Dhaka Airport operating flights without satellite connectivity for 2 months

Hazrat Shahjalal International Airport has been operating without satellite connectivity for two months. After the satellite connection was cut, the communication system is being operated using fiber-optic internet connection, raising questions about the flight safety, especially in adverse weather conditions like winter fog.

Although operations are currently running normally, aviation experts warn that the airport is now being mainly operated on a backup system. Possibility of vulnerability is high if the fiber-optic connection fails. However, authorities say they are trying to identify the problem.

Satellite communication systems are very important for air traffic management. Especially when visibility is reduced due to fog, pilots rely on continuous communication with ground-based systems, such as instrument landing systems (ILS), radar and air traffic controllers, to land safely.

Any disruption in these systems increases operational risks and can force flight diversions. Satellite-based Very Small Aperture Terminal (VSAT) systems are helpful for safe and resilient communication for air traffic management. Fiber-optic links usually act as secondary or backup connections in case the satellite link fails.

According to aviation experts, the Bangladesh Civil Aviation Authority (BCAA) is currently operating the air traffic communication system without an active satellite connection. Instead of satellite, communication is being conducted through fiber-optic internet cables which is worrisome.

An aviation analyst said, “Fiber-optic cables are not the primary system, but are supposed to be a backup. If the cable is cut, in case of a power problem or the network is disrupted, then the entire airport’s operations can be severely disrupted.”

Air Traffic Management (ATM) member Air Commodore Noor-e-Alam said, “This problem has arisen due to satellite signal interference. Authorities are still trying to identify the source of the problem."

He said, "The problem is related to satellite jamming. The source has not been identified yet, but it will be resolved. The airport operations are running normally. There has been no disruption yet."

Bangladesh Telecommunication Regulatory Commission (BTRC) confirmed that the problem is related to interference in the frequency spectrum allocated for satellite-based air transport communications.

In an official memorandum, the BTRC said that unexpected signals in the 4540-4546 MHz frequency band caused temporary disruption in the VSAT system used by the CAAB.

This band is allocated for the BS-1 satellite operated by Bangladesh Satellite Company Limited (BSCL). The BTRC’s spectrum monitoring wing conducted the investigation after BSCL requested it.

On October 20 last year, a joint monitoring team of the BTRC and BSCL conducted a field-level spectrum analysis. They detected two short frequency peaks in the affected band using a spectrum analyzer.

However, as the signals were present only for a short time and were not stable, investigators could not identify their origin. As a result, the source of the problem remains unknown.

To prevent future disruptions, the BTRC has recommended changing the operating frequency band of the VSAT system used by the CAAB.

The regulator has suggested allocating a different frequency band to ensure uninterrupted air traffic and aviation-related communications.

A formal letter containing this recommendation was sent to the Managing Director of Bangladesh Satellite Company Limited on December 10. The company was directed to take necessary action.

A copy of the letter was also sent to the CAAB Chairman and senior officials of BSCL.