Boeing Co (BA.N) early on Tuesday won backing from Congress for an extension of a looming deadline imposing a new safety standard for modern cockpit alerts for two new versions of the U.S. plane maker’s best-selling 737 MAX aircraft.

The company has been heavily lobbying for months to convince lawmakers to waive the Dec. 27 deadline that affects its MAX 7 and MAX 10 airplanes which was imposed by Congress in 2020 after two fatal 737 MAX crashes killed 346 people in Indonesia and Ethiopia.

Congressional leaders attached the extension to a bill to fund U.S. government operations and to require new safety enhancements for existing MAX aircraft proposed by U.S. Senator Maria Cantwell, chair of the Senate Commerce Committee, according to the text made public early on Tuesday.

Reuters first reported the plan on Monday.