KOLKATA: The air ambulance bound for Delhi, which crashed half an hour after its take-off from the Ranchi airport, did not send out a distress call before it went off the radar, officials said on Tuesday. Minutes before the crash, the pilot had sought a deviation due to the inclement weather. Officials at the meteorological centre in Ranchi, however, said despite weather warnings being issued, the crew of the ill-fated turbopropeller Beechcraft aircraft did not contact it before taking flight.
Sources at the Kolkata airport also said the plane disappeared from the radar at the Atali point, where the air traffic controller (ATC) at Kolkata was to handover the plane to its counterpart in Varanasi. Located around 90 nautical miles north-west of Ranchi and 104 nautical miles south-east of Varanasi, the Kolkata ATC triggered the alarm after the blip (plane) disappeared from the radar and failed to contact the captain or the co-pilot over the radio.Quoting the controller at the Kolkata ATC, the sources said, “The captain had asked for a weather deviation and was granted. The flight, which was climbing after taking off from Ranchi, had initially asked for an altitude of 16,000 ft. At 7.30 pm, the pilot contacted again and sought permission to climb to 14,000 ft and no further. This was allowed. That was the last conversation the controller had with the flight cockpit. Exactly four minutes later, the aircraft disappeared from the radar.”An aviation expert said a lightning strike may have affected the transponder and electrical systems of the Beechcraft King Air C90A plane. The low flight level of the aircraft may have also led to interference with its VHF system.The head of the Ranchi weather office, P P Baburaj, said rainfall and thunderstorm warnings had been issued at 11 am and again at 5.10 pm for all departing aircraft on Monday.“In the morning, a bulletin had been sent out with a forecast for rainfall and thunderstorms accompanied by lightning in north-west and central Jharkhand. All pilots should have received the warning. At 5.10 pm, we issued a Nowcast of light thunderstorms with rain in some districts in the northwest sector,” the weatherman said.Typically, planes avoid cumulonimbus clouds because they pose severe, life-threatening risks rather than just discomfort. These clouds trigger violent turbulence, cause intense lightning, heavy icing, hail, and extreme wind shear capable of damaging aircraft structure or causing loss of control. For smaller aircraft like a Beechcraft, flying through bad weather can be dangerous.
