Cumulonimbus cloud (CB) is known to be very dangerous for small planes as it causes turbulence. On Wednesday night, only 10 minutes from the Delhi airport, the pilot of the nine-seater chartered plane that took off from Patna was battling one such cloud. The 4,700-kg Pilatus PC-12 aircraft that was turned into an air ambulance just fell from the sky. The plane crashed on a house in a residential colony, killing 10 people in all.
According to the met department, CB cloud is very dangerous for small planes. On Wednesday, when the wind speed was high (60kmph), the pilot couldn't maintain balance. Sources in Air Traffic Control (ATC) said after hitting the CB cloud, the plane, a single engine, turbo prop aircraft, started dropping from 14,500 feet.
"The ATC had asked the pilot to maintain a height of 11,000 feet, which it did. Since the plane had a weather radar, the pilot must have learnt about the presence of CB cloud on his path to Delhi airport,” said a source in ATC.
The air ambulance of Air Chartered Services India Pvt Limited had taken off from Patna airport at 8:30pm. It crashed at 10:48pm.
The dead included pilot Harpreet Singh, co-pilot Manjeet Kotani, doctors Dr Sayed Arshad Abbas and Dr Rajesh Jain, nurse Cyril P Joy, patient Rahul Raj and his cousin Ratnesh Kumar. Three women sitting on the terrace of a building on which the plane crashed also died on the spot.
The pilot had requested for priority landing as he was carrying a patient; he was 10 minutes away from Delhi airport.
According to sources, the ATC initially asked the pilot to maintain a height of 11,000 feet. "At this time the direction of wind changed and the plane was caught in the cross wind. The pilot was then asked to approach the airport from Dwarka side instead of Mahipalpur," the source added.
But a few minutes later, the ATC heard the pilot shouting "bad weather" and the transmission was lost. The pilot had seen a CB cloud. The plane reached 14,500 feet and was asked again by ATC to maintain a height of 11,000 feet but the communication was lost by then.
The source said, " The plane dipped to 7,500 feet and then it went off the radar screen.”
The source added that five minutes after it lost contact with the plane the Faridabad fire department called to inform about the crash.