Why Air India Birmingham Flight Flashed 'Duel Engine Failure' RAT Sign —Boeing 'Explains'

New Delhi: Boeing, aeroplane manufacturing giant, has explained why Ram Air Turbine (RAT) deployment took place without a command given by the flight pilot on Air India Dreamliner 787-8 Birmingham flight before

it was about to land earlier this month on October 4. The flight AI117, which was operating from Amritsar, had landed safely.Boeing also gave out reason as to why other 787-8 Dreamliners faced a similar issue and explained the mechanism behind it after India’s aviation watch Director General of Civil Aviation (DGCA) asked Air India to meticulously repeat the RAT stowage procedure according to the Boeing Aircraft Maintenance Manual (AMM).

What is RAT Deployment?

According to aviation experts, the RAT deployment is a serious indication of aircraft malfunction as it takes place when a plane goes through a dual engine failure or total electrical failure. And if such a sign is activated, with or without pilot’s intervention, it means that flight is in serious trouble.RAT deploys automatically in the eventuality of a dual engine failure or total electric or hydraulic failure. It uses wind speed to generate emergency power.

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What Boeing told DGCA

Explaining the matter to India’s aviation watchdog, Boeing said that the flashing of RAT deployment occurred due to mechanical toggle inside the RAT Storage system which can slip out of its place after the plane had gone for maintenance. Describing the process further, the aviation giant said that the Dreamliners were put into service 14 years ago and there have been around 31 cases so far when they have witnessed uncommnanded — without Pilot’s intervention — RAT deployment or emergency trigger. Out of these 31 cases, 29 planes were installed with old RAT Stove actuators without a modified shuttle valve."Notably, 29 of these 31 events involved RAT stow actuators that lacked a modification to the shuttle valve - a component responsible for controlling pressure within the up-lock toggle mechanism. These incidents typically occurred within six months after maintenance requiring manual RAT stowing, as outlined in the Aircraft Maintenance Manual (AMM)," the official noted.The function of this modified shuttle valve is to control the pressure inside the unlock toggle mechanism and to also make sure that the RAT indiction stay locked.

What Happens to RAT in some Dreamliners During Maintenance

Boeing said that after maintenance when the RAT is stored manually, the toggle mechanism may not lock properly.And during take off, landing or during vibrations, may lead to the slipping of toggle valve resulting in RAT indication deployment unexpectedly.To minimise the risk of toggle misalignment, Boeing had introduced a design change to the shuttle valve within the RAT stow actuator."VT-ANO and 18 other Boeing 787 aircraft in the Air India fleet do not have the modified RAT shuttle valve," the official said, clarifying that there is no Service Bulletin (SB), Service Letter (SL), or Service Information Letter (SIL) available regarding the shuttle valve design improvement.

According to a senior official, out of 31 instances of uncommanded deployment of RAT in the last 14 years globally and most of the incidents typically occurred within six months of carrying out certain maintenance works.The DGCA, earlier this month, asked Air India to meticulously repeat the RAT stowage procedure according to the Boeing AMM for 16 of the airline's Dreamliners that had undergone RAT deployment in the past six months.In the case of Air India's VT-ANO aircraft, RAT maintenance was done in July 2025, after which the RAT was manually stowed.

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"A total of 16 Boeing 787 series aircraft were identified for this preventive action. Of these, RAT stowage has already been repeated for 14 aircraft, ensuring proper seating of the toggle assembly and reducing the risk of inadvertent RAT deployment due to pressure fluctuations or mechanical shocks."The remaining two aircraft are scheduled for completion of the RAT stowage task during ongoing Base maintenance activities," the official said.Considered an airline's workhorse for long-haul flights, Dreamliners took to the skies 14 years ago, and now, more than 1,100 such planes are in service.

Rat System Activated in ill-fated Air India Ahmedabad-London Flight

RAT deployment was witnessed on Air India's Dreamliner Ahmedabad–London flight that crashed and claimed 241 lives out of 242 people onboard on June 12 this year.With inputs from PTI