Mumbai, Sep 18 (PTI) Families of four passengers who died in the Air India plane crash in June this year have filed a product defect and negligence lawsuit in a US court against US aircraft maker Boeing and aircraft parts maker Honeywell International alleging that a faulty fuel cutoff switch led to the crash, according to a statement.

The lawsuit has compensatory and punitive damages against the defendants for the wrongful deaths of four passengers on flight 171, US-based law firm The Lanier Law Firm said in a statement.

In one of the worst aviation disasters in India's history, 260 people, including 241 passengers, died after the Tata Group-owned Air India's Boeing 787-8 aircraft operating flight AI171 to London Gatwick crashed soon after taking off from Ahmedabad on June 12.

According to the lawsuit, filed in Delaware Superior Court by The Lanier Law Firm, flight data indicates that an Air India pilot accidentally shut off fuel to Boeing 787-8 Dreamliner's engines, causing a complete loss of thrust necessary to complete the takeoff.

The fuel cutoff switch, manufactured by Honeywell and installed by Boeing, is designed with a locking mechanism to prevent unintended cutoff of fuel supply to the engines mid-flight.

India's nodal aircraft investigation agency, Aircraft Accident Investigation Bureau (AAIB), which is probing one of the country's deadliest air disasters in more than three decades, had in its preliminary report said fuel switches to engines of the aircraft were cut off within a gap of 1 second immediately after takeoff and caused confusion in the cockpit before the plane crashed into a building.

"In the cockpit voice recording, one of the pilots is heard asking the other why did he cut off (the switch). The other pilot responded that he did not do so," it had said.

But the lawsuit says these switches are installed in a "high traffic" location immediately behind and adjacent to the thrust levers that pilots continuously manipulate during takeoff.

"In addition, documents show that both Honeywell and Boeing knew the locking mechanism could easily be turned off inadvertently or could be missing altogether," it said.

That assertion is supported by a 2018 Federal Aviation Administration report confirming that Boeing and Honeywell were aware that switches were being delivered on the aircraft with the locking mechanism disengaged, allowing for "unintended" fuel cutoff mid-flight, the law firm said.

"However, there is no evidence that the companies alerted Air India or other customers that the switches must be inspected and repaired for passenger safety and did not ship replacement switches to those airlines for installation," it said.

It may also be noted that perturbed with the preliminary findings of the AAIB inquiry into the Ahmedabad plane crash, Pushkaraj Sabharwal, father of Captain Sumeet Sabharwal who was one of the pilots of the ill-fated Air India Dreamliner, has demanded a 'formal investigation' by the central government.

In a letter to the civil aviation secretary and AAIB Director General, 91-year-old Pushkaraj said selective leaks about the accident have led to speculation that Sumeet (56) was under tremendous psychological pressure and therefore was contemplating dying by suicide.

"These innuendos have very adversely affected my health and mental setup and the reputation of Captain Sumeet Sabharwal. They tarnish Captain Sabharwal's reputation, which is a fundamental right guaranteed to a citizen of India under Article 21 of the Constitution of India," the letter, dated August 29, said.

"It is shocking that Honeywell and Boeing both knew of this danger and did absolutely nothing to prevent the inevitable catastrophe that occurred on June 12," Benjamin Major of The Lanier Law Firm, co-counsel for the families, said in the statement.

"This defect is comparable to an auto manufacturer putting an unprotected emergency brake control next to a radio volume knob in your car. And unlike a car, restarting jet engines takes minutes, not seconds. Once these engines shut down, that plane basically became a 250,000-pound lawn dart," he added.

According to the lawsuit," both switches on the Flight 171 aircraft suddenly and inadvertently moved from the "RUN" to the "CUTOFF" position after just three seconds of takeoff, completely cutting fuel supply to both engines.

"A cockpit voice recorder captured a brief exchange between the pilots, indicating that neither intended to shut off fuel to the aircraft. Despite the pilots' attempts to restore engine power, there was insufficient time for the engines to restart and provide adequate thrust to prevent the crash," according to the law firm. PTI IAS TRB TRB