FAA let American Airlines fly planes that shouldn't have been considered airworthy after maintenance oversight lapses, DoT investigation finds

• A DOT report says the FAA "lacks effective oversight" of American Airlines' maintenance safety programs.

The Federal Aviation Administration "lacks effective oversight" of American Airlines' maintenance safety programs, the US Department of Transportation reported on Friday, and as a result the airline flew aircraft that should not have been considered airworthy.

The DOT Inspector General's office published a report that said the FAA does not effectively ensure American is taking corrective actions to address the root cause of maintenance issues on its aircraft or properly mitigate risks. When a plane malfunctions, the company is required to assess the risk of the issue, determine its root cause, and fix it, according to safety experts.

According to the DOT, the FAA has not ensured American is adequately assessing its broken aircraft and implementing the correct fixes, meaning the airline is not addressing the root problem that caused the malfunction. When this happens, the company leaves a potential safety concern unchecked.

The DOT said the reason for the lack of oversight was because FAA inspectors are not sufficiently trained, and some are not trained at all, in root-cause analysis or risk assessment. This caused them to accept lackluster root causes in 171 of the 185, or 92%, of maintenance issues reviewed from 2016 to 2020. In addition, FAA inspectors were closing out issues before American corrected them, so the agency could not ensure the airline actually took the safety action it said it would, potentially meaning the aircraft shouldn't fly at all.

Safety inspectors were also reportedly not trained to ensure American's safety management system is effective, which is a required program used at airlines to identify and address safety concerns before an event actually occurs. Because inspectors were not properly trained, American did not fix the issue.

The report documents several maintenance incidents at American, including an aircraft that flew for 877 days with a broken emergency slide. According to Reuters, American said it reported the slide issue as soon as it was discovered in line with its maintenance program procedures, but the FAA said that because the problem was not given a high enough risk assessment, it did not get the attention it should have, allowing the plane to fly with insufficient safety equipment.

Another case revealed American failed to risk assess an engine that had incorrectly installed struts, which secure the engine in place. Without the risk assessment prompting a fix of the problem, which is how safety systems at airlines are intended to work, the plane flew 1,002 flights when it shouldn't have been flying at all, according to the DOT.

American Airlines has gone almost 20 years without a fatal accident, but the insufficient oversight from the FAA is concerning, according to the DOT. In its report, the DOT made recommendations to improve the oversight, including providing better training to inspectors and implementing procedures that ensure corrective actions are taken before cases are closed.

American defended its safety approach in a statement to Insider but said it welcomes the DOT's assessment.

"Nothing is more important than the safety of our customers and team members," American told Insider. "It guides every decision we make and action we take, and we're proud of our strong safety culture and safety record."

"This has always been our approach: Open, transparent communication and collaboration with our regulators and immediate action to remedy issues and ensure the continued safety of our airline and the industry," the carrier said. "We plan to work with the FAA to ensure we take positive action and continuously refine and improve our safety controls."