Aviator4u
5th Feb 2011, 18:22
Two aircraft, one flying from Calcutta to Imphal, came on a collision course on Thursday afternoon but a disaster was averted as one of the pilots made a rapid descent following an on-flight alert.
Sources at the Calcutta airport suspect an oversight by the Dhaka airport authorities, in whose airspace the flights came too close to each other.
The Air India flight from Calcutta was carrying 102 passengers. The other flight, of China Eastern Airline, was from Kathmandu to Shanghai.
Sources at the Calcutta air traffic control (ATC) said the Air India flight, an Airbus 319, had taken off around noon and flew 30 nautical miles (55.56 km) before entering the flight information region of Dhaka airport.
“The Calcutta ATC approved a flying height of 31,000 feet for the aircraft. The pilot was flying at that height but he apparently told the Dhaka ATC that Calcutta had approved him 33,000 feet,” said an official at the city airport.
“The Dhaka ATC then told the pilot to ascend to its allotted height of 33,000 feet. We had information — and the Dhaka ATC, too, apparently knew — that the China Eastern Airline was at 33,000 feet.”
The flight from Kathmandu was approaching the Air India Airbus flight path at an angle of 45 degree from the left. “When the two came too close to each other near Comilla in Bangladesh around 12.30pm, the on-flight Traffic Collision Avoidance System (Ticas) issued an alert that they were on a collision course. The Air India pilot immediately descended 2,000 feet,” the official said.
If two aircraft are on a collision course, the Ticas issues various types of alerts depending on their proximity.
“If two aircraft are in less than 40 seconds of Ticas gives a resolutionary advisory, asking the aircraft either to climb or descend away from conflicting aircraft. If its more than that then a mere traffic advisory is given,” said a pilot.
While Calcutta ATC is probing whether actually the Air India pilot was instructed to fly at 31,000 feet. “Dhaka ATC personnel knew that the China Eastern flight was also flying at 33,000 feet so it’s a mystery how they allowed both flights at same level,” said the official.
Sources at the Calcutta airport suspect an oversight by the Dhaka airport authorities, in whose airspace the flights came too close to each other.
The Air India flight from Calcutta was carrying 102 passengers. The other flight, of China Eastern Airline, was from Kathmandu to Shanghai.
Sources at the Calcutta air traffic control (ATC) said the Air India flight, an Airbus 319, had taken off around noon and flew 30 nautical miles (55.56 km) before entering the flight information region of Dhaka airport.
“The Calcutta ATC approved a flying height of 31,000 feet for the aircraft. The pilot was flying at that height but he apparently told the Dhaka ATC that Calcutta had approved him 33,000 feet,” said an official at the city airport.
“The Dhaka ATC then told the pilot to ascend to its allotted height of 33,000 feet. We had information — and the Dhaka ATC, too, apparently knew — that the China Eastern Airline was at 33,000 feet.”
The flight from Kathmandu was approaching the Air India Airbus flight path at an angle of 45 degree from the left. “When the two came too close to each other near Comilla in Bangladesh around 12.30pm, the on-flight Traffic Collision Avoidance System (Ticas) issued an alert that they were on a collision course. The Air India pilot immediately descended 2,000 feet,” the official said.
If two aircraft are on a collision course, the Ticas issues various types of alerts depending on their proximity.
“If two aircraft are in less than 40 seconds of Ticas gives a resolutionary advisory, asking the aircraft either to climb or descend away from conflicting aircraft. If its more than that then a mere traffic advisory is given,” said a pilot.
While Calcutta ATC is probing whether actually the Air India pilot was instructed to fly at 31,000 feet. “Dhaka ATC personnel knew that the China Eastern flight was also flying at 33,000 feet so it’s a mystery how they allowed both flights at same level,” said the official.