Overview

• Delta confirms more than 300 A320-family aircraft are in a replacement program that began in 2022 and is now over 90% complete.
• The work targets leaks that can allow engine oil vapors to enter the bleed‑air supply, exposing passengers and crew to neurotoxic compounds.
• A Wall Street Journal investigation reported incident rates increasing in recent years, with A320-family jets frequently implicated.
• Delta says it is evaluating alternative synthetic turbine oils from multiple manufacturers to mitigate contamination risk.
• United cites proactive monitoring and APU seal replacements, Frontier says cases are rare, and executives note the Boeing 787’s different air system avoids the issue.