles appear elsewhere on radar.

Such incidents have been reported near global conflict zones — including the Black Sea and West Asia — but this marks the first known case in Delhi’s airspace.

Runway upgrade adds to flight disruption

The situation has been compounded by the temporary withdrawal of the Instrument Landing System (ILS) on IGIA’s main runway, 10/28, which is under upgradation to Category III. The new system will eventually allow aircraft to land in dense winter fog from both ends, but until the upgrade is complete, planes are relying on Required Navigation Performance (RNP), a GPS-based navigation aid.

With spoofing affecting GPS signals up to 60 nautical miles away from IGIA, flight movements have been severely hampered. On Tuesday night alone, five IndiGo and two Air India flights were diverted to Jaipur due to navigation errors.

Congestion and safety warnings issued

The spoofing issue comes at a time when IGIA handles about 1,550 aircraft movements daily. Any disruption quickly leads to airspace congestion. The Automatic Terminal Information Service (ATIS) has issued repeated warnings, advising pilots to stay alert, cross-check coordinates, and switch to alternate navigation systems when required.

Delhi International Airport Ltd (DIAL) and aviation regulators are working to restore ILS functionality on the main runway by November 27. IndiGo has already conducted a test flight on the upgraded system, with findings submitted to the Directorate General of Civil Aviation (DGCA).

“ILS promulgation on the runway needs to be expedited as Nov 27 is a good three weeks away,” an aviation source told the Times of India, stressing that the system’s early restoration is critical to counter spoofing-related risks.

Spoofing: A growing global aviation threat

Experts warn that GPS jamming and spoofing are increasingly used in conflict zones, the former to conceal military positions and the latter to confuse or misdirect aircraft. Spoofed data can deviate by as much as 2,500 km, posing a serious risk to civil aviation safety.

Airlines have begun pre-warning pilots about spoofing hotspots worldwide and advising them to rely on traditional aids like VOR and DME when affected.

Authorities have confirmed awareness of the spoofing problem but declined to comment on its source, citing security concerns. Their immediate priority remains restoring the ILS to ensure uninterrupted operations.

“The only thing that needs to be done is having ILS on IGIA’s main runway 10/28 at the earliest,” the report said quoting an aviation official. Once operational, the upgraded runway will feature Category III systems on both ends, improving the airport’s resilience during poor weather and technical disruptions.