Does RAT Hold Key To Air India Probe? Turbine Had Deployed Before Crash

The Ram Air Turbine or RAT deploys automatically when there is a dual-engine failure
or total electronic or hydraulic failure.
New Delhi:
India saw one of its worst aviation disasters, in which at least 270 people were killed,
last week and new evidence indicates that both engines of the Air India Boeing
Dreamliner 787-8 may have failed or it may have suffered a total electrical or hydraulic
malfunction.
Clearer audio and video from the June 12 crash show that the Ram Air Turbine or RAT –
a small propeller-like device which deploys automatically when there is a dual-engine
failure or total electronic or hydraulic failure – was deployed on the Dreamliner, which
crashed just 32 seconds after taking off from the Ahmedabad airport.
The distinct high-pitched whine of the RAT can be clearly heard in the audio in the
absence of the roar of the aircraft’s jet engines and its deployment can also be made
out in the video, which shows the plane struggling to maintain altitude and then
beginning to descend rapidly.
The RAT uses wind speed to generate emergency power and experts say its
deployment, which happens automatically, points to three possible scenarios – both
engines of the aircraft failed, it suffered an electronic failure, or its hydraulics failed.
Veteran Indian Air Force Pilot and aviation expert Captain Ehsan Khalid said he had
suspected dual engine failure on the day of the crash itself, after the video emerged, as
the aircraft was not ‘yawing’ (turning abruptly) and it is nearly impossible for birds to hit
both engines at the same time.
“Dual engine failure was almost everybody’s guess. The lone survivor of the crash had
also said he heard a sound, which could be the deployment of the RAT; the racing of an
engine, which could have been the propeller turning and picking up speed; and he saw
red and blue lights, which could have been the emergency power connecting and the
emergency lights turning on,” he said.
“The aircraft was actively flying and it was not able to maintain its height. It was a dual
loss of power, which would obviously lead to lower speed and a loss of lift (the upward
force that opposes gravity and allows an aircraft to fly) and the plane will continue to go
down the way it did. The Ram Air Turbine deploys when there is a dual engine failure or
electrical failure or hydraulic failure,” he explained.
The former Air Force pilot said an electrical failure, in certain conditions, could have led
to the engines shutting down.
“The engines shut down at precisely the same time. If there had been even a
two-second difference, there would have been a predominant yaw to the left or the right.
The engines have shut down digitally, precisely, and at the same time, which could have
only happened due to a malfunction in the software, which was executed by a wrong
signal from the sensors, which could have come from an electrical failure,” he said.
Professor of airspace Dr Aditya Paranjape also said the evidence points to both engines
failing to provide thrust.
“Airplanes are configured to climb out with just one engine operational, it is a standard
manoeuvre known as a one engine out climb. That manoeuvre additionally requires that
the rudder be deflected in the direction of the working engine to balance out the
differential yawing movement, which we don’t see here… The loss of power is identical
on both sides of the airplane,” he emphasised.