Government Orders 737 Inspections in Wake of Crack in Southwest Jet

Southwest Inspects 79 Planes, Finds Stress Cracks in Five and Promises Repairs

Post a Comment

By LISA STARK, MATT HOSFORD and BRADLEY BLACKBURN

April 5, 2011

PrintRSS

Font Size:

Share:

EmailTwitterFacebook

More

The federal government will today order emergency inspections on 175 Boeing 737 airliners, and is rethinking its approach to plane inspections after a Southwest Airlines jet tore open in mid-flight Friday night.

More Video

Watch: More Cracks in Southwest Planes

Watch: Southwest Scare Tests Safety Knowledge

Watch: Safety in the Skies

Inspections will initially focus on 175 planes, used by airlines around the world, that make frequent takeoffs and landings. Eighty of the planes are in service in the United States, most of them for Southwest Airlines.
The government is particularly concerned about older 737-300, 737-400 and 737-500 jets that have taken off and landed more than 30,000 times. Jets that have accumulated many flight cycles are apparently more likely to develop the sort of fatigue cracks that may have caused the tear in the skin of the Southwest 737-300 last week.
As the nation's planes age, more jets could cause concern and require inspection for such fatigue cracks.
Inspectors use something called eddy current technology, passing an electric current through an aircraft's skin to look for small cracks. If any warning signs are detected, ultrasound and X-ray tools are then used for a closer examination. In some areas, a plane's skin can be as thin as a nickel.

Fatigue Cracks Found in Three Other Southwest Jets

Southwest is expected to resume its regular schedule today. It said this morning that it had finished inspections of all 79 of its 737-300s, which were removed from service after the weekend. The airline said it uncovered fatigue cracks in five planes, and would keep them out of service until Boeing recommends how to repair them. Southwest said it believes its inspection process complies with the government's order.
Southwest had cancelled hundreds of flights to accommodate inspections after Friday's ordeal, when Southwest flight 812, en route from Phoenix to Sacramento, Calif., was diverted to a military base at Yuma, Ariz., after a section of the plane's fuselage ripped open, depressurizing the plane and exposing the sky to passengers.
The five-foot section of the plane's fuselage that opened up has been sent to Washington, D.C., for detailed microscopic analysis.

nspectors Probe Southwest Jet's Crack

The jet came apart at a seam where two pieces of metal are riveted together, an especially dangerous location because the skin of the plane can essentially unzip, experts said.
"We have clear evidence that the skin separated at the lower rivet line," Robert Sumwalt, a NTSB Board member, said.
The damaged aircraft is 15 years old and had been through more than 39,000 takeoffs and landings.
"When airplanes take off and land, aircraft are pressurized. The internal cabin is expanded and contracts just a little bit," said Steve Ganyard, a former military pilot who is a consultant for ABC News. "You're exercising the skin of that aircraft."
The Southwest jet had what is known as a D-check in March 2010, the most comprehensive check for an airplane.
Based on modeling and previous flight experience of Boeing 737-300s, it was believed that the cracks could not develop in this area of the plane.
"Now we may have to look at airplanes in places we never thought we would have to check before," said Ganyard.

Southwest Flight 812 Drops 20,000 Feet in Four and a Half Minutes

On Friday's harrowing flight, the plane climbed normally toward 36,000 feet. Flight attendants had just taken drink orders when the plane's 118 passengers reported hearing loud pops. Then, with the plane at approximately 34,000 feet, the roof opened up above the cabin's overhead luggage compartments and oxygen masks dropped in front of passengers. At least one flight attendant passed out.
"Your ears instantly start to hurt really bad. You feel like you're going to black out," said Wade Allemand, a passenger.
The pilots turned the jet sharply to the right and pushed the nose down, descending more than 20,000 feet in just four and a half minutes.
Passengers had a short amount of time to get their oxygen masks on.
"It depends on what the decompression is. Sometimes it's minutes, sometimes it's two to three seconds," Lauren Jarmoszko, a flight safety instructor, said.
Loss of oxygen affects cognition, memory and reaction time. It can also lead to brain damage.
In a rapid decompression, like the Southwest flight, oxygen masks are designed to deploy quickly. There are also instances of slow decompression, usually caused by a small leak in a window or door seal. In those cases, passengers and crew may not even notice the first effects: fatigue, mental confusion, and dulled reflexes.
The captain on Flight 812 had 19 years experience with Southwest, while his first officer had seven years of experience, and he received assistance as typical when declaring a emergency, according to the NTSB.
Some terrified passengers clearly thought it was the end. One woman whose husband was on the plane received a text from him -- "Plane going down. Love you."
However, the plane was able to land at Yuma Marine Corps Air Station/International Airport at 4:07 p.m. Friday, said Ian Gregor of the Federal Aviation Administration.
Passengers applauded the pilots upon landing, called loved ones and waited for a new Southwest jet to pick them up and take them on their way.
ABC's Jessica Hopper contributed to this report.