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Aviation safety regulator Directorate General of Civil Aviation (DGCA) will investigate the unexpected and uncommanded deployment of the ram air turbine (RAT) — a last-resort emergency power system — of an Air India Boeing 787-8 aircraft on Saturday, said sources in the know. Meanwhile, pilot grouping Federation of Indian Pilots (FIP) has urged the DGCA to inspect the electrical systems of all Boeing 787 aircraft operating in India, arguing that the RAT deployment points at electrical system issues with the Boeing 787s, one of which crashed in Ahmedabad in June.
The RAT of the Boeing 787, operating flight AI117 from Amritsar to Birmingham, was deployed shortly before it landed safely at Birmingham airport on Saturday, even as all electrical and hydraulic parameters were found to be normal, according to the airline. The plane was grounded for checks in Birmingham.
According to sources in direct knowledge of the matter, the RAT was deployed when the aircraft was at the altitude of just 400 feet, but the pilot did not report any related abnormality, and the plane landed safely. Maintenance actions for uncommanded RAT deployment, as advised by Boeing, have been carried out and no discrepancies were found. The aircraft is being released for operations, but the DGCA will be holding a detailed investigation into the bizarre incident.
In modern aircraft, the RAT–a small wind-operated turbine deploys automatically during grave emergencies involving total electrical failure or a debilitating hydraulic failure. Pilots can also deploy it manually. An accidental automatic RAT deployment without an emergency situation is an extremely unusual occurrence.
The system was one of the points of focus in the days following the crash of an Air India Boeing 787-8 aircraft in Ahmedabad on June 12, which killed 260 people. The doomed aircraft’s RAT was deployed moments after liftoff, as the engine fuel control switches transitioned from ‘RUN’ to ‘CUTOFF’, which shut down both plane engines, according to the preliminary probe report. A detailed technical investigation into the crash is underway and the final investigation report is expected in a few months.
Pilot association FIP said that an electrical fault could have led to the deployment of the RAT on AI117, demanding that the regulator check electrical systems on all Boeing 787s. It added that this incident could also be a pointer to the Ahmedabad crash, suggesting that an electrical fault or failure could might have contributed to the disaster. It noted that while the DGCA did check the fuel control switches of all Boeing 787s in the country after the preliminary probe report was released, electrical system checks were not mandated.
“After the Air India-171 crash, the FIP has been constantly insisting on thorough check up of the electrical system of B-787 a/c (aircraft) in the country…Since the time B-787 has been flying there have been numerous incidents on B-787 a/c. We have strongly taken up with MOCA (Ministry of Civil Aviation) and AAIB (Aircraft Accident Investigation Bureau) to thoroughly check the electrical system of all B-787 a/c in the country,” the FIP said.
“It is pertinent to note that incident in another pointer towards the AI crash of B-787 a/c. Thus, in the interest of Air Safety FIP insists that DGCA must thoroughly check and investigate the electrical system of B-787 a/c in the country,” the pilot association added.
