American Airlines (AA, Dallas/Fort Worth) has been fined USD1.6 million by the US Department of Transportation (DOT) for tarmac delay violations in 2013 and 2015. The fine equals the highest given previously for similar violations, against Southwest Airlines (WN, Dallas Love Field) in 2015.

The DOT’s investigation found that twenty flights at Charlotte International on February 16, 2013, six flights at Dallas/Fort Worth on February 27, 2015, and one flight at Shreveport Regional on October 22, 2015 were subject to lengthy tarmac delays. Acknowledging that poor weather was a factor in some of the incidents, the DOT however found that the scheduled carrier was not adequately prepared and did not take appropriate measures to prevent further delays.

The fine includes USD602,000 in compensation which has already been paid by American Airlines to affected passengers. A further USD303,000 is credited to the carrier’s costs of a surface management system at Charlotte and Dallas-Forth Worth to monitor ground locations of aircraft. The total that American is required to pay to DOT is USD695,000.

American Airlines manages a fleet of 926 aircraft, employs more than 61,000 people, and in 2015 posted a net profit of USD7.61 billion.