The Southwest Airlines Co. plane which had a nearly 5-foot-long hole open during flight at 34,000 feet on April 1 had misaligned rivet holes where two parts of the fuselage were assembled, a U.S. safety board said.
Wear-induced cracks stretched from 42 of the 58 rivet holes along the 9-inch-wide fracture in the Boeing Co. 737-300 jet, according to the board’s statement today.
There were 123 people on the plane, which made an emergency landing in Yuma, Arizona. One flight attendant and one passenger were injured. The aircraft was delivered to Southwest in 1996 and had 39,781 takeoffs and landings prior to the incident.
Boeing said April 5 that cracks on the so-called 737 Classic weren’t forecast to occur until after 60,000 takeoffs and landings.
The Federal Aviation Administration on April 5 required checks on all 737-300s, 737-400s and 737-500s that have flown more than 30,000 cycles. Boeing said today that checks for cracks in the single-aisle planes have been completed on 75 percent of the 190 aircraft at risk globally.
Cracking has been found only on five Southwest jets previously identified, and it’s too early to speculate on the cause, Chicago-based Boeing said in a statement today.
Portions of the panels from the five planes, delivered between 1994 and 1996, have been shipped to Boeing, which is analyzing them, the company said in a statement.
“Boeing will not speculate on what the NTSB’s initial findings may suggest about the root cause,” the company said in its statement, adding that it is “fully engaged” in the investigation.
Southwest is confident that its aircraft meet the FAA directive requirements, company spokesman Brad Hawkins said. “Southwest Airlines looks forward to the results of the completed investigation,” Hawkins said.