The families of four passengers who died on an Air India jet that crashed in June have filed a lawsuit in the US against planemaker Boeing and aircraft parts maker Honeywell, accusing the companies of negligence.

The lawsuit filed Tuesday, and seen by the BBC, stated that faulty fuel switches caused the accident and accused the companies of doing nothing despite being aware of the risks associated with the aircraft's design.

Air India Flight 171, a Boeing 787 bound for London Gatwick, crashed shortly after takeoff from Ahmedabad, killing 260 people.

Fuel switches have become a focus for investigators after a preliminary inquiry found that fuel to the engines was cut off moments after the plane left the ground.

The US Federal Aviation Administration (FAA) has stated earlier that fuel control switches in Boeing aeroplanes are safe.

The BBC has contacted Boeing and Honeywell for a response, but the US plane manufacturer did not comment on the case and referred to India's Aircraft Accident Investigation Bureau's (AAIB) preliminary findings on the crash.

The lawsuit claims both firms were aware of the risk associated with the 787 Dreamliner and had failed to provide necessary inspections or parts for fuel switch repairs. According to the families, the companies sat idly behind a non-mandatory FAA advisory, resulting in myriads of avoidable fatalities.

A more detailed report of the crash is expected in 2026.