Chennai, July 22: Only a catastrophic accident in a "no talk/radio zone" or "dead zone" could destroy an aircraft suddenly, said an experienced pilot with the Indian defence forces, after an Indian Air Force (IAF) AN-32 transport aircraft, with 29 people on board, vanished suddenly from the radar soon after it took off from here for Port Blair on Friday.
"Planes are designed to fly even during an emergency. There will be reaction time to the pilots facing an emergency to send out messages for help or turn towards safety," the pilot, who spoke on the condition of anonymity, told IANS.
According to him, an AN-32 aircraft will not drop down like a stone or vanish into thin air in the case of normal emergency, as there will be reaction time.
"But in the case of a catastrophic threat, the pilots will not have the necessary reaction time," he added.
He said going by information available at present, the IAF craft was off the radar at around 9.16 a.m. after it took off at 8.30 a.m. from the Tambaram Air Force Station near here.
"The aircraft would have reached a cruising altitude of around 23,000 ft and be around 150 km away from the shore," he said.
According to him, an aircraft will not always be on the radar.
"If the distance to be travelled is around 1,500 km, for instance, then there are chances that the aircraft could not be in the radar from the city of departure after say around 300 km. And it would come into the radar on the other side only when it is around 300 km from its destination," he said.
"So effectively sometimes there will be a dead zone of 700 km. In smaller aircraft, the pilots switch on to the high frequency for being in touch," he said.
Coming to the probable cause of its vanishing suddenly, he said: "The possibilities of different catastrophic events happening in the sky cannot be ruled out."
"For example if an aircraft is caught in a strong thunderstorm, then a plane is as good as a paper caught in the storm.
"The storm will throw the plane like a stone," he said.
According to him, there have been instances when an airplane that was flying at around 35,000 feet altitude dropped down to 5,000 feet but regained control after that.
The other catastrophic events that can happen to a plane are: sudden failure of all the engines; devastasting fire; fuel leakage, jamming of flight controls, loss of flight controls due to fire; power and electrical failure and others.
He said in the best case scenario if the AN-32 had come down gradually then it would have been picked up by some radar or the pilots would have the time to react.
"Landing in sea is near impossibility though the craft manufacturers may say so," he added.