New York, New York - Proceedings opened Monday in the latest trial over the fatal Boeing 737 MAX crashes, with relatives of an Irish-born United Nations employee looking to hold the plane manufacturer accountable.

Michael "Mick" Ryan, an engineer with the UN World Food Programme who had worked during the Ebola crisis in Liberia and with Rohingya refugees, died in the ill-fated March 2019 crash on Ethiopian Airlines.

A US court will hear claims from Ryan's survivors in order to determine damages, in one of the final civil claims stemming from two MAX calamities in 2018 and 2019 that together claimed 346 lives.

The 737 MAX, which had been delivered to Ethiopian Airlines months earlier, crashed moments after departing Addis Ababa for Kenya.

"He was a humanitarian in every sense of the word," Ryan's widow Naoise Ryan said of her late husband, upon accepting an award from the Irish Red Cross in 2020.

"From the time we met in college, he really believed he could make a difference in the world, and he had the skills and talent to make that happen."

A UN memorial page to Ryan, who was 39 at the time of the crash, recognized his support for vulnerable populations in Afghanistan, Sri Lanka, Nepal, Ethiopia, and, most recently, Bangladesh, where Ryan oversaw the building of shelters and evacuations that "saved tens of thousands of Rohingya refugees from the threat of landslides and floods."

Plaintiffs in the suit include Naoise Ryan, daughter Saorlaith, and son MacDara, who were three years and six months old at the time of the accident.

A Chicago jury will hear a trial expected to take about 12 days, with testimony from Ryan's family and colleagues.

Naoise Ryan's attorney Steven Marks said she would not accept a settlement from Boeing.

"Our client is committed to seeking accountability and justice from a jury and not accepting money from Boeing directly," Marks told AFP.

Naoise Ryan rejected Boeing's voluntary payments to victims as "blood money" and redirected her allotment of $1.65 million to an aviation safety foundation.

Boeing has apologized for the crashes and acknowledged that anti-stall software was implicated in both accidents. The company has settled the vast majority of claims with agreements not made public.

In May, a Chicago jury awarded $49.5 million in damages to the family of Samya Stumo, a 24-year-old American who was killed on the same Ethiopian Airlines flight.

In that trial, attorneys for the Stumo family ripped Boeing as "negligent" in the calamity while relatives described themselves as devastated by loss.

Stumo was killed en route to Kenya for her first assignment with ThinkWell, a public health NGO that aimed to increase access to health care in Africa and Asia.