Photo Credit: AP
In this photo provided by passenger Brenda Reese, unidentified passengers take photos with cell phones of a hole in the cabin on a Southwest Airlines aircraft Friday, April 1, 2011 in Yuma, Arizona.
Boeing Co. didn’t keep manufacturing records that might have allowed investigators to determine why the fuselage on an American Airlines 757-200 jetliner tore in flight last year, according to the U.S. National Transportation Safety Board.
That lack of records has also hampered the NTSB’s efforts to pinpoint the cause of a larger tear that forced the crew of a Southwest Airlines Co.737-300 to make an emergency landing April 1, according to two government officials familiar with the investigation. They asked not to be identified as the probe is ongoing.
“Records of manufacture for the skin panels on the accident airplane and the other airplanes with fuselage skin cracking were not retained, and were not required to be retained,” the NTSB, which investigates U.S. transportation accidents and recommends safety improvements, wrote in a report on the American incident, dated Sept. 19, on its website. “Therefore, a cause for the manufacturing non-conformance could not be identified.”
The American jet’s skin was too thin, which led to cracks, the NTSB found. Without records detailing how the plane was built and inspected, the safety board wrote, it could not determine the source of the manufacturing defect.
In the Southwest incident, a 5-foot section of the jet tore open at 34,000 feet, triggering an explosive decompression and injuring one flight attendant. The plane made an emergency landing in Yuma, Arizona.
The accident has been tied to rivets not being secured properly when the jet was built in 1996, according to the NTSB and Boeing airplanes chief James Albaugh.
Records of how those rivets were installed and inspected don’t exist, the officials told Bloomberg.
The reason records don’t exist was detailed in the safety board’s report on the American incident, in which an 18- by 7- inch tear opened above the left-side front passenger door at 32,000 feet, about 16 minutes after the jet left Miami Oct. 26.
The jet made an emergency landing in Miami. No one was injured.
During its investigation, the safety board discovered two other 757s - one operated by AMR Corp. (AMR)’s American, the other by UAL Corp.’s United unit - with thin skin and similar patterns of cracking. Manufacturing records for those planes also weren’t kept, the safety board wrote.
The Federal Aviation Administration, which regulates airlines and aircraft manufacturers, in 2009 revised its rules to require that manufacturers keep records for at least five years, according to the Federal Register. In the case of “critical” components, manufacturing records must be kept for at least 10 years.
Boeing “diligently” follows the FAA’s rules for record retention, Julie O’Donnell, a spokeswoman, said by telephone. She declined to elaborate.
The previous rule, which dated to 1964, required that records be kept for two years.
One aviation manufacturer, General Electric Co. (GE), advised the FAA to require that records be kept for 40 years. The agency said in the final rule that it was deferring to the advice of an industry committee. A manufacturer “may maintain records longer if it chooses,” the FAA said.
The rule took effect in April 2010, according to the Federal Register, and wouldn’t have helped investigators in the American or Southwest probes as both jets were built more than 10 years ago.
“Manufacturing records can be helpful in an accident investigation, but they are not always essential,” the FAA said in an e-mailed statement yesterday.
“If a manufacturing flaw is detected on an aircraft, the best way to determine whether similar flaws exist on other aircraft is to conduct a physical inspection of those aircraft.”
The Southwest tear was one of the most serious malfunctions of aircraft skin since an Aloha Airlines 737-200 almost broke apart on April 28, 1988. A flight attendant was sucked out of the plane and fell to her death after an 18-foot section of the fuselage opened over Maui.
The FAA requires that jets be built to withstand cracks and tears in the aluminum skin. Boeing builds its planes with an thicker layer of skin every 20 inches designed to stop cracks from growing.
The Southwest skin cracked through two of the thicker strips before it halted, meaning that the measures designed to prevent an aircraft breakup failed, according to preliminary findings of the NTSB investigation.
The NTSB has investigated several cases of jet skins tearing open in recent years, prompting the agency to hold a two-day forum on the topic starting today at its Washington headquarters.