Families of victims of Lion Air flight 610 attend a meeting with authorities and Lion Air management in Jakarta. (Ulet Ifansasti/Getty Images)

The father of an Indonesian doctor who died in the Oct. 29 Lion Air disaster is suing Chicago-based Boeing over a technical issue that allegedly played a role in his son’s death, in what appears to be the first formal legal action implicating the jet manufacturer in a crash that killed 189 people.

The lawsuit was filed Wednesday in the Circuit Court of Cook County, Illinois, by H. Irianto, the father of Dr. Rio Nanda Pratama. Pratama had been returning to Pangkal Pinang, in the east of Indonesia, from a conference in Jakarta to attend his own wedding when the brand-new Boeing 737 MAX8 he was aboard crashed into the Java Sea. The plaintiff is seeking “all damages available under the law,” citing Illinois wrongful death statutes.

The cause of the crash has not yet been determined with certainty, with a full investigation expected to be finished later this month. But recent revelations that pilots weren’t trained on a new automated flight control feature in the 737 MAX8, which has been linked to the crash in initial statements by Indonesian authorities, have cast an unexpected spotlight on Boeing.

“What is particularly noteworthy and disturbing about this case is that the evidence that has been made public so strongly points in the direction of a defect in the design of the Boeing 737 MAX aircraft and a failure by Boeing to adequately instruct and warn its airline customers and their pilots about the changes it made to the flight control system,” Curt Miner, an attorney representing the plaintiff, said in an email.

“In recent years, when aviation accidents have occurred in foreign countries, they have typically been attributed to pilot error," he added.

Boeing spokesman Paul Bergman said “we extend our heartfelt condolences and sympathies to the families and loved ones of those on board" in response to a request for comment on the lawsuit.

If authorities conclude that a flight system failure caused the crash, it could deal a blow to Boeing’s commercial prospects at a time when it is trying to sell more passenger jets abroad. The 737 is the best-selling commercial jet in the company’s history, and the MAX8 was billed as an evolution of a tried-and-tested airplane.

A week after the crash, Boeing warned international airlines that they could experience erroneous warnings from flight-control software on its planes related to so-called Angle of Attack (AOA) sensors, which measure which direction the plane’s nose and make automatic adjustments to prevent the plane from stalling. The company also notified pilots that a manual override built into previous plane models does not work on the Max 8. The Federal Aviation Administration issued its own separate warning drawing attention to the same issue on 737 MAX 8 and 9 planes.

Pilots' representatives were caught off-guard by Boeing’s disclosure, saying they were not trained to handle or even made aware of that automated system, which can pitch the nose of a plane downward if it is fed faulty data. It was only on Nov. 7 — after disclosures from Indonesian authorities — that Boeing notified pilots of the systems' existence and added it to pilot manuals, representatives from two U.S. pilot unions said.

In the lawsuit filed Wednesday, Irianto blamed Boeing. His complaint argues that the company is guilty of negligence for designing a potentially faulty flight control system that is hard to override manually. The suit pointed to news reports stating that pilots had been insufficiently trained to handle the system.

“At no relevant time prior to the crash of Lion Air Flight 610 into the Java Sea did Boeing adequately warn Lion Air or its pilots of the unsafe condition caused by the new “auto-diving” design of the 737 MAX 8 flight system,” the suit alleged.

The outcome of Irianto’s suit will probably depend on whether the authorities determine that Boeing was at fault for the plane crash — as opposed to the regulators that signed off on system changes in the first place, or pilots who failed to steer the plane to safety.

Pilots' associations have also criticized the Federal Aviation Administration and the National Transportation Safety Board, regulatory entities that would have signed off on changes to flight control systems, for not spotting the issue sooner.

“While the FAA and NTSB have been actively assisting in this investigation, the lack of critical safety information being provided to the air carriers and front-line operators is concerning,” Air Line Pilots Association president Tim Canoll wrote in a recent letter to regulators.