The airport lounge is crowded, with thousands waiting to catch their flight. Long queues for security check and one announcement after another adds to the irritation. You finally manage to board your plane and strap on the seat belt. Don’t relax though, for the chaos on the ground is only matched by the mess above.
Over the past 15 months, there could have been at least eight mid-air collisions over Calcutta, according to the directorate-general of civil aviation (DGCA). That is, eight pairs of planes came within 2,000 feet of each other in air, which constitutes a near-miss in aviation terminology.
Aircraft are equipped with an Traffic Collision Avoidance System (TCAS), which alerts pilots if another plane comes within 40 nautical miles, but that does not rule out a mishap.
“The anti-collision device only alerts pilots if aircraft get too close. But when they do, sometimes there is nothing that can be done. With air traffic on the rise, the risk of mid-air collision has gone up,” said an aviation security expert.
At busier airports, like those in Delhi and Mumbai, on an average, two mid-air collisions are averted every month, said a DGCA official.
Rise in the number of flights (in and out of the city and those flying over it), shortage of Air Traffic Control (ATC) officers and communication problems are behind the mid-air near-misses, stated ATC sources.
According to aviation safety experts, near-misses generally occur due to human error. “A communication gap between ATC officers and pilots are the most common cause of a near-miss,” explained an expert. “In many cases, the officer says something that the pilot does not understand or vice versa.”
A DGCA official echoed him: “Some of the pilots don’t know English well. This results in major problems.”
An official of Jet Airways, which employs several pilots from abroad, admitted: “All our pilots understand and speak English, but the accents vary widely.”
The near-misses over Calcutta were probed and the ATC officers involved were provided “corrective training”. But they cited a more basic deficiency. “Most of us have to work beyond duty hours and are under great stress,” said an officer.
The air traffic has gone up steadily, with 700 planes flying over Calcutta and 190 taking off and landing at the airport every day. The number of ATC officers, however, has remai-ned almost constant. There are about 130 ATC officers in Calcutta, but at least 300 are needed, said airport sources.
The Air Traffic Controllers’ Guild (India), eastern region, has written to the Airports Authority of India, seeking more staff.
“At least two trained officers are needed for direct communication with pilots. But most of the time, there is only one trained ATC officer at the control point,” said an officer.
“Also, the work demands absolute concentration, but a person under stress cannot concentrate,” he observed.