After years of delays, Dhaka’s Hazrat Shahjalal International Airport finally upgraded its instrument landing system (ILS) from Category-1 to Category-2 in mid-2025. This high-tech system allows aircraft landings in thick fog or adverse weather with visibility as low as 300 to 400 metres. Last month, however, a Thai Airways aircraft struck the newly installed ILS-2 system, rendering it inoperable and disrupting flight schedules.
Flights now struggle to land at the capital’s sole international airport during foggy conditions, forcing diversions to alternative airports. Eight flights were diverted on Saturday and five on Friday after failing to land in Dhaka. Yesterday morning brought further delays for multiple arrivals and departures due to fog. Passengers are facing increasing delays as a result, while airport operations are becoming increasingly complex.
Aviation authorities warn that without swift repairs to the damaged ILS-2, this winter’s fog could exacerbate travel chaos. Civil Aviation Authority of Bangladesh officials confirmed that restoring the technology will take more than three months.
Originally installed around 1980 to assist landings in adverse weather, Shahjalal’s Category-1 ILS grew obsolete over time, according to CAAB sources. It proved ineffective during dense fog, making seasonal flight disruptions routine. CAAB upgraded the system this year to Category-2, enabling landings with 300 to 400 metres visibility. But the Thai Airways incident damaged ILS-2 just before winter, compounding existing winter delays at Shahjalal.
Asked about the damage, CAAB member Air Commodore Md Noor-e-Alam explained to Bonik Barta, “Instrument landing systems feature lighting arrays. For ILS-2 to function, lighting systems must operate at 95 percent efficiency. After the Thai Airways incident, effectiveness has dropped to 84 to 87 percent. Several lights were destroyed.”
Replacement lights require custom manufacturing, Noor-e-Alam noted. “These aren’t standard off-the-shelf items. We must order customised units from the manufacturer, then install them—a process demanding an estimated three-month lead time. We’ve already invited tenders; bids open today, December 29. With evaluations due by Thursday, we hope to issue work orders immediately.”
He warned that full ILS-2 functionality this winter seems unlikely. “We’ve explored alternatives and contacted multiple suppliers. Ready-made lights meeting specifications simply aren’t available.”
Manual landings require a minimum 500-metre visibility. ILS technology guides aircraft when fog reduces visibility. But industry sources state Shahjalal’s old ILS-1 proved unfit for adverse weather, while even ILS-2 fails when visibility falls below 50 metres—necessitating the more advanced ILS-3 system.
CAAB Chairman Air Vice Marshal Md Mostafa Mahmood Siddiq confirmed the airport now relies on the older ILS-1 following lighting system damage. “We had upgraded to Category-2,” he told Bonik Barta. “A few days ago, a foreign aircraft caused the damage. Repairs are underway.”