Flight 232: A Story of Disaster and Survival (54 page)

Once investigators determined that the titanium fan was missing, Colonel Dennis Swanstrom, the base commander (center, in uniform), convened a meeting to try to formulate a plan for finding it.

The search for the missing fan failed. The fractured parts were found by accident during the harvest. The pieces were moved to the black security room, known as Cell 10, at General Electric in Evendale, Ohio. Analysis of the metal began immediately and went on all night and into the following days.
Photo Courtesy of GE Aviation, US

The defect that caused the fan to fracture was found on the inside of the hole, known as the bore, in the center of the disk. To the left of the numbers
51406
, the shape of the cross section can be seen where the disk was cut for examination. That shape is shown below.
Photo Courtesy of GE Aviation, US

The fan disk was cut from bore to rim to expose the defect, shown at the arrow labeled
01
. (See cut fan disk above.)
From NTSB Docket 437

Technicians used an electron microscope to identify smears of titanium metal at the locations where the stainless-steel hydraulic lines had been punctured. The evidence proved that parts of the fan had cut the lines.
From NTSB Docket 437

Two spectral plots produced with an electron microscope. The lower spectrum shows the stainless steel that the hydraulic lines are made of, which is mostly iron (FE). The upper spectrum shows the smear from the impact of a fragment of titanium (TI).
From NTSB Docket 437

The team of analysts zeroed in on the defect that started the cascade of failures that ended in the crash. The right side of figure 16 shows a normal matrix of titanium, aluminum, and vanadium in a proper alloy. The arrow, in the upper left, shows how the mixture, contaminated with nitrogen, fused together into “hard alpha” during manufacture and then cracked. Figure 17 shows a higher magnification of the same area. It was conclusive: the sequence that led to the crash began with defective titanium.
From NTSB Docket 437

Back row: Donna McGrady, Bill Records, Tim Owens. Middle row: Kathy Shen, Georgeann del Castillo, Barbara Gillaspie, Dennis Fitch, Jan Brown. Front row: Susan White, Al Haynes, Dudley Dvorak, Jan Murray.
Photo from the collection of Jan Brown

During a visit to the Sioux City Airport in 2012, Dennis Swanstrom (pointing), former base commander, recalls the events of 1989 with Jim Walker (center) and Lawrence Harrington (right). Walker, an Air National Guard pilot who volunteered on the scene, was one of the first people to respond.
Photo from the author’s collection

Cynthia Muncey wrote this postcard to her sister, Pam, shortly before boarding a plane in Hawaii that would take her to her connection with United Flight 232 in Denver.
From the collection of Pamela McDowell