Bangladesh’s busiest airport is facing growing concern over the reliability of its air traffic communication system, after satellite-based connectivity used for aircraft operations was disrupted and replaced by fibre-optic internet links - raising fresh questions about aviation safety, system redundancy and preparedness during adverse weather such as dense winter fog.
Hazrat Shahjalal International Airport relies on uninterrupted air traffic communication for safe aircraft take-off, landing and ground movement.
While operations are currently continuing normally, aviation experts warn that the airport is now operating on what was originally meant to be a backup system, creating potential vulnerabilities if fibre-optic connections fail.
Why air traffic communication matters
Air traffic communication systems are critical for managing aircraft movements, especially during poor visibility caused by fog.
When visibility drops, pilots depend heavily on ground-based systems, such as Instrument Landing Systems (ILS), radar and continuous communication with air traffic controllers, to land safely.
Any disruption to these systems increases operational risk and can force flight diversions.
Traditionally, satellite-based Very Small Aperture Terminal (VSAT) systems provide a secure and resilient communication backbone for air traffic management.
Fibre-optic links are usually maintained as secondary or backup connections in case satellite links fail.
What has changed
According to aviation experts, the Civil Aviation Authority of Bangladesh (CAAB) is currently operating its air traffic communication system without active satellite connectivity.
Instead, communication is being handled through fibre-optic internet cables.
Experts say this is a worrying development.
“Fibre-optic cables are supposed to be backup, not the primary system,” one aviation analyst said.
“If there is a cable cut, power issue or network disruption - which we often see - the entire airport operation could be severely affected.”
Concerns have been heightened because winter fog already places additional strain on aviation systems.
If communication systems were to fail during dense fog, experts warn, aircraft operations could be suspended entirely, forcing large-scale diversions or temporary airport closure.
What authorities say
Air Traffic Management (ATM) member Air Commodore Noor-e-Alam told Dhaka Tribune that the issue stems from satellite signal interference.
He said authorities are still trying to identify the source of the problem.
“This is an issue related to satellite jamming. The source has not yet been identified, but it will be resolved,” he said, adding that airport operations are continuing normally and no immediate disruption has occurred.
What caused the satellite disruption
The Bangladesh Telecommunication Regulatory Commission (BTRC) has confirmed that the problem involves interference in the frequency spectrum allocated for satellite-based air traffic communication.
In a government memorandum, BTRC said a temporary obstruction occurred in the VSAT system used by CAAB due to unexpected signals in the 4540–4546 MHz frequency band.
This band is assigned to the BS-1 satellite operated by Bangladesh Satellite Company Limited (BSCL).
Following a request from BSCL, BTRC’s Spectrum Monitoring Branch conducted an investigation.
On October 20 last year, a joint monitoring team from BTRC and BSCL carried out field-level spectrum analysis.
They detected two brief frequency peaks in the affected band using a spectrum analyzer.
However, because the signals appeared only momentarily and were not stable, investigators were unable to trace their origin.
As a result, the exact source of the interference remains unidentified.
To prevent future disruptions, BTRC has recommended changing the operating frequency band of the VSAT system used by CAAB.
The regulator suggested allocating a different frequency band to ensure uninterrupted air traffic and aviation-related communication.
A formal letter with this recommendation was sent on December 10 to the Managing Director of Bangladesh Satellite Company Limited, instructing the company to take necessary action.
Copies were also sent to the CAAB chairman and senior officials of BSCL.
The most recent internal note on the issue is dated December 14.
How other airports handle similar situations
At major international airports, redundancy is key.
Airports typically operate with multiple independent communication layers - satellite, fibre, microwave and radio - so that the failure of one system does not affect operations.
During fog, these redundancies become even more critical, as pilots rely entirely on instrument-based guidance and controller instructions.
Aviation experts say Dhaka airport’s current reliance on fibre-optic communication highlights the need for stronger contingency planning.
“Satellite connectivity should be restored as a priority,” one expert said.
“Backup systems should remain backup, not become the main line of defence.”
Why it matters now
With winter fog already disrupting flight schedules and forcing frequent diversions from Dhaka, any additional technical vulnerability could compound operational challenges.
Experts warn that unless satellite communication is restored quickly and system redundancy strengthened, the airport could face serious risks during peak fog conditions.
While authorities insist operations remain normal for now, aviation specialists say the issue underscores a broader need for proactive maintenance, spectrum security and long-term investment in critical aviation infrastructure.
