Airline mechanic explains flight's walls falling apart

SAN CARLOS, Calif. -- American Airlines is still investigating the failure of an air duct system that blew out an interior wall panel on a jetliner Monday, forcing an emergency landing at San Francisco International Airport.

The interior walls of the aircraft around the window area are actually plastic covers -- they're not structural or part of the skin of the aircraft. Still, it was rather unsettling when passengers witnessed the covers popping and breaking in the middle of the flight.

"It was not a life-threatening problem," Bob Davis said.

He knows Boeing jumbo jets inside and out, having spent 36 years as an airline mechanic for TWA. Davis says, from what he's seen in videos and photos, as scary as it looked and sounded, the passengers and crew on American Airlines Flight 2293 were never in jeopardy.

"The real danger? There actually wasn't any real danger. The airplane was going to stay pressurized. The air is still coming into the airplane," Davis explained.

If a duct breaks or fails, Davis says it can create enough pressure inside the lightweight panels to make them buckle, but the structure itself -- the skin of the airplane -- wasn't compromised. Of course, passengers like Joan Denney didn't know that at that time. She was sitting right next to one of the broken wall panels.

"You think, 'I don't think we're going to make it.' And it was very scary, really weird," Denney siad.

"It was something that happened inside the cabin. The hull of the airplane, which is most important for the safety of the aircraft, was not penetrated. And so I am sure it was quite scary for the people inside that airplane, but at no time were they in real significant danger," ABC News aviation consultant Steve Ganyard said.

The airliner has been moved from SFO to Tulsa for repairs. As for the 184 passengers, most were able to board other flights by Tuesday morning.

American hasn't revealed exactly how old the plane is, except to say the average age of their fleet of 757s is 19 years.