Thursday night’s mishap at Bangalore airport can occur at Calcutta airport any night.

Not only dogs but also jackals have free access to the two runways and taxi bays at Netaji Subhas Chandra Bose International Airport after dark.

Aircraft run a high risk of colliding with a stray animal while taking off or landing, as in Bangalore, where a Kingfisher Airlines plane hit a dog on the runway and damaged its nose wheel, said city airport officials. Two passengers were injured in the accident.

There are 19 men — known as “bird scarers” — to scare away the feathered trespassers at Calcutta airport. Though their primary responsibility is to prevent birds from getting in the way of flights, they also chase away other animals. But their shift ends at dusk.

“We work in two shifts from dawn but there’s no one to keep a watch on the runway after dark,” said a bird scarer.

The bird scarers wear red jackets (for easy identification by pilots) and burst firecrackers to keep birds away from the area. “We carry sticks to chase away dogs. Even airport officials chase dogs when they see them,” added the bird scarer.

But once night falls, it is common for dogs to stray into the operation area, consisting of the runways, taxi bays and the adjoining open spaces. “At dawn and after a shower, we also see jackals crawling out of the bushes and running across the runways. They probably come out at night, too,” said the scarer.

Pilots often see dogs on the taxi bay in the evening. “Since the aircraft moves slowly on the taxi bay, we can safely apply brakes. There will be a problem if a dog appears on the path of a plane on the runway,” said a senior pilot.

Dogs sneak into the operation area through the 11 airport gates and broken portions of the airport’s boundary wall.

Airport officials alleged that the Central Industrial Security Force personnel manning the entrances were asked to chase away dogs but they do not do so.

“Two canteens run by an airline in the operation area also attract dogs and birds. They feast on food thrown away,” said an official.

Airport officials said bird scarers were deployed in the mid-1980s when aircraft started using jet engines. Windscreens of planes are often cracked and the engines damaged when they are hit by a bird. “That’s why, the runway watchmen were replaced with bird scarers,” said an airport official.

Big birds, like eagles and vultures, which can cause significant damage to planes, fly during daytime. “Nocturnal birds, like owls, are smaller and are not as dangerous for aircraft. Hence, bird scarers are not deployed at night,” explained an airport official.