'We're going down' - Flight Scare from Southwest Airlines

The pilot of a Southwest Airlines flight gave passengers a scare Tuesday when he announced over the loudspeaker that the plane was "going down."

"He said, 'We're going down,'" Shelley Wills, one of the passengers on the Boeing 737 en route from Tampa, Fla., to Raleigh-Durham International Airport, told ABC's affiliate there. "And everyone is looking around like, 'Is this a joke? Is he serious?' And then you felt the nosedive."

"At first it sounded like someone was coming over the PA to talk," Grace Stroud, another passenger, told CNN. "Then it sounded like shots through the cabin, twice, back to back. Seconds later, the panicked captain said, 'We're in trouble, we're going down.'"

Wills said she tried to console a woman seated next to her who was clutching her chest. "I'm thinking, 'Oh my God, she's going to scare herself into a heart attack,'" Wills said.

She said she even texted her daughter goodbye. "[The text] says, 'I love you Alyssa. My plane is going down.' I thought I was going to die, and that's what everyone on that plane thought. That we were all going to die, just by one word of the captain. I just think they could have handled it a little differently."

In an email to Stroud obtained by CNN, Southwest said the pilot “inadvertently activated the PA system.”

A Southwest spokeswoman confirmed there was an emergency.

"Flight 3426 experienced a maintenance alert as they were on descent into RDU," Southwest said in a statement. "The captain declared an emergency and descended the aircraft to 25,000 feet where the alert was resolved. Throughout the remainder of the descent the flight was normal, landed uneventfully, and was not met by emergency vehicles."

The FAA said it is investigating.

It's not the first time Southwest Airlines has had a scare at Raleigh-Durham. In September, a Southwest flight bound for Chicago struck a bird, damaging an engine. The pilot alerted the passengers, turned the plane around and landed safely at the airport to the delight of the 124 people on board.

"Everyone clapped," Shelly Tranchita, one of them, told WRAL-TV. "It was an uproar. It was a beautiful thing. We landed and were safe and it was a huge relief."

"I high-fived the guy next to me over his crying girlfriend," George Shackleton, another passenger, added.

Last month, Southwest fired a veteran pilot whose nosedive landing at New York's LaGuardia Airport in July injured 16 people. According to the National Transportation Safety Board, the pilot took control from the first officer just before the Boeing 737 hit the runway.