Air India flight AI171 suffered a tragic incident on Thursday as it crashed minutes after take-off in Ahmedabad.
The Ahmedabad-London Air India plane carrying 242 passengers and crew crashed into a medical college complex. At least 204 people have died in the Air India plane crash. According to Air India, of the 230 passengers, 169 were Indians, 53 British, seven Portuguese and one Canadian. The other 12 were two pilots and 10 crew members.
Video analysis of the crash indicated that as the Boeing 787-8 Dreamliner departed, its landing gear remained extended and its wing flaps were fully retracted—an extremely abnormal situation for the critical initial climb phase.
We look at the science behind an aircraft take-off.
SCIENCE BEHIND AIRCRAFT TAKEOFF
Aircraft takeoff is governed by the interaction of four fundamental forces: lift, weight, thrust, and drag.
Lift is the upward force generated primarily by the wings, weight is the downward pull of gravity, thrust is the forward force produced by the engines, and drag is the resistance encountered as the plane moves through the air. For an aircraft to become airborne, lift must exceed weight, and thrust must overcome drag.
The process begins with the aircraft accelerating down the runway as the engines generate thrust. As the plane gains speed, air flows faster over the curved upper surface of the wings and slower beneath, creating lower pressure above and higher pressure below. This pressure differential produces lift, as described by Bernoulli’s Principle, which is essential for the aircraft to rise off the ground.
When the aircraft reaches a critical speed known as rotation speed, the pilot gently pulls back on the control column, increasing the angle of attack—the angle between the wing and the oncoming air. This action boosts lift further, causing the nose of the aircraft to rise and the main wheels to leave the runway. The aircraft then transitions from rolling on the ground to climbing into the sky.
During the climb, the pilot gradually retracts the landing gear and flaps to reduce drag while maintaining enough lift. The engines continue to provide the necessary thrust, and as the plane ascends, the balance of forces is carefully managed to ensure a smooth and safe departure from the ground into stable flight.
In the case of the AI171, the 11-year-old aircraft could be seen from miles away, losing altitude rapidly and combusting in a fiery blaze that sent plumes of thick black smoke spiralling up in the air.
The aircraft climbed just about 625 feet before plummeting to the ground almost immediately.