Airport workers in Portland, Maine, had been compelled to filter of the way in which when a Southwest Airways jet on the morning of June 25 took off from a closed runway, in response to air site visitors management recordings.Controllers and pilots warned the crew of Southwest 4805 a number of occasions that the runway was closed, the recordings made by LiveATC.internet present. The incident is now beneath investigation by the Nationwide Transportation Security Board and Federal Aviation Administration, and Southwest says it’s engaged with each regulators.For the final a number of months the runway has been closed in a single day for a taxiway development venture, and it reopens every morning at 5:45 a.m., in response to the Portland Worldwide Jetport. A controller stated on the recordings that the tower can be closed in a single day.“There’s an airport automobile,” one voice warned over the radio.Stated one other: “The Southwest pulling on to 29, simply so you realize there’s a automobile on the runway and it’s nonetheless closed.”However the Southwest pilots apparently by no means heard the warnings. They had been recorded speaking on a unique radio frequency with regional air site visitors controllers close to Boston.The Boston controller later advised Southwest they departed three minutes earlier than the runway reopened.Boston controller: “That runway was closed.”Southwest pilot: “I assumed it opened at :45. There was no markings or wherever.”Controller: “It did open at :45, however you departed at :42.”Pilot: “That’s not what we’re displaying, however okay.”The FAA advised CNN the runway was certainly closed on the time, and that the “airport automobile exited the runway earlier than the airplane started its takeoff roll.”It’s unclear how shut the airplane got here to colliding with the runway crew. The tower controller advised the employees over the radio that he knew “you had been on the runway and needed to exit” due to the takeoff.Southwest stated the flight “continued safely to its vacation spot,” and referred inquiries to the NTSB, which stated it’s investigating and would make public a preliminary report on the incident subsequent month.That is the newest in a sequence of security incidents involving Southwest airplanes. Investigators are additionally probing current Southwest flights that got here dangerously near crashing close to Oklahoma Metropolis and one of many Hawaiian islands, in addition to a uncommon, unsafe in-flight swaying referred to as a Dutch roll.For extra CNN information and newsletters create an account at CNN.com