Rising skylines squeeze airport safety buffers

The tragic crash of Air India Flight AI171 near Sardar Vallabhbhai Patel International Airport in Ahmedabad has turned the spotlight on a longstanding but often overlooked threat to air safety in India — the choking proximity of high-rises and dense construction to the airport funnel area.

As investigators probe the cause of the Boeing 787-8 Dreamliner’s fatal descent shortly after takeoff on 12 June, which killed 265 people, including 241 passengers and crew, experts are raising concerns about how the encroaching urban landscape may have worsened the disaster. The aircraft crashed into a congested locality within minutes of departure, leading to significant loss of life and damage on the ground.

Aviation observers suggest that the presence of more open space around the airport might have reduced on-ground casualties. “When an aircraft is forced to make an emergency landing shortly after takeoff, having open, obstruction-free zones can be the difference between a controlled crash and a catastrophe,” an aviation safety analyst said.

Ahmedabad’s airport, like many older airports in India, sits amid dense development. While its main runway measures 3,505 m — technically sufficient for long-haul aircraft — its surrounding environment leaves little room for emergency manoeuvres. Urban encroachment into the funnel area, the critical zone aligned with the flight path of arriving and departing aircraft, means that even routine operations carry heightened risk.

This is not unique to Ahmedabad. At Patna’s Jayprakash Narayan International Airport, a 56-m high British-era clock tower near the approach path has long obstructed full use of the already short 2,000-m runway. In Lucknow, authorities have identified 624 obstacles — including mobile towers, electric poles, and religious structures — within a 20 km radius of the airport.

Even relatively newer airports are not immune. The Kempegowda International Airport in Bengaluru, a modern greenfield facility once surrounded by open tracts of land, is witnessing rapid changes. What was once a buffer zone of agricultural land and low-rise housing is now being filled with high-rise residential and commercial towers, as the city expands northwards.

This trend, driven by population growth, infrastructure projects, and increasing demand for real estate, is gradually reducing the safe perimeter around the airport.

Urban planners caution that unless zoning controls are strictly enforced, even airports designed with safety buffers will face the same challenges that plague older ones.

City-to-city disparity in height regulations

Analysis of Airports Authority of India (AAI) data reveals wide disparities in permissible construction heights near airports. For instance, at a distance of 4 km from the airport, the maximum approved building height is only 17.87 m in Mumbai — compared to 42.14 m in Vijayawada. Cities like Ahmedabad and Lucknow show minimal increase in height allowance with distance, while others like Chennai and Bhubaneswar are more generous the farther out one goes.

These inconsistencies in height thresholds complicate compliance and weaken uniform enforcement. “Without a national standardised approach, the responsibility of safeguarding the air funnel is falling through the cracks,” a former AAI official said.

The new Bhartiya Vayuyan Adhiniyam (Aircraft Act) 2024 seeks to address these challenges with enhanced powers for regulators. It mandates stricter penalties for NOC violations, allows for immediate grounding of aircraft where safety is compromised, and aims to plug regulatory loopholes. However, industry watchers argue that laws will remain toothless unless implemented uniformly and in collaboration with local authorities.

Greenfield airports offer hope — but for how long?

Greenfield airports, developed on previously unused land, have long been seen as the answer to the congestion and safety challenges plaguing legacy city airports. With ample land banks and carefully planned approach paths, these airports initially offer wide buffer zones, better adherence to obstacle limitation surfaces (OLS), and scope for future expansion.

India has embraced this model, with successful examples like Hyderabad’s Rajiv Gandhi International Airport, Bengaluru’s Kempegowda International Airport, and the newly inaugurated Mopa Airport in north Goa. Each of these was designed to meet modern aviation safety norms and to remain insulated from the risks posed by haphazard urban growth.

In Hyderabad, the area around the airport — once flanked by open terrain and low-rise structures — is now seeing an influx of commercial developments, warehouses, and gated communities.

Similar patterns are unfolding in Bengaluru, where the northern corridor surrounding Kempegowda International Airport has transformed into a high-growth zone. What was once largely a rural area is now peppered with tech parks, high-rises, and large-format residential townships. Experts warn that this unregulated vertical growth is beginning to compromise the air funnel area, echoing the issues faced by older airports.

Even Mopa, India’s newest greenfield airport, is not immune. Within months of its inauguration, real estate interest has surged in the surrounding talukas. With tourism as a major economic driver in Goa, demand for hotels, holiday homes, and commercial projects near the airport is mounting — raising concerns that the safety advantages offered by its initial planning may be gradually eroded if proactive land-use regulation is not enforced.

Aviation experts say that without long-term urban planning and zoning laws that protect air corridors from encroachment, greenfield airports risk repeating the same mistakes of their predecessors. “The initial promise of safety and expansion can be undone in a decade if we allow unregulated growth to creep in,” a senior AAI official said.

The Ahmedabad air crash has reawakened calls for integrated urban and aviation planning. Experts argue that ignoring runway length limitations, overlooking height restrictions in the funnel area, and failing to preserve buffer zones around airports all but guarantee future tragedies.

As India’s aviation sector grows, so too must its commitment to airspace safety. The question is whether policymakers and city planners will act decisively — or continue to allow high-rises to rise unchecked, even in the shadow of the runway.