This winter, the Airports Authority of India (AAI) will increase the length of its installed approach lighting system (ALS) at the Patna airport so that aircraft could land even when the visibility is 1,000m — ensuring a hassle-free journey for passengers.

This will ensure that the flights land on time in foggy weather and are not diverted to other airports.

ALS extends from the approach end of airstrips. It helps pilots in visual identification of landing environment, and in aligning the aircraft with the runway on arriving at a prescribed point while approaching it.

It significantly enhances the safety of aircraft operations, particularly in conditions of reduced visibility like foggy or rainy conditions.

At present, the approach lights for the Patna airport extends around 210 metres outward from the eastern end of the runway, which allows aircraft to land when visibility is 1,200 metres.

“We are going to extend the approach lights to 420 metres before the onset of winter this year. This will allow aircraft to land even when visibility is 1,000 metres. We have got permission from the state government to install the lights,” Patna airport director Rajender Singh Lahauria said.

Poor visibility had led to chaotic condition at the Patna airport last winter and travellers had to face undue hardships as flights got delayed or diverted.

The airport officials paid attention to the problem and found that the visibility wavered between 1,000 metres and 1,200 metres for several hours during the day, and made them think about extending the length of ALS so that flights could easily land even when visibility is 1,000 metres.

“This is how we thought of extending the approach lights to 420 metres from the place on the runway where inbound flights touch down. It will have a huge positive impact on flights this winter,” Lahauria said.

In the next step, the AAI will extend the length of ALS to 720 metres before the 2019 winter so that flights could land at the Patna airport even when visibility is just 750 metres.

Approach lights are placed at 30 metres distance from each other.

To complete this, the approach lights will have to be installed outside the airport premises, including some on Peer Ali Marg that lies adjacent to the airport, a few at Sanjay Gandhi Biological Park (Patna zoo), and also on the premises of government bungalows along Strand Road in the state capital.

“We have got the required permission from the state government after this issue was discussed at a meeting between Union civil aviation secretary Rajiv Nayan Choubey and Bihar chief secretary Deepak Kumar last month,” Lahauria said.

The Patna airport is one of the most constrained airports in the country.

It has a runway length of 2,072 metres, which gets curtailed to 1,938 metres for approaching aircraft from the eastern end due to the clock tower over the Old Secretariat building, and to 1,677 metres for incoming flights from the western end due to railway electricity traction lines.