The acting head of the US Federal Aviation Administration says he has no specific timetable to approve Boeing’s 737 Max for flight following two fatal crashes that prompted the plane’s worldwide grounding.

The FAA was to meet more than 30 international air regulators, including China, the European Union, Brazil and Canada, on Thursday to discuss a software fix and new pilot training developed to ensure the jets are safe.

“It’s a constant give and take until it is exactly right,” Deputy FAA Administrator Dan Elwell said ahead of the talks.

“It’s taking as long as it takes to be right.”

The announcement came as a French woman whose husband died in the Ethiopian Airlines Boeing Max crash has reportedly filed a lawsuit against the plane manufacturer, seeking at least $US276 million ($401 million) in damages.

Lawyers for Nadege Dubois-Seex, whose complaint was filed on Monday, allege Boeing failed to properly inform pilots about the risks of faulty software that was meant to prevent the 737 Max from stalling.

Ms Dubois-Seex’s husband, Jonathan Seex, was a Swedish and Kenyan citizen and chief executive of the Tamarind Group of Companies.

Dozens of families have sued Boeing over the Lion Air crash in Indonesia in October and there are already other lawsuits following the Ethiopian crash which prompted the plane’s global grounding in March.

In all, 346 people died in the two crashes.

Boeing said last week it had completed the software fix for the Max planes. US airlines reportedly want them flying again in time for the northern hemisphere’s summer.

But Mr Elwell would not be drawn on a date.

“If you said October I wouldn’t even say that, only because we haven’t finished determining exactly what the training requirements will be,” he said.

Mr Elwell said he planned to share the FAA’s “safety analysis that will form the basis for our return to service decision process” on Thursday.

But he said the agency was still waiting for Boeing to formally submit the software upgrade for approval, and emphasised the FAA had not decided on the revised training requirements, including whether to require simulator training.

Global airlines that had rushed to buy the fuel-efficient, longer-range aircraft have since cancelled flights and scrambled to cover routes.

Mr Elwell rejected any idea he was trying to win consensus with international regulators over the path to re-approving the MAX at the meeting.

Foreign regulators have signaled disagreements about measures to end the grounding. Canadian Transport Minister Marc Garneau has called for pilots to receive simulator training for the Max, rather than just computer courses.

Canada and Europe said on Wednesday they would bring back the grounded aircraft on their own terms if their specific concerns were not addressed.

-with agencies