Mumbai: The Directorate General of Civil Aviation (DGCA) has directed Air India to reinspect the Ram Air Turbine (RAT) on all aircraft whose power conditioning modules (PCMs) was replaced recently.
The aviation regulator has also sought a “comprehensive report” from US aircraft-maker Boeing on the preventive measures to be implemented with respect to the un-commanded Ram Air Turbine (RAT) deployment incident in an Amritsar-Birmingham flight on October 4.
This comes after Air India said that the RAT deployment was not due to system fault or pilot action.
There were two back-to-back incidents involving Air India Boeing 787 aircraft recently, following which the Federation of Indian Pilots (FIP) wrote to the civil aviation minister, urging the government to ground Air India’s entire 787 fleet, besides a special audit of the airline.
The RAT got deployed on the Amritsar-Birmingham flight just before it landed. Barely five days later, AI-154 from Vienna to Delhi, operated by a Boeing 787 aircraft, was diverted to Dubai, due to the “sudden failure of autopilot system, triggering a series of technical malfunctions”.
Air India had categorically denied “any assertion that there was an electrical failure” in the Boeing 787 aircraft that was diverted to Dubai on October 9.
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 till the engines can be reignited.
“Air India has been advised to reinspect the RAT for stowage for all the aircraft, whose PCM module was replaced in the recent past,” a senior DGCA official has been quoted as saying by Deccan Herald.
PCM is a crucial electrical component that converts, regulates and distributes electric power from the aircraft’s power generation system to various onboard systems and equipment.
During landing at 400 feet, the RAT unlock message came, and it got deployed. The pilot did not report any related abnormality, and the aircraft landed safely, the DGCA official said.
Following this, Boeing-recommended maintenance actions for un-commanded RAT deployment were carried out, and no discrepancy was observed, the official said, adding that accordingly, the aircraft was released for service and brought back to Delhi on October 5.
“Boeing has been requested to provide a comprehensive report outlining the preventive measures to be implemented in respect of the un-commanded RAT deployment incident,” the official said.
Detailed information regarding similar un-commanded RAT deployments that occurred globally on Boeing 787 series aircraft, as mentioned in the Boeing 787 Fleet team Digest, has also been sought by DGCA.
Boeing has also been asked to provide any service difficulty report received from aircraft operators worldwide after the change of the PCM module,” the official added.
Though Air India cited “technical issue” due to which its Vienna-Delhi flight was diverted to Dubai, the FIP, in its letter to the civil aviation minister, revealed that the Boeing 787 aircraft “experienced failures across critical systems, which included Autopilots, ILS (instrument landing system), flight directors (FDs) and flight control system degradation with no autoland capability”.
“The pilots could not engage the autopilots due to electrical malfunctions; thus, pilots were constrained to fly manually at night and divert to Dubai. Moreover, the FDs were not available with degraded flight control systems. The aircraft landed safely at Dubai,” the FIP had said in the letter, while demanding the grounding of the entire B787 fleet and a special DGCA audit of Air India.
In one of the worst aircraft accidents in India, 260 people, including 241 passengers, died when Air India’s Boeing 787-8 aircraft operating flight AI171 to London Gatwick crashed soon after take-off from Ahmedabad on June 12.