SOUTHWEST PILOTS MISSED KEY NOTICE BEFORE CLOSED RUNWAY TAKEOFF

(Bloomberg) -- The flight crew on a Southwest Airlines Co. aircraft that took off from a closed runway in June overlooked a key notice warning of the closure, US safety investigators said in a preliminary report.

Flight 4805 departed on June 25 from the closed runway in Portland, Maine, just before 5:45 a.m. Prior to takeoff, the crew reviewed an electronic weather packet that included 32 notices to air missions, or NOTAMs, which alert pilots to changes that may affect operations.

The crew noticed one document warning that runway 29 would be closed during certain times on Saturdays and Sundays, but missed a separate brief addressing closures on other days of the week, the National Transportation Safety Board said in a report. The crew also didn’t see a message about a different runway that detailed the procedures for all flights departing before 5:45 a.m.

The plane carrying 136 passengers and crew arrived safely at its destination in Baltimore, but the mishap was serious enough to draw the attention of both the NTSB and the Federal Aviation Administration, which is also investigating the event.

According to the NTSB, the captain and first officer said they received information from software applications that appeared to indicate the runway was open. The first officer also announced several times, including on the universal communication frequency, that they planned to take off from runway 29.

The Portland air traffic control tower was closed at the time of the departure so the pilots had to communicate with the Boston Air Route Traffic Control Center, which gave them a clearance and flight instructions, according to the report.

The pilots said that prior to takeoff they saw a truck exit the runway but made sure it had moved out of the way before applying power. They also said they didn’t see any signs or indications that the runway was closed when they departed.

“We are addressing the matter through our safety management system and continuing to participate in the ongoing investigation,” a Southwest spokesman said.

--With assistance from Mary Schlangenstein.