The Boeing Co. goes to court on Wednesday to fight a subpoena to depose one of its executives in lawsuits brought over last year's Ethiopian Airlines crash involving its grounded 737 Max 8 aircraft.

Plaintiffs' lawyers, representing the families of the victims of the crash, want to know why Boeing produced certain discovery materials to Congress but not to them. They originally scheduled a Feb. 18 videotaped deposition but held off after Boeing brought a motion to quash the subpoena, insisting that plaintiffs' attorneys received the same information that Congress did, and that attorney-client privilege protected decisions relating to the production of those documents.

U.S. Magistrate Judge David Weisman of the Northern District of Illinois is set to hear the motion on Wednesday.

"Plaintiffs have issued a deposition notice that would require Boeing to produce a corporate representative to testify about Boeing's collection and production of documents for a separate proceeding—specifically, the ongoing Congressional inquiries into the 737 Max," wrote Boeing attorney Dan Webb in the Feb. 13 motion to quash. "But this deposition notice improperly seeks privileged information, for Boeing's collection and production of documents to Congress has of course been overseen and directed by counsel."

The motion included an attached declaration from Boeing Assistant General Counsel Jonathan Boatman, insisting that such information was "inextricably intertwined with not only advice and communications with counsel, but also attorney mental impressions and thought processes."

Webb, co-executive chairman at Winston & Strawn, did not respond to a request for comment.

Attorney Robert Clifford, of Chicago's Clifford Law Offices, said Boeing has not given plaintiffs the same documents that Congress received, and a corporate representative should explain why.

"We're trying to get the discovery moving here," he said.

The discovery dispute comes as Congress continues to probe the cause of the March 10 crash that killed 157 people and came about four months after 189 people perished on a Lion Air flight that also involved the Max 8 aircraft. In October, the U.S. House of Representatives Committee on Transportation and Infrastructure and the U.S. Senate Committee on Commerce, Science, and Transportation held hearings about the Max 8.

Boeing, meanwhile, has delayed reintroducing the Max 8 to the air. Last month, Boeing posted its first annual loss in two decades due to the grounding of the aircraft, which has cost nearly $19 billion.

Last year, Boeing agreed to mediate lawsuits brought over the Lion Air crash, and offered a $100 million fund to local community groups and nonprofits to assist families of the victims of both Max 8 crashes.

About 100 lawsuits brought over the Ethiopian Airlines crash are pending, with discovery just beginning.

In a Monday status report, Boeing said it had agreed to make John Hamilton, the chief engineer of the Max 8 who testified before Congress, available for a deposition on April 15 or 16, but still opposed the request for a corporate representative. The Jan. 14 subpoena included "all methods and/or procedures" Boeing used in its production of documents to Congress.

"These review and collection efforts were prepared, directed, and performed by or in conjunction with counsel," Webb wrote in Boeing's motion to quash. "Plaintiffs nevertheless seek to probe into privileged subject matter including counsel's mental impressions, strategy decisions, and thought processes."

Boeing, which said it had produced 27,000 documents to Congress, said plaintiffs' lawyers have the same materials other than those relating to the particulars of the crash investigations, which the National Transportation Safety Board prohibits it from disclosing under Annex 13 of the Convention on International Civil Aviation.

In Monday's status report, Clifford said Boeing is using the federal limitation to protect too much.

"Whether and to what extent Boeing withheld materials relevant to the design failures on the 737 Max aircraft from the Lion Air investigators is critical to the question of liability and punitive damages," he wrote in Monday's status report.