Transcript for Southwest Flight Dips 20,000 Feet in 11 Minutes
Now, to frightening moments onboard a southwest plane. Passengers very fearful when the pilot announced the plane was going down. Abc's david kerley has that story for us. Reporter: This morning, the faa wants to know why a southwest jetliner took a nosedive, after what passengers say they heard from the pilot. He says, we're going down. And everybody's looking around like, is this a joke? Are you serious. And then, it starts to nosedive. Reporter: The jet was losing altitude fast. We were clinching hands and say I love you. And kissed. I shut my eyes just waiting for it all to be over. Reporter: Southwest airlines says the pilot of the 373 from tampa to raleigh, did declare an emergency. Still working it out. We just want to get it -- Reporter: It was a cockpit alarm, showing a problem with the plane's pressurization. The plane dove down to 10,000 feet in just 11 minutes. That is standard procedure. But passengers thought it was the end and made desperate attempts to send final messages to loved ones. It says, I love you alyssa. My plane is going down. Reporter: Southwest says the pilot only communicated that he was initiating a decent to lower altitudes. That's not what passengers say they heard. You could tell he was struggling. I wouldn't tell if he was putting an oxygen mask on or something. And the last thing he said, we're going down. One of the things you don't ever want to hear on an airplane. Reporter: Even though the jet landed safely and is back in service, southwest did offer each of the passengers a $200 voucher for the wild ride into raleigh. For "good morning america," david kerley, abc news, washington. And just so thankful nobody was hurt.
This transcript has been automatically generated and may not be 100% accurate.