Jet Blowout Cause Narrowing to Door : Investigators See No Signs of Bomb; Ocean Searched for Victims, Debris

HONOLULU —  Investigators trying to discover what ripped a truck-sized hole in the side of a United Airlines Boeing 747 near Hawaii said late Saturday they could find no evidence of a bomb. They reported that the accident, which killed nine passengers, could have been caused by a cargo door which gave way because of air pressure inside the plane.

Michael Marx, senior metallurgist for the National Transportation Safety Board, said, however, that there was no indication of any extraordinary pressure or weight load on the cargo door.

When asked why the door gave way, Marx replied: “Did you ever bust a balloon” by blowing it up over and over again?

He declined to be more specific.

Marx said there were no signs of metal fatigue or corrosion on cargo door locks that were still on the plane. But he would say nothing about whether there was an indication that any latches failed.

Pacific Crisscrossed

As investigators pored over the aircraft, searchers crisscrossed the Pacific Ocean looking for survivors. “You know, a normal human being just can’t last that long, even in 70-degree waters--plus they fell 22,000 feet,” Coast Guard spokesman Keith Spanger said. If anyone lived through the fall, Spangler said, chances for survival were slim.

He said the sea was infested with sharks.

At least one of the victims was sucked into the whirling blades of a jet engine. The blades were bent, and a medical examiner found “multiple small body parts” inside.

More than 30 investigators, headed by Lee Dickinson, a member of the NTSB, swarmed through the plane trying to discover why a cargo door and part of the fuselage came apart early Friday as the aircraft climbed up and away from Honolulu International Airport and turned toward Aukland, New Zealand, carrying 357 people.

A hundred miles south of Hawaii, the door and a section of metal above it tore out of the fuselage and the jumbo jet decompressed. In addition to the passengers who were sucked out, 27 others, including several crew members, were hurt by flying debris. Two engines failed, and pilot David Cronin returned and landed the jet like a lead sled--hard but safely.

It was the third in a recent series of structural failures on Boeing planes. Last April, the top of a 737 peeled off during an Aloha Airlines flight from Hilo to Honolulu, killing an attendant and hurting 61 others. In December, an Eastern Airlines 727 was forced down in West Virginia after a 14-inch hole opened its fuselage. Nobody was hurt.

Dickinson said his team would investigate every possibility to determine the cause of the latest accident. “All doors are completely wide open,” he added.

But he said his experts would pay particular attention to the cargo door and its locking mechanisms--and the aircraft cargo area. By nightfall Saturday, the Coast Guard had not recovered the door, and Dickinson said the chances of finding it diminish with each passing hour. He said the door was one thing investigators would especially like to see.

Last year, the Federal Aviation Administration called the attention of airlines operating 747s to an instance in which a cargo door opened partially in flight. It said this could “result in rapid decompression of the airplane.” The FAA ordered the airlines to reinforce cargo door locks with steel plates.

The agency gave the airlines until next Dec. 31 to complete the modification.

Modification Not Made

When asked whether locks 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.”

Reporters were taken to within 100 feet of the plane. It was clear that its cargo door, hinged at the top, had lifted cleanly from the bottom of its aperture and had been torn off the airplane--hinge and all--taking part of the fuselage with it and ripping a jagged edge along the upper part of the hole it left behind.

Strips of metal aircraft skin had been peeled away and were hanging from the top of the hole.

Through the hole, the passenger floor was clearly visible. Some seats were still attached.

The cabin ceiling had fallen and parts that were not sucked out still filled the aisles with debris.

Other members of Dickinson’s team will talk to flight crew members, including Cronin, a 34-year veteran pilot whom United hailed as a hero for bringing the severely damaged jet and its 348 remaining occupants down safely.

Despite its damage and the lack of power from two of its four engines, Cronin landed the aircraft with nothing more than a hard jolt--and some ruptured tires.

The first officer was G. A. (Al) Slater. R. M. (Mark) Thomas was the second officer. All three men are based in the Los Angeles area.

The flight had 15 attendants, credited by passengers with maintaining calm on the plane. The attendants are based in Honolulu.

Some investigators have been assigned to document survival factors: the type, severity and cause of the injuries suffered; how the cabin flew apart, and rescue efforts on the ground. Still others will study the plane’s maintenance records. Others will check its engines. And another group will review the contents of its cockpit voice and flight data recorders.

Dickinson said neither he nor any members of his team will try to offer any explanation shedding light on the accident for several weeks. “We will not be making any causal determinations while we are here on scene . . . “ he said. “But (eventually) we will figure out what happened and why.”

Other aviation experts also were focusing attention on the cargo door, its locks and surrounding structure. Although representatives of Pratt & Whitney, which made the engines on the jet, are aiding the investigation, experts say its two engine failures are probably the result of foreign-object ingestion from the fuselage blowout.

It is unlikely, these experts said, that the engine failures caused the accident.

The FBI also was assisting in the investigation.

Special Agent Harlan Frymire said the bureau was looking into “several calls claiming responsibility” for the disaster.

But he said such calls are typical after a spectacular incident.

None of the calls “dovetailed” with other information authorities had, Frymire said.

Interviews Completed

He said agents had finished interviewing all passengers, crew members and other airline employes with access to the plane--such as baggage handlers--and had found “no irregularities.”

No one who was supposed to have boarded Flight 811 in Honolulu failed to do so and hence might be responsible for bombing the plane, he said.

However, he added: “We still consider the cause to be undetermined.”

Meanwhile, the Navy and Coast Guard almost doubled their search area to cover 3,000 square miles of the Pacific.

A Coast Guard cutter recovered “what appeared to be part of the fuselage” Friday night, spokesman Spangler said. The 4-by-6-foot piece of metal was turned over to investigators, along with several smaller pieces of debris. A Navy helicopter reported spotting what appeared to be a luggage rack Saturday morning.

Spangler said most of the debris was spotted in water 88 miles south-southwest of Honolulu Harbor.

“Anything that’s floating, we’re picking up,” he said.

Searchers speculated that large pieces of debris probably sank in the 15,000-foot-deep ocean.

Spangler said three helicopters, two planes and four vessels would continue combing the sea until nightfall, then decide whether to resume at daybreak.

Hospitals in Honolulu reported treating 27 people, mostly for minor injuries. Five remained hospitalized Saturday.

After leaving the plane, 200 passengers boarded other flights. Those who did not want to continue were put up in hotels.

United towed the damaged 747 to Hickam Air Force Base, adjacent to Honolulu International Airport, and concealed it from public view.

The jumbo jet is 18 years and three months old. After 20 years of service, Boeing says, its jets need increased inspections and repairs because they crack more frequently.

Here, compiled by the Associated Press, are recent incidents involving airliner aging and metal fatigue:

--Jan. 20, 1989. A Piedmont Airlines 737 dropped an engine shortly after takeoff from Chicago. None of three passengers and crew were injured and the plane landed safely. The aircraft was seven years old, but authorities blamed metal fatigue and a cracked bolt.

--Sept. 21, 1988. An American Airlines 727 made a belly landing at Dallas-Ft. Worth after metal fatigue in its landing gear prevented the pilot from opening the wheel well door. The 88 passengers and crew evacuated with three people injured. Boeing had recommended inspections eight days earlier after finding metal fatigue in the same area in other 727s.

--May 9, 1988. A 20-year-old American Airlines 727 was forced to make an unscheduled landing at Detroit after a 15-inch crack in a wheel well caused a drop in cabin pressure. Staff writers Tamara Jones, Patt Morrison and Ron Harris in Hawaii contributed to this story.