Southwest Airlines Flight WN4761 declared an in-flight emergency on Monday, July 20, 2026, after the crew detected indications of a suspected fuel leak while cruising at 37,000 feet over South Carolina, prompting an expedited diversion to Charleston International Airport.
The flight, a regularly scheduled service from Orlando International Airport (MCO) to Manchester-Boston Regional Airport (MHT) in New Hampshire, departed Orlando’s Terminal A, Gate 125, at 8:54 a.m. EDT. The aircraft, an 11-year-old Boeing 737-800 registered as N8662F, climbed normally and had been airborne for about an hour before the anomaly was detected.
Acting in accordance with standard safety protocols, the flight crew transmitted a squawk 7700 transponder code, aviation’s broadest emergency signal, alerting air traffic control across the region that the aircraft required priority handling. Controllers cleared the jet for an expedited descent into Charleston International Airport (CHS), where emergency response vehicles were positioned on standby.
The aircraft landed safely on Runway 15. No injuries were reported among passengers or crew.
Southwest Airlines moved quickly to limit disruption for the stranded travelers, dispatching a replacement aircraft, a newer Boeing 737 MAX 8 registered as N8881L, to Charleston. After a four-hour ground delay, passengers reboarded and continued to Manchester, arriving approximately five hours behind schedule. Under Department of Transportation rules, affected passengers are entitled to a 75 dollar delay voucher from Southwest Airlines.
The original aircraft remains in Charleston, where maintenance teams are conducting a thorough inspection to determine the root cause of the fuel leak indication. As of Monday evening, it remained unclear whether the warning reflected an actual mechanical leak or a sensor or valve anomaly, a distinction that has proven significant in comparable incidents involving the 737-800 in the past.
