What happened
On June 25, 2024, at approximately 0543 EDT, a Boeing 737-79P, registration N7861J, operated by Southwest Airlines, departed from a closed runway at Portland International Jetport (PWM) in Maine. The flight was a scheduled domestic passenger service bound for Baltimore/Washington International Thurgood Marshall Airport (BWI).
At the time of departure, the Portland air traffic control tower was closed, and the airport was operating using UNICOM and common traffic advisory frequencies. While a NOTAM was in effect for the closure of runway 11/29 due to construction, the crew did not observe any visual indicators of the closure, such as lighted "Xs," or any equipment on the runway surface. The crew noted that a truck had exited the runway and moved to the terminal area prior to their takeoff.
All 131 passengers and 5 crewmembers were not injured and deplaned at the gate in Baltimore without incident.
The investigation
The NTSB investigation involved the review of the flight's dispatch release, weather packets, and NOTAMs. The investigation also included interviews with the flight crew and the dispatcher, as well as the analysis of the digital flight data recorder.
Investigators found that the flight crew's weather packet contained a message stating that all flights departing PWM before 0545 must contact a dispatcher for a briefing regarding the use of runway 18/36. The crew did not see this message and did not request a briefing. Additionally, while the crew noted a NOTAM regarding the closure of runway 29 on weekends, they did not identify a separate NOTAM specifying that the runway was also closed on weekdays until 0545. The crew stated the relevant NOTAM was obscured underneath another application on their electronic flight bags.