SEATTLE (AP) - About 20 minutes after takeoff, passengers on Alaska Airlines Flight 536 to Burbank, Calif., felt their ears popping, then a loud noise shook the plane and oxygen masks dropped out of the ceiling as the plane dropped from about 26,000 feet.
As a general aviation pilot, passenger Jeremy Hermanns, 28, knew the air popping was a bad sign.
"This was absolutely terrifying for a few minutes," said the Los Angeles resident returning home from a holiday visit to his parents with his fiance.
The MD-80 plane was quickly stabilized, but passengers spent the next 25 minutes tearful and anxious until safely making an emergency landing Monday afternoon at Seattle-Tacoma International Airport.
A foot-long hole in the fuselage of the jet had caused the plane to lose cabin pressure, authorities said Tuesday.
None of the 140 passengers or five crew members was hurt, Alaska Airlines spokeswoman Caroline Boren said.
The National Transportation Safety Board and the Federal Aviation Administration were investigating, along with the airline and the Port of Seattle.
A ramp worker has acknowledged he failed to immediately report striking the plane at the gate Monday with a baggage cart or baggage-belt machine, NTSB spokesman Jim Struhsaker said.
The worker told the agency that although the vehicle touched the plane, he was not aware he had dented it, Struhsaker said.
The bump created a crease in the planes aluminum skin, which opened up into a 12- by 6-inch gash as the plane came under increased pressure at 26,000 feet, Struhsaker said.
On Tuesday, Alaska Airlines contacted the Port of Seattle "and asked our police department to take a hit-and-run report," port spokesman Bob Parker said Tuesday evening. "Were coming into this a full 18 hours after the fact. We got involved after Alaska Airlines reported a hit-and-run involving their airplane."
The worker was employed by Menzies Aviation, a British company that Alaska contracts with to provide baggage handling and other ramp services at Sea-Tac, Boren said.
Alaska Flight 536 left the airport for Burbank just before 4 p.m. Monday. The flight crew reported a loss of cabin pressure about 20 minutes later, Boren said. Oxygen masks deployed for passengers and the plane made a rapid descent, landing at Sea-Tac just before 5 p.m., she said.
The hole was on the right side of the plane between the forward and middle cargo holds, Boren said. It was about 4 feet beneath passenger windows.
"I can tell you that there was a ramp vehicle that did make contact with the aircraft prior to the aircraft leaving for Burbank," she said. She did not know the exact type of vehicle, the exact sequence of events of the contact being reported, nor the status of the worker involved.
About 430 Menzies workers provide services for Alaska at Sea-Tac, Boren said. Meetings were being held with them to review safety procedures, including the "rapid and thorough reporting" of incidents on the ground, she said.
"Were working with the NTSB to review all the information relative to this event," Boren said.
The plane was being repaired and should be back in service within a few days, she added.
Menzies Aviation did not immediately return a call for comment Tuesday night.
Last May, Alaska Airlines laid off nearly 500 baggage handlers and other ramp workers at Sea-Tac, saying it needed to trim costs amid rising fuel prices and fierce competition from low-cost carriers.
In a statement then, Alaska said hiring Menzies Aviation to provide those ramp services at the airport would save $13 million a year.
Alaska Airlines is the nations ninth-largest carrier. Together with its sister airline, Horizon Air, it flies to more than 80 cities in the United States, Canada and Mexico.