The Federal Aviation Administration (FAA) found a series of issues at Boeing and one of its principal suppliers, Spirit AeroSystems, the New York Times reported Monday.

The recent six-week investigation started after a large window ejected in January, revealing many quality issues. The audit found that Boeing and Spirit didn’t meet necessary quality standards often, according to the New York Times. The FAA found that Boeing and Spirit AeroSystems did not comply with essential quality-control standards on multiple occasions.

Boeing passed only 56 of 89 product audits, failing 33 audits with 97 noncompliance instances noted. Spirit AeroSystems underwent 13 audits, failing to meet the standard in seven instances, the outlet reported.

Breaking News: Boeing failed 33 of 89 audits during an FAA examination of the company’s 737 Max manufacturing process.https://t.co/mwCBYZOvJK

— The New York Times (@nytimes) March 12, 2024

The FAA’s report gives detailed insights into issues with the manufacturing process. During the inspection, the safety agency noticed Spirit mechanics using a hotel key card to inspect a door seal, a method not specified in their official instructions, the New York Times reported. Additionally, the FAA observed mechanics applying liquid soap as a makeshift lubricant during assembly, later cleaning the seal with damp cheesecloth. (RELATED: Video Captures Moment Plane Tire Detaches During Takeoff, Flight Forced To Reroute)

In response to the audit, both Boeing and Spirit AeroSystems are under pressure to overhaul their quality control practices. The FAA reportedly gave Boeing 90 days to formulate a plan for improvements, and Dave Calhoun, Boeing’s CEO, acknowledged the need for corrective action, partly driven by the audit’s findings.

Meanwhile, Spirit AeroSystems is reportedly committed to addressing the identified issues and is working with Boeing to enhance safety and quality programs.

“Meanwhile, we continue multiple efforts undertaken to improve our safety and quality programs,” Spirit spokesman Joe Buccino said in a statement, the New York Times reported. “These improvements focus on human factors and other steps to minimize nonconformities.”

These issues come at a pivotal time, as Boeing has reportedly announced discussions to acquire Spirit AeroSystems, a company that became independent in 2005. The current investigations by the FAA, the National Transportation Safety Board’s look into an incident with Alaska Airlines and a criminal investigation by the Justice Department, show the significant impact of the audit’s results on Boeing’s future manufacturing and safety, according to the New York Times.