The Aircraft Accident Investigation Bureau (AAIB) report on the Air India plane crash, released on Saturday, revealed that the fuel cutoff switches for both engines were inadvertently moved from RUN to CUTOFF—one after the other, within a span of just one second—at an altitude shortly after liftoff.
Such an unexpected dual engine shutdown should have automatically triggered the deployment of the Ram Air Turbine (RAT), which is designed to provide essential electrical and/or hydraulic power to maintain control and enable a safe landing. This raises a critical question: why didn’t this backup system help facilitate at least a crash landing that might have saved lives?
A Ram Air Turbine (RAT) is a small, deployable wind-driven turbine used as an emergency power source in aircraft in the event of a complete or partial loss of the aircraft’s primary power systems.
The RAT is typically a small propeller-like device mounted in a compartment on the fuselage or wing. When deployed, it uses the ram air (airflow due to the aircraft's forward motion) to spin the turbine.
The spinning turbine drives a generator (for electrical power) or a hydraulic pump (for hydraulic power), depending on the aircraft design.
Deployed only in emergencies, RAT works solely by air pressure and motion—does not require electrical power to function. This is often used in commercial airliners like Airbus A320, Boeing 787, and in military aircraft.
Pilots can also manually deploy the RAT using a switch in the cockpit if needed. However, manual deployment may be used in scenarios where primary systems are malfunctioning but automatic triggers haven’t activated the RAT.
The RAT ensures that critical flight instruments, flight controls, and communication systems continue to function. In fly-by-wire aircraft (e.g., Airbus), it supports flight control computers. And it allows pilots to navigate and control the aircraft safely during emergencies and make a controlled landing.
But has limitations. The RAT can only provide limited power, usually sufficient for essential systems only. It cannot sustain full aircraft operations, like cabin lighting, in-flight entertainment, or galley power.
RAT effectiveness is speed-dependent; it may produce less power at lower speeds or during descent. Deployment of the RAT adds drag, which slightly reduces fuel efficiency and speed.
However, the added drag is acceptable given the critical nature of the power it supplies during emergencies.
What the expert says
An aviation technology expert and senior industry consultant, speaking to The New Indian Express (TNIE Online) on condition of anonymity due to his organization’s confidentiality policy, explained:
"Although like a little fan that powers up the electrical and hydraulic systems giving life to flight controls, the RAT allows at least directional and altitude control," he says.
"But to remain airborne or even glide there has to be a certain quantity of airflow over the wings . But in this case that airflow stopped and it was so low that it stalled — in aviation parlance the aircraft was too low and too slow. If it had altitude he could lose some of that to gain speed, and if he had speed he could gain some altitude," he explained.
More critically, he added; "If the aircraft had been at a higher altitude—and assuming the same sequence of events—the pilot might have managed a crash landing that could have saved some lives."
A real-world example was Air Transat Flight 236 in 2001. As several earlier reports wrote, the Airbus A330 experienced fuel exhaustion over the Atlantic. The RAT deployed and provided power for flight controls and essential systems, enabling a successful emergency landing in the Azores,
The Ram Air Turbine is a vital emergency backup system that enhances the safety and reliability of modern aircraft. While rarely deployed, its presence ensures that even in catastrophic power failure scenarios, the aircraft retains enough functionality to be navigated and landed safely.