Aerospace giant Boeing and fuel control switch maker Honeywell have been sued by the families of four passengers who died in the Air India crash in Ahmedabad on June 12.

In a lawsuit filed in a Delaware court, the plaintiffs have alleged that the crash resulted from faulty fuel switches that could be turned off inadvertently, shutting down fuel supply immediately after takeoff.

The lawsuit refers to a 2018 Special Airworthiness Information Bulletin (SAIB) issued by the U.S. Federal Aviation Administration (FAA) that suggested, though it was not required, that operators of various Boeing models, including the 787, check the locking mechanism of the fuel cutoff switches to make sure it couldn't be unintentionally altered.

London-bound AI-171, a Boeing 787-8 Dreamliner, burst into a fireball 32 seconds after take-off from Ahmedabad, killing all but one of the 242 people on board and several others on the ground.

The crash, marking the first hull loss for a Boeing Dreamliner, prompted urgent safety checks by India’s aviation regulator. The Directorate General of Civil Aviation (DGCA) ordered Air India to undertake immediate technical inspections of all Boeing 787-8 and 787-9 aircraft fitted with GE Aerospace’s GEnx engines. It also intensified surveillance of maintenance protocols and airworthiness procedures for all wide-body aircraft operating in India, in addition to a special audit to strengthen aviation safety.

The DGCA also issued an advisory to Indian airlines operating specific Boeing aircraft models, instructing them to conduct mandatory inspections of the fuel control switch locking mechanism.

Preliminary findings from India’s Aircraft Accident Investigation Bureau (AAIB) suggested that both engines stopped receiving fuel because the switches controlling fuel flow had moved into the “cutoff” position early in the flight.