Delta Replaces APU Engines on Airbus A320 Fleet to Address Toxic Fume Concerns

Delta Air Lines is undertaking a major maintenance program to replace auxiliary power units (APUs) on more than 300 of its Airbus A320-family aircraft after years of toxic fume complaints from crew members. The airline confirmed to CBS News that the initiative, which began in 2022, is now more than 90% complete. Delta did not disclose the cost of the project.

APUs—small engines that power aircraft systems on the ground and provide backup power in flight—have been linked to cabin air contamination when seals fail or oil leaks occur. These incidents can allow toxic fumes to enter the cabin’s air supply, posing potential health risks to flight crews and passengers.

Flight attendants have raised concerns about the issue for years. “I felt like I might die, and I thought, you know, I wonder what my mom is going to think—I went to work, and you know, I may not make it,” flight attendant Vanessa Woods told CBS News in 2016 about breathing engine fumes on duty.

A recent Wall Street Journal investigation found that leakage of fumes most commonly occurs on Airbus A320-family narrowbody jets. Medical specialists also warn of possible long-term effects. Dr. Robert Harrison, an occupational medicine expert at the University of California San Francisco who has treated more than 100 flight crew members for fume exposure, told CBS News that breathing contaminated air can lead to nervous system problems and other health issues.

Delta says it is also exploring new synthetic turbine oils from multiple manufacturers to reduce the risk of fume events.

Other carriers are taking notice. United Airlines CEO Scott Kirby told CBS News that the issue is something he has “personally been focused on for over a decade.” United operates a “proactive maintenance program” that tracks oil consumption and pressure on its aircraft engines and preemptively replaces APU seals to prevent leaks that could lead to cabin contamination. Kirby added that newer aircraft such as the Boeing 787 Dreamliner use a different design that mitigates the risk.

Barry Biffle, CEO of Frontier Airlines, which also operates an Airbus fleet, said incidents are “very rare” but that the company is monitoring the issue closely.

Delta’s sweeping APU replacement program underscores how airlines are responding to crew safety concerns and heightened public scrutiny. By swapping out older APUs and testing alternative oils, the carrier aims to reduce fume events and restore confidence in the cabin environment for both passengers and employees.

Sources: AirGuide Business airguide.info, bing.com, cbsnews.com, wsj.com