Could a seat belt have saved them? Yesterday, a United Airlines flight from London’s Heathrow to Los Angeles was diverted to Montreal after the Boeing 777 was hit by severe turbulence. Ten people were hurt – some with broken bones.

People Flying Through the Cabin

My guess is, none of the injured were wearing seat belts. No, I’m not blaming them – I’m sure the pilot had the seat belt sign off – but the terrifying thing about turbulence is that comes out of nowhere, with no warning. Anything not secured, including laptops, luggage and people – can go flying through the cabin.

“You don’t want to end up on the ceiling like pancake batter, do you?”

I wrote about turbulence in one of my weekly air travel columns for ABCNews.com back in March, and spoke to a veteran flight attendant for American Airlines who remembered a scary incident early in her career when she was working in the galley when the plane began to buck: “I hit my head on a shelf and got knocked unconscious.”

This flight attendant now tells passengers to stay buckled up, no matter what the seat belt sign says: “You don’t want to end up on the ceiling like pancake batter, do you?”

What is Turbulence?

Turbulence is a natural phenomenon described by the Federal Aviation Administration as follows:

“Turbulence is air movement that normally cannot be seen and often occurs unexpectedly. It can be created by many different conditions, including atmospheric pressure, jet streams, air around mountains, cold or warm weather fronts or thunderstorms.” – FAA.gov

It can affect any plane, even Air Force One – as Present Clinton found out back in June of 1996 when the presidential 747 aircraft was hit by turbulence over Lubbock, Texas and one passenger (not the president) was injured.

Turbulence is Not Going to Break the Plane

Aviation experts say modern planes are built to withstand the worst turbulence. As Charles Feldman, a pilot/journalist told us, “You have a much better chance of having a space ship suck you out of your commercial jetliner and take you to another galaxy than your plane being broken up by turbulence.”

Still – it’s scary – and it can hurt you. What to do?

How to Avoid Injuries from Turbulence

Chances are excellent that you will not get hurt if you follow these 4 simple rules.

1. When the seat belt sign is “on” keep your seat belt buckled
2. When the seat belt sign is “off” keep your seat belt buckled
3. Avoid aimless walking around; learn in-flight exercises you can do in your airline seat
4. Avoid trips to the lavatory; use the facilities before and after your flight

“When the Plane Goes Down, You Go Up. Simple as That.”

In other words, sit there – buckled up. I know this isn’t easy during say, transatlantic flights, but listen to the sobering words of that veteran flight attendant: “When the plane goes down, you go up. Simple as that.”