New Delhi: Air India replaced the Throttle Control Module (TCM) – that includes the fuel control switch – of the Boeing 787-8 aircraft that crashed in Ahmedabad on June 12 twice — once in 2019 and again in 2023 — following a directive from the aircraft manufacturer.
These replacements had nothing to do with any issue with the fuel control switch, the preliminary report of the Aircraft Accident Investigation Bureau (AAIB) has stated. These switches have become a focal point in the probe after both were found to be in the Cut-Off position shortly after the aircraft took off for London with 242 people.
According to officials, the he replacements of the TCM was carried out in compliance with a revised Maintenance Planning Document (MPD) issued by Boeing in 2019. The MPD directed all Dreamliner operators to replace the TCM every 24,000 flight hours. Air India replaced the TCM as per the guidelines twice.
The AAIB has said that the TCM replacements were not related to any defect in the fuel control switches. It noted that Air India had not reported any issues with the switches since 2023.
The AAIB report also highlights a 2018 bulletin from the US Federal Aviation Administration (FAA) that warned about the possibility of the locking feature on fuel control switches getting disengaged, though the concern was not classified as a safety issue requiring an Airworthiness Directive.
“As per the information from Air India, the suggested inspections were not carried out as the SAIB (Special Airworthiness Information Bulletin) was advisory and not mandatory,” the report stated.
Air India issued a statement on Monday in which it said: “We continue to fully cooperate with the AAIB and other authorities as their investigation progresses. Given the active nature of the investigation, we are unable to comment on specific details and refer all such enquiries to the AAIB.”
Boeing had also said that it is supporting the probe. “We will defer to the AAIB to provide information about AI171, in adherence with the UN International Civil Aviation Organization protocol known as Annex 13,” a Boeing spokesperson had said.
