Dhaka airport yet to be fog-ready

During winter, passengers at Hazrat Shahjalal International Airport in Dhaka often have to bear untold sufferings following the diversion of flights due to low visibility amid dense fog.

Between November and February, it is a common scenario for flights to divert from HSIA to different airports in India, Bangkok, and even Malaysia following suspended runway operation due to low visibility for hours, causing serious disruption to flight schedules, said a top official of HSIA.

An upgrade of the airport's Instrument Landing Systems (ILS) to Category 2 from the existing Category 1 can provide a remedy to the problem.

However, the Civil Aviation Authority of Bangladesh (CAAB) is yet to get this job done so far.

ILS is a precision runway approach aid based on radio signals and high-intensity lighting arrays that provide pilots with both vertical and horizontal guidance during landing in thick fog.

ILS is a precision runway approach aid based on radio signals and high-intensity lighting arrays that provide pilots with both vertical and horizontal guidance during landing in thick fog.

In January last year, CAAB chairman Air Vice Marshal M Mafidur Rahman said the installation of ILS to ensure uninterrupted flight operation amid low visibility in winter was likely to be completed at HSIA by the following three months.

Since then, one winter ended and another came, but the work still remains incomplete.

Diversion of flights during dense fog not only causes immense suffering to passengers but also results in the airlines concerned incurring losses due to various charges, including landing and parking, imposed by the respective airports, said aviation experts.

"Diverting a flight to a new airport and then returning to Dhaka again also requires a huge amount of fuel, depending on the distance," said a senior pilot of Biman Bangladesh Airlines, wishing anonymity.

"Besides, an extra take-off and landing due to diversion of flights also cause additional costs and need overhauling of the aircraft's engines sooner than the estimated time," he added.

"Sometimes we fly slowly to Dhaka to avoid diversion or hover the aircraft in the sky when we see fog forecasted in the weather report for Dhaka," said another senior pilot of Biman.

"Just because of the absence of ILS-2, we are compelled to waste our time, energy, and money, apart from suffering to passengers and loss to the airlines," said a pilot of Novoair, a private air operator, requesting anonymity.

"In fact, we require a Category-3 ILS system at the country's prime airport when all major ones, including Kolkata airport, have Category 2," he said.

A Category-3 ILS enables a pilot to land even in zero visibility.

"It's unfortunate that the authorities failed to upgrade the Dhaka airport's ILS to Category 2 even after years," he added.

In December, Biman alone had to divert six international flights due to dense fog, sources at the national flag carrier said.

Aviation expert ATM Nazrul Islam said a minimum of 800-metre visibility is a must for pilots to land at the HSIA.

To upgrade the airport, it will need improved ILS, a highly accurate radio signal-based navigation aid giving horizontal and vertical guidance to pilots, he said.

One kind of signal gives the glide path and the other shows the runway's central line, providing the pilot with accurate bearings for landing, Nazrul added.

Contacted, the CAAB chief said all electrical system works for the ILS-2 project, including the installation of lights on the runway, have been completed.

However, the control panel is yet to be installed, he said.

"Also, some interfacing work that will connect to the third terminal is incomplete. Due to this, we may not get the full benefit of ILS Category-2 this winter," he said.

"We have instructed the contractors to complete the work quickly so Dhaka airport achieves ILS Category-2 by this year," he added.