DALLAS (NEWSnet/AP) — The federal government is fining American Airlines $4.1 million for dozens of instances in which passengers were kept aboard planes without a chance to exit during long ground delays.

U.S. Department of Transportation said Monday it is the largest such fine against an airline since rules for ground delays took effect about a decade ago.

American owes half the fine within the next 30 days. The department gave the airline credit for the other half, just over $2 million, for compensation it paid to delayed passengers, according to a consent order that settled the case.

The department said its investigation revealed that from 2018 through 2021, American kept 43 domestic flights stuck on the ground for at least three hours without giving passengers, 5,821 in all, the chance to deplane. There are exceptions in which airlines are allowed to relax the rules, including for safety and security reasons, but DOT said none of those were factors in the flights it identified.

According to the consent order, American said it seeks to avoid lengthy ground delays, and the 43 flights represent a fraction of 1% of the roughly 7.7 million flights that American and American Eagle operated 2018-21. The airline said it provided “substantial compensation” to delayed passengers, and has devoted more management attention to avoiding delays.

Most of the delays occurred at Dallas-Fort Worth International Airport, where American is the dominant airline, and others occurred in San Antonio and Houston when flights heading to DFW were diverted there. Numerous incidents occurred during thunderstorms, and American was unable to manage its airport gates to let passengers deplane.

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