The Alarming Return of GPS Spoofing

A system glitch and suspected spoofing incident at India’s busiest airport lay bare the fragility of modern aviation.

Modern aviation depends on signals so precise they leave no room for mischief. Yet, recently, Delhi’s skies briefly slipped into something close to chaos when a critical system failure compounded by suspected GPS spoofing forced controllers at India’s busiest airport to navigate blind. Nearly 800 flights were delayed, radar screens lost vital data and pilots were left switching to old-fashioned radio beacons. The incident is a wake-up call about how vulnerable India’s airspace is to increasingly sophisticated electronic interference.

For the uninitiated, GPS spoofing is a well-known cyber technique in which an attacker broadcasts a counterfeit satellite signal stronger than the genuine one. As GPS receivers are designed to latch onto the strongest signal available, the device begins to calculate its position not from an orbiting satellite but from the attacker’s transmitter. This differs from the more familiar jamming, which simply blocks a signal; spoofing misleads rather than silences. For ships, aircraft, drones, telecom networks and financial systems that rely on precise timing and location, the implications are severe. In aviation, which depends on accuracy to keep craft separated and properly routed, spoofing is downright dangerous.

Security threat

A spoofing attack typically unfolds in stages. First, the attacker mimics the structure of legitimate GPS signals. Then, by gradually increasing power, the fake signal overwhelms the real one. The receiver, unable to distinguish the authentic from the bogus. locks onto the counterfeit stream, recalculating its position based on false coordinates. In the wrong hands, such manipulation could divert containers at sea, misroute aircraft or compromise the timing systems that underpin everything from telecom towers to stock exchanges. Even personal smartphones could be tricked into offering false locations, enabling identity theft or data breaches. It is little wonder that governments treat spoofing as a national-security threat.

India received a sharp reminder of that on November 6. That evening, controllers at the Delhi Air Navigation Services Centre (DNAS) began noticing missing flight-plan data on their terminals. Within minutes, it became clear that the Automatic Message Switching System (AMSS) - the core platform responsible for routing and processing flight plans across India’s airspace - had stopped transmitting information. Without AMSS, controllers could see radar blips, but nothing about the aircraft behind them: not their flight paths, not their altitudes, not their intended routes or departure data.  Controllers were manually verifying each position and giving clearances one by one. For one of the world’s busiest airspaces, that is aviation’s equivalent of reverting from autopilot to pencil and paper.

The consequences were swift. Nearly 800 flights were delayed as processing speed collapsed; each flight plan had to be recreated, verified and cross-checked manually. What should take seconds stretched to several minutes per aircraft. India’s air-traffic system, which handles more than 1,500 daily flights in the Delhi region alone, ground into an uncharacteristic crawl. The Airports Authority of India (AAI) later described the glitch as unprecedented.

Around the same time, pilots flying near Delhi began reporting possible GPS spoofing. In such situations, crews must abandon satellite-based navigation and revert to older, ground-based aids such as the Very High Frequency Omnidirectional Range (VOR) system, which uses fixed radio beacons to guide aircraft. Air-traffic controllers, already burdened by a crippled flight-data system, had to provide headings manually until aircraft systems stabilised. It is a tedious business even in routine circumstances. When paired with a major systems outage, it becomes a safety concern.

The Ministry of Civil Aviation, sensing the seriousness of the matter, acted quickly. Rammohan Naidu, the aviation minister, ordered a full root-cause analysis and asked the AAI to deploy additional backup servers. He also instructed the agency to accelerate its long-delayed shift from AMSS to a newer Air Traffic Services Message Handling System (AMHS), which provides automatic failover between servers and is designed to better withstand disruptions. A joint team comprising the ministry, the AAI and the Electronics Corporation of India Ltd (ECIL) has been tasked with monitoring system performance and ensuring that safeguards are strengthened.

Yet it is the involvement of the National Security Adviser’s Office headed by Ajit Doval that underscores the gravity of the incident. Spoofing is not merely a technical malfunction but often a sign of hostile probing, either by criminal groups seeking to misroute cargo or by state-linked actors testing vulnerabilities. India cannot afford laxity in an era when GPS interference has been reported near conflict zones in the Middle East, the Black Sea and parts of East Asia. Some European airports have also recorded rising incidents of GPS spoofing believed to emanate from electronic warfare activity.

High risk

The Delhi episode suggests that India’s aviation infrastructure remains highly exposed. The country’s growing reliance on satellite navigation without equally robust layers of redundancy invites trouble. Modernising ATC systems, installing hardened navigation equipment, training controllers in spoofing-response protocols and conducting periodic cybersecurity drills are no longer optional. They are core requirements of a resilient aviation network.

Aviation history is littered with reminders that most disasters stem not from a single failure but from cascading ones. India was lucky this time as no lives were endangered. But the system’s veneer of reliability was exposed as far thinner than assumed.

The aviation world has long been guided by the words attributed to Captain Alfred ‘Lamps’ Lamplugh: “Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.” Delhi’s recent troubles offer India a chance to heed that warning.

(The author is a retired Naval Aviation Officer and a defence and geopolitical analyst. Views personal.)