Mumbai/ New Delhi, Oct 5 (PTI) In a major incident involving an Air India plane, Ram Air Turbine, which is usually used in case of engine failures, got deployed without any command from a Boeing 787-8 Dreamliner aircraft a few minutes before landing at the Birmingham airport on Saturday, according to officials.

Aviation watchdog DGCA is probing the incident involving aircraft VT-ANO operating the flight AI117 from Amritsar to Birmingham on October 4.

The plane landed safely, the officials said on Sunday.

Generally, RAT gets deployed automatically in the eventuality of a dual engine failure or electrical/electronic or hydraulic failure, among others.

It uses wind speed to generate emergency power.

The incident has also raised safety concerns, with the Federation of Indian Pilots (FIP) urging DGCA to carry out thorough checks and investigate the electrical system of all Boeing 787 aircraft in the country.

The deployment of RAT also assumes significance against the backdrop of the crash of an Air India Dreamliner that killed 260 people on June 12.

After the fatal accident also, concerns were raised in some quarters about the safety of Dreamliners and some reports had suggested that RAT was deployed prior to the crash, which happened soon after take-off.

In a statement on Sunday, an Air India spokesperson said the operating crew of flight AI117 from Amritsar to Birmingham on October 4 detected deployment of RAT of the aircraft during its final approach.

"All electrical and hydraulic parameters were found normal, and the aircraft performed a safe landing at Birmingham," the airline said but did not share specific details, including the number of people who were onboard the plane.

A senior DGCA official told PTI that RAT got deployed during landing of the plane at 400 feet but the pilot did not report any related abnormality.

The maintenance actions for uncommanded RAT deployment recommended by Boeing have been carried out and no discrepancy were observed, the official said and added that the aircraft is being released for service.

The official also said the Directorate General of Civil Aviation (DGCA) will carry out a detailed investigation into the incident.

There was no comment from Boeing on the latest incident involving the Air India plane.

In a letter to the DGCA, pilots' grouping FIP on Sunday said the RAT was deployed automatically from the Air India's Dreamliner aircraft at around 500 feet on approach to Birmingham.

"The Aircraft Health Monitoring (AHM) has picked up a fault of the Bus Power Control Unit (BPCU) which may have caused the auto deployment of RAT," the pilots' grouping said.

BPCU manages an aircraft's electrical power system.

"There have been numerous incidents on B787 aircraft. We have strongly taken up with the Civil Aviation Ministry and Aircraft Accident Investigation Bureau (AAIB) to thoroughly check the electrical system of all B787 aircraft in the country.

"After the Air India 171 crash, the FIP has been constantly insisting on thorough check up of the electrical system of B-787 aircraft in the country. Subsequent to the crash, DGCA checked only the fuel control switches of B-787 in Air India (fleet)," the pilots' body said in the letter.

On June 12, Air India's Boeing 787-8 aircraft operating flight AI 171 en route to London Gatwick crashed into a medical hostel complex soon after take-off from Ahmedabad, killing 260 people, including 241 persons who were onboard the plane.

Engine or hydraulic/electrical failure, software malfunction and possible pilot error are among the several probable causes being looked into for the crash.

Aircraft Accident Investigation Bureau (AAIB) is probing the crash and in its preliminary report, released on July 12, said engine fuel control switches of the ill-fated Boeing 787-8 plane were cut off seconds after lift-off, with one of the pilots asking the other why did he cut off, and the latter responding saying he did not do so.

"It is pertinent to note that incident in another pointer towards the Air India crash of B-787 aircraft. Thus, in the interest of air safety FIP insists that DGCA must thoroughly check and investigate the electrical system of B-787 aircraft in the country," the Federation said in the letter.

Currently, there are 33 Boeing 787s, also known as Dreamliners, with Air India. IndiGo also operates the aircraft that has been taken on lease. PTI IAS RAM HVA