Twice in the last month – a Continental Airlines jet in Denver and a US Airways jet in New York – we’ve seen significant plane crashes that have been survived by all onboard. It’s a testament to the skill of airline crews and the steps that have been taken to make airplane cabins safer.

In 2005, I wrote about safety changes that had improved survivability. Newer planes have stronger seats so passengers don’t go flying on impact, for example. Overhead bins, carpets, cushions and other materials burn only at higher temperatures and don’t give off noxious fumes, giving passengers more seconds to escape.

The story included tips on walking away from crashes. Perhaps those tips are worth reviewing again now.

Know the exits in front of you and behind – and count how many rows away they are.

Brace for impact. Head against seat in front of you. It works.

Leave your luggage. No laptop is worth dying for.

Stay low and breathe slowly. Smoke collects near the ceiling of a plane. Moving hunched over works best if you can (if you crawl, you might get trampled). And know that breathing aircraft-fire smoke is going to hurt; the slower you breathe, the better.

Get through exits quickly, but one at a time. Doors are small, particularly the exits over the wings; they can easily become clogged with bodies, with deadly consequences.

Don’t stop to remove your shoes. Slides are tougher these days, so you don’t need to worry about ripping them.

Help at the bottom of a slide if you can, or move out of the way on a wing. Flight attendants typically ask able-bodied volunteers to assist sliding passengers. Having someone help you up and move you out prevents piles of people at the bottom — a frequent problem in evacuations — and makes it easier for scared passengers to jump. Videos of real emergency evacuations repeatedly show that volunteers wait only so long before running off themselves.

The biggest threat in a survivable crash is fire. Jet fuel (essentially, kerosene) burns very hot at 1,500 degrees, hotter than the melting point of aluminum. In addition, materials used in manufacturing airplanes do give off toxic smoke, so the fuselage can become a deadly gas chamber in as little as 90 seconds. Just as quickly, heat can become so intense that a “flashover” occurs, where the entire cabin explodes in instantaneous combustion.

Bottom line: Get out quickly. To be certified, a commercial airliner has to have enough exits to get a full load of passengers out within 90 seconds, using only half of the doors.

One advantage the people on board the US Airways flight had in the Hudson River: It was daytime. Researchers say evacuations are slower at night or in the rain. And the types of passengers on board matters, too. Having frequent travelers on board typically makes evacuations faster.

In 1984, a Pacific Western 737 had a engine failure that spewed white-hot parts and led to an intense fire in Calgary, Canada, with 119 onboard. There were no fatalities — partly because, researchers said, 75% of passengers were frequent fliers who knew the plane and the exits. There were no handicapped travelers, elderly passengers or children on board.

A year later, a British Airtours charter to Greece had a similar engine failure and fire on takeoff from Manchester, England. Of 137 people on board, 55 died. Panicky passengers clogged a narrow aisle, producing gridlock.