A measure to give Boeing Co. a reprieve by allowing certification work to proceed on two new 737 Max models is unlikely to be added to a must-pass defense bill in Congress, dealing a temporary setback to the company. 

The provision, which would give Boeing more time to certify the Max 7 and Max 10 models without having to add costly upgrades to their safety alerting systems, is opposed by some lawmakers and family members of crash victims. 

There’s no indication the provision will be in the annual defense authorization bill, Washington Democrat Adam Smith, the chair of the House Armed Services Committee, said in an interview. Smith is one of the top negotiators on the defense measure. 

A Senate aide also said the Boeing legislation isn’t going to make it into the bill. The aide asked not to be named because lawmakers are still negotiating the final defense package. Those negotiations are fluid and the text could still change.

Supporters including Maria Cantwell, chairwoman of the Senate Commerce, Science, and Transportation Committee, had been trying to attach compromise language to a bill setting Defense Department policy. It’s still possible they could get it across the finish line this year, including as part of a year-end government spending bill, but time is running short before Congress adjourns. 

Congress’ omission would be a blow to Boeing, which is working with the Federal Aviation Administration to finalize certification of the two Max models. The FAA has said a law passed in 2020 requires it to halt work on the jets after the Dec. 27 deadline until Boeing can extensively redesign their safety alerting systems.