American Airlines grounds Airbus A321 after fume incident forces return to Los Angeles

The Airbus A321-200 involved is 11 years old and was originally ordered by US Airways in 1997 before being delivered to American Airlines in 2014 following the airlines' merger. As of July 31, 2025, ch-aviation data indicates the jet had logged 34,881 flight hours and completed 14,448 cycles. It features a three-class layout with seating for up to 190 passengers: 20 in business class, 35 in economy plus, and 135 in economy class.

Prior to this event, Flightradar24.com records show the aircraft operated flights between West Palm Beach (PMI) and Charlotte (CLT), CLT and Orlando (MCO), as well as MCO and Los Angeles (LAX). The alternative flight to New York was also handled by another A321-200 from American Airlines’ fleet. Currently, the airline operates a total of 218 A321-200s with an average age of just over thirteen years.

Issues with toxic fumes have been reported more frequently on Airbus A320 family jets. According to a Wall Street Journal investigative report published on September 13, 2025, such incidents are increasing without significant corrective action. These events are often attributed to leaks associated with the auxiliary power unit (APU), which can allow oil fumes into the cabin via the ‘bleed air’ system used on most modern commercial jets except for models like the Boeing 787.

Robert Kaniecki, neurologist and consultant to the Pittsburgh Steelers, told the Wall Street Journal that “the fumes are toxic and can cause brain injury and permanent damage to the peripheral nervous system.”

In response to these concerns within the industry, Delta Air Lines has begun replacing APUs across its fleet of more than 300 Airbus A320 family aircraft—a process started in 2022 according to CBS News reports. Delta operates a total of 321 Airbus A320 family jets including A319s, A320s, and A321s.

The APU serves as a small engine located in an aircraft’s tailcone that supplies electrical and pneumatic power when main engines are off. Leaks from this unit can introduce harmful substances into cabin air because passenger breathing air is drawn through engines using bleed air systems—a common feature except on certain newer models such as Boeing’s Dreamliner series.