Talk about a rough flight. Twenty-seven passengers aboard an Aeroflot Flight between Russia and Bangkok were injured after their flight hit major turbulence. Some, suffering broken bones.

Anyone who travels enough probably has a story or two about a rough flight. And once it happens, you might better appreciate that lap belt they're always telling to keep buckled.

“I didn't expect anything to happen,” said Carlene Williams.

Williams, a frequent flier who was traveling out of Tampa International Airport Monday, remembers it like it was yesterday. Overhead bins flying open during her flight leaving New York when the plane suddenly hit turbulence.

“It's like a gripping thing. It's like anxiety. Very very anxious and nervous,” said Williams, “And I mean, if you're religious you start praying right away.”

Aeroflot's May Day mayhem is a vivid reminder, say seasoned travelers, of just how fast things can go from terrific to terrifying.

“Clear day. It just kind of came out of nowhere,” recalls Tim Stanko.

Stanko, also flying out of TIA Monday, says he was on a plane from Denver to Tampa when suddenly - in crystal clear weather - his flight plummeted about 2,000 feet.

“I was traveling by myself, but I saw a lot of families that were very terrified at what had happened, and proceeded to get sick and weren't able to be calmed down after that,” he said.

Severe clear air turbulence, the kind that left the Aeroflot passengers battered and bloodied, is actually rare, say aviation experts.

Unlike wind shear, it's also difficult to see or detect. Pilots often rely on each other to report it.

“We communicate. We say the right here 33,000 is no good. 35,000 is better. Or we have to go down to 27,000 to get a smooth ride,” said 10News WTSP Aviation Expert Mark Weinkrantz.

Weinkrantz is also a commercial pilot. When he tells his passengers to keep their seatbelts fastened during the flight, this is the kind of scenario that worries him.

“As a thunderstorm develops, you can project energy a mile above where you actually see a cloud. So, they could be flying over what they thought were soft puffies, and it could've actually just been a chimney for something else developing,” said Weinkrantz.

Passengers say it only takes one white-knuckle experience to get the message.

Keep that lap belt buckled, they warn.

“Why not?” said Stanko, “Where are you going to go on that plane, you know?”

Williams agreed.

“When it's over, you realize it wasn't so bad. But in that moment, you like, rip your seat, and you're like OK just get me through this just get me through this,” she said. “That's all you want to happen.”