India’s Directorate General of Civil Aviation (DGCA), the nation’s primary aviation safety regulator, has issued a directive to Air India, instructing the airline to re-examine the stowage of the Ram Air Turbine (RAT) on all aircraft where the power conditioning module (PCM) has recently been replaced. The RAT serves as a crucial emergency power source for aircraft.
Simultaneously, the DGCA has formally requested a “comprehensive report” from the American aircraft manufacturer, Boeing. This report is expected to outline the specific preventive measures Boeing plans to implement to address incidents of the uncommanded deployment of the Ram Air Turbine.
This urgent action by the DGCA stems from two consecutive and alarming incidents involving Air India’s Boeing 787 Dreamliner aircraft. These events prompted the Federation of Indian Pilots (FIP) to send a letter to the Civil Aviation Minister, calling for the immediate grounding of Air India’s entire B787 fleet and a specialized safety audit of the airline.
The first incident occurred on October 4, when the RAT unexpectedly deployed on Air India flight AI-117, operating from Amritsar to Birmingham, just before landing. The second, on October 9, saw flight AI-154 from Vienna to Delhi, another Boeing 787 (registration VT-ANO), diverted to Dubai. This diversion was reportedly due to a “sudden failure of the autopilot system,” which subsequently triggered a cascade of technical malfunctions.
The Ram Air Turbine is engineered to deploy automatically in the rare event of a dual engine failure or a complete electrical or hydraulic system breakdown, utilizing wind speed to generate essential emergency power.
A senior DGCA official confirmed the directive, stating, “Air India has been advised to reinspect the RAT for stowage for all the aircraft, whose PCM module was replaced in the recent past,” adding that “further investigation is in progress.”
The Power Conditioning Module (PCM) is a critical electrical component vital for converting, regulating, and distributing electrical power from the aircraft’s primary generation system to various onboard systems and equipment.
It’s important to note that Air India has explicitly denied “any assertion that there was an electrical failure” concerning the Boeing 787 aircraft that was diverted to Dubai on October 9.
The DGCA has also instructed Air India to meticulously “review the work package of ‘D’ Check” — a significant, comprehensive maintenance overhaul — to identify any potential discrepancies related to the PCM module change.
Regarding the October 4 incident, the DGCA official explained that during the landing approach at 400 feet, an “RAT unlock” message appeared, followed by its deployment. Crucially, the pilot reported no other related abnormalities, and the aircraft landed safely.
Following this event, Boeing’s recommended maintenance actions for uncommanded RAT deployment were carried out, and no discrepancies were observed. Consequently, the aircraft was cleared for service and returned to Delhi on October 5.
The DGCA official further emphasized, “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.”
Additionally, the aviation regulator has sought detailed information from Boeing regarding similar uncommanded RAT deployments that have occurred globally on Boeing 787 series aircraft, as documented in the Boeing 787 Fleet Team Digest.
Boeing has also been asked to provide any service difficulty reports received from aircraft operators worldwide following the replacement of the PCM module, the official added.
While Air India cited a “technical issue” for the diversion of its Vienna-Delhi flight to Dubai, the FIP’s letter to the Civil Aviation Minister presented a more alarming account. It stated that the Boeing 787 experienced “failures across critical systems,” including the autopilots, Instrument Landing System (ILS), flight directors (FDs), and a degradation of the flight control system, which resulted in a complete loss of autoland capability.
The FIP’s letter elaborated that “pilots were constrained to fly manually at night and divert to Dubai” because they “could not engage the autopilots due to electrical malfunctions,” and the FDs were also unavailable with compromised flight control systems. Despite these severe operational challenges, the aircraft managed to land safely in Dubai. The FIP concluded its letter by demanding the grounding of Air India’s entire B787 fleet and a special audit by the DGCA.
It is also a grim reminder that India experienced one of its most tragic aviation accidents when an Air India Boeing 787-8, operating flight AI171 to London Gatwick, crashed shortly after takeoff from Ahmedabad on June 12, resulting in the deaths of 260 people, including 241 passengers.