Boeing Co. faced growing pressure in Washington on Wednesday with U.S. lawmakers calling for executives to testify about two crashed 737 MAX jets even as the world's biggest plane-maker works to overcome obstacles to returning the grounded fleet to the skies.

The Senate hearing, at an unspecified date, would be the first time that a U.S. congressional committee has called Boeing executives to appear for questioning about 737 MAX passenger plane crashes in October in Indonesia and March 10 in Ethiopia.

On March 27, the same panel, the Senate Commerce subcommittee on aviation and space, also will question U.S. Federal Aviation Administration (FAA) officials. They will likely be asked why the regulator agreed to certify the MAX planes in March 2017 without requiring extensive additional training.