UNITED AIRLINES FLIGHT 811 : Damaged Jetliner Has a History of Structural Trouble
The United Airlines jumbo jet that ripped open early Friday in the sky near Hawaii was an aging Boeing 747 with structural problems in its maintenance history.
Although investigators are leaning toward structural failure as the most likely explanation for the truck-sized hole in the fuselage of the aircraft, other possibilities include problems in latching its right-side cargo door--or a bomb.
Investigators from the National Transportation Safety Board, as well as representatives of Boeing Commercial Airplanes, flew to Honolulu to inspect the damaged plane. Their findings are crucial to Boeing, which has experienced difficulties with aging aircraft, and has been troubled as well by mis-wired emergency systems in newer planes and by 747 production delays.
Parts of Wing Fell Off
Structural problems that have plagued the United plane are cited in service difficulty reports filed to the Federal Aviation Administration by the airline, which is responsible for its maintenance. These reports note, for instance, that two years ago, passengers and a flight attendant reported seeing parts of its left wing fall off on landing.
In addition, orders issued by the FAA for mandatory inspections and repairs on this and other 747s include one issued last year calling attention to damaged cargo doors that could open in flight and “which could result in rapid decompression of the airplane.” The hole in the United jet surrounds and includes one of its cargo doors.
Authorities also were looking into a recent bomb threat phoned to a Honolulu radio station demanding the release of a Japanese Red Army commander arrested in Tokyo a year and a half ago. If the commander was not released by Friday, the caller said, “there will be an accident (on) an American airline.”
The aircraft is 18 years, 3 months old, the 89th to roll off Boeing’s assembly line. It was delivered new to United on Nov. 3, 1970. Although 88 Boeing 747s are older, the plane was delivered within Boeing’s first year of 747 production. Its age means that the aircraft is nearing the end of what Boeing calls the “economic service life” of its planes.
At 20 years, Boeing officials say, their airplanes begin cracking so frequently that operators must inspect them more often--and make whatever repairs are necessary to continue operating them safely.
Age alone, however, does not determine the structural deterioration of aircraft. So do flight hours and the number of takeoffs and landings, called cycles. This aircraft had logged 58,000 hours and 15,000 cycles. A so-called “high-time” 747, said Boeing spokesman David Jimenez, has 79,000 hours of operation and 26,000 cycles.
Found Crack in 1980
Eight years worth of service difficulty reports, obtained by The Times, show that the United jet suffered structural problems as early as 1980, when maintenance crews found a crack in one of the stringers in its inner structure.
Two years later, a main tire assembly fell off a landing gear. Maintenance engineers blamed a fatigue crack. Two years after that, in 1984, maintenance crews found multiple cracks in the plane’s inner skin in the cockpit area. One crack was 20 inches long.
During an inspection in 1986, ordered by the FAA, cracks were found in the fuselage frame forward of the cockpit area. The inspection was ordered for all 747s after severe cracks were found in the fuselage frames on several other jumbo jets.
Six months later, during a comprehensive four-day inspection called a “C-Check,” one of the right wing flaps on the United plane was found to be touching its No. 3 engine pylon. Maintenance crews removed the pylon. They discovered corrosion and cracks one inch and four inches long in the plane’s inner structure.
Spoiler Came Off
A month after that, a service difficulty report notes: “Aircraft arrived with flight log report that passengers and flight attendant reported parts of left side spoiler came off” as it landed at San Francisco. The spoiler is a trailing edge wing flap that is raised to brake the plane and to “spoil” its lift as it touches down.
In all of these reports, said Bobbie Mardis, an FAA spokeswoman, “there is nothing that shows any significant problems that point toward what happened today.” She called the 16 service difficulty reports that were filed on the United aircraft over the last five years “about average.”
Lawrence M. Nagin, senior vice president for United’s corporate and external affairs, said during a news conference at the airline’s suburban Chicago headquarters: “The integrity of the plane speaks for itself in that it came back to Honolulu.”
The FAA’s order last year to inspect 747 cargo doors was issued after one of the doors on another jumbo jet partially opened in flight because of a damaged lock. By Dec. 31, 1989, the FAA order said, all airlines should reinforce these locks with steel plates.
When asked whether the lock had been reinforced on the United jet, Russell Mack, the airline’s vice president of corporate communications, said the modification had been made on six of the 25 United 747s in the same model series.
But Mack added: “This plane had not been done.”
Nagin said the plane underwent another “C-Check” just 88 days ago and a less extensive “A-check” was completed Feb. 15.
“Everything, the whole inspection was fine,” Molinaro said.
In addition to such orders issued by the government, Boeing issues periodic service bulletins, calling the airlines’ attention to problems encountered with its airplanes and recommending repairs.
Service Bulletins
Jimenez, the Boeing spokesman, refused to say how many 747 service bulletins the manufacturer has issued. “I am not going to discuss airworthiness directives,” he said, “or service bulletins.”
Doing that, he said, would lead to “speculation and rumor.”
The bomb threat received by Honolulu radio station KOHO was under investigation by the FBI. “A determination of whether it (the cause of the accident) was a bomb has not been made,” said bureau spokesman Harlan Frymire.
Danny Oshita, general manager of the Japanese-language station, said in an interview that an anonymous caller demanded the release of Osamu Maruoka, identified by Kyodo News Service as second in command of the Japanese Red Army.
Tel Aviv Airport Attack
In Tokyo, Japanese police said they arrested Maruoka on Nov. 24, 1987. They said he was wanted in connection with a bloody attack at Tel Aviv’s Lod Airport in 1972 and the hijacking of a jetliner over India in 1977.
The United accident recalled last April 28, when a flight attendant was killed and 61 people were injured as structural failure caused the roof to peel off an Aloha Airlines Boeing 737, also over Hawaii.
It exposed the first-class section to the open air at 24,000 feet. The attendant was blown out of the plane.
That Boeing aircraft was 19 years old and had made 79,000 takeoffs and landings.
Inspectors found tiny cracks in nearly half of Boeing’s aging 737 jets after the accident.
Then, in December, an Eastern Airlines Boeing 727 with 104 passengers and a crew of six was forced to land in Charleston, W. Va., after a 14-inch hole ripped in its fuselage.
That plane was at 31,000 feet when it tore open. No one was hurt.
More recently, Boeing confirmed that crossed tubes were found in fire-extinguisher systems in two Air Canada 767s. In all, more than 30 such cross-connecting problems in tubes and wires have been discovered over the past year.
Finally, some major airlines have criticized delays in the delivery of new Boeing 747s and say they will seek compensation for planes they will not receive on time.
Boeing has acknowledged the delays but says it is trying get back on track.
Times computer analyst Paul Orwig, staff writers Ralph Vartabedian, Doug Jehl, Ronald J. Ostrow and researcher Tracy Shryer also contributed to this report.
