Transcript for Plane passengers describe 30,000-foot plunge
Terrifying moments in the sky, a plane plunging nearly 30,000 feet in just minutes, oxygen masks, you see them right there, deployed. Now we're hearing from some passengers on board that plane and David Kerley has more. David, good morning. Reporter: Good morning. This shows you how quickly something can happen at altitude and how fast the pilots have to react. It was sudden and shocking for the delta passengers. I was losing it because you really just didn't understand what was going on. It was so scary. Reporter: The jetliner nosing down dramatically losing altitude. Some frightened passengers texting their loved ones. You know, I thought this is how it's going to end so took my son and hugged him up against my chest as hard as I could. Reporter: The oxygen masks dropping suggesting that the Boeing 767 could be depressurizing. The air so thin with little oxygen at altitude, minutes matter. One of the flight attendants I believe grabbed the intercom and repeatedly stated do not panic. Reporter: Delta said the crew of the flight got a warning, irregularity and the procedure is get to 10,000 feet so no warning from the piles. It's scary in the cabin but the pilots don't have time at that initial point. Each of those oxygen masks provides about ten minutes of useful oxygen. Meaning that the pilots have a very short amount of time to get the airplane down to a lower altitude. Reporter: In just eight minutes the jet lost 30,000 feet in altitude from 39,000 feet to 10,000 where the masks are not it doesn't appear this jet actually lost pressure. But it is a real danger. In 2017 an American airlines commuter jet lost pressurization. At least one passenger lost consciousness. And this ryanair jet had to lose nearly 30,000 feet in altitude when it did lose cabin pressure. It's actually an uncommon occurrence and so you always see this happy ending, scary for the people in the back, but well handled by the crew. Reporter: The jet diverted to tam pa the passengers were rebooked to get them to their final destination of ft. Lauderdale. Delta says they flew in a special team to look at the aircraft but so far no indication why the pilots got the warning light. As we say, everyone is okay. Still a lot of questions. Thanks so much.
This transcript has been automatically generated and may not be 100% accurate.