Boeing has withdrawn a request for the Federal Aviation Administration to grant a safety waiver for the 737 Max 7 after the manufacturer reported an issue with the Max’s anti-ice system last year.

“We have informed the FAA that we are withdrawing our request for a time-limited exemption relating to the engine inlet deicing system on the 737-7,” Boeing said Monday in a statement. “While we are confident that the proposed time-limited exemption for that system follows established FAA processes to ensure safe operation, we will instead incorporate an engineering solution that will be completed during the certification process.”

The withdrawal follows pressure from Democratic Sen. Tammy Duckworth of Illinois, chair of the Senate Subcommittee on Aviation Safety, who last week sent a letter to the FAA demanding it reject Boeing’s request. 

“While Boeing never should have sought this exemption to put another new aircraft with a known safety defect into service in the first place, I’m both relieved and appreciative that they are putting the flying public’s safety first by withdrawing this petition,” Duckworth said Monday. “I hope this decision marks the beginning of a turnaround in Boeing’s safety culture moving forward and I encourage the company to put its full focus into fixing the known safety flaw on the MAX 7 and other MAX aircraft that could lead to catastrophic consequences for passengers and crew.”

The FAA in August 2023 issued an Airworthiness Directive, a regulation designed to fix an issue with a plane, that “was prompted by a report indicating that use of engine anti-ice (EAI) in dry air for more than five minutes during certain environmental and operational conditions can cause overheating of the engine inlet inner barrel beyond the material design limit, resulting in failure of the engine inlet inner barrel and severe engine inlet cowl damage.”

The 737 Max 7, the smallest of the four 737 Max variants, is currently uncertified, but the issue also exists on 737 Max 8 and Max 9 aircraft already flying.  

The FAA approved Boeing’s guidance to mitigate the problem on the existing fleet of Max aircraft while Boeing engineered a fix by May of 2026. The FAA told airlines that pilots should limit the use of the anti-ice system to less than five minutes until Boeing’s fix was available.

While the issue has never occurred in-flight, Boeing determined it was theoretically possible under specific weather conditions, and in a worst-case scenario, could result in components breaking off. 

The now-withdrawn limited-time exemption would have allowed Boeing to deliver the Max 7 to airlines once certified. The company has more than 4,300 orders for the 737 Max family of aircraft.  

Democratic Sen. Maria Cantwell, of Washington, who serves as Commerce Committee chair, called Boeing’s withdrawal “good news,” and said she hopes “this means they can quickly develop a compliant design across other MAX planes.”  

In a letter sent late Wednesday to FAA Administrator Michael Whitaker and obtained by CBS News, Duckworth wrote, “Boeing forfeited the benefit of the doubt long ago when it comes to trusting its promises about the safety of 737 MAX, and the FAA must reject its brazen request to cut corners in rushing yet another 737 MAX variant into service.”

In an interview with CBS News, Duckworth said the waiver request was an “attempt to put profits over the safety of the flying public. They want a special permission to be allowed to continue to use this component with a known problem on an aircraft that has yet to be certified and allow it to be put into service. You cannot have a new baseline where we’re going to certify aircraft that are not safe to fly.”

Boeing’s 737 Max line has been at the center of multiple tragedies, scandals and close calls since being put into service. 

Two 737 Max 8 crashes, one in 2018 and one in 2019, led to the entire fleet being grounded. Investigations determined those crashes, which killed a total of 346 people, were the result of false readings causing an automated system on the planes to pitch the noses of the aircrafts down. The entire Max fleet was grounded for months following the second crash.

Earlier this month, the door panel of a 737 Max 9 blew off during an Alaska Airlines flight. That Max 9 fleet was grounded following that incident, but has returned to service in the last week.