NATIONAL COALITION OF SCHOOL BUS SAFETY NEWS 2007

Engineer Reports on Bus Accident
February 22, 2007

An engineer's report to the Bradford Area School District indicates corrosion and poor quality material on a U-Bolt were the reasons an axle fell off a moving school bus in December.

The report describes what Superintendent Sandra Romanowski reported to The Era on Jan. 31 in a more detailed, technical version and confirms her report there was no sabotage to the axle as previously rumored.

On Dec. 4, the school bus was carrying 36 children when the axle fell off. Two children were injured and taken to Bradford Regional Medical Center following the incident on Bolivar Drive. The children were students from both School and George G. Blaisdell elementary schools.

One child had a bruised ankle and the other a broken ankle, officials said.

The report, in letter form, is addressed to David Bizzak of Romualdi, Davidson & Associates Inc., a workman's compensation group. District Business Manager Kathy Kelly said that group, along with Laidlaw Transportation Management Systems, went to RJ Lee Group Inc., to put together the report.

"Specifically, the failure was a single-event brittle fracture that initiated at either a small corrosion pit or a fatigue crack," reads the report.

The letter explains "the fracture surface was examined optically and by scanning electron microscopy/energy dispersive spectroscopy techniques."

It continues that a small rust thumbnail was seen and appears to be the fracture initiation site. "The failure appears to have been a single event brittle fracture originating at the rusty thumbnail," the report states.

"Except for the small thumbnail rust region associated with a corrosion pit that may be a small fatigue crack and was the initiation site, the fracture propagated as a single-event, brittle cleavage fracture."

The investigation revealed the failure was due to the conjoint interaction of a small corrosion pit or fatigue crack with a material that exhibited inadequate toughness for the application.

"... The failure appears to be the result of low material toughness and corrosion."

MERRILL GONZALEZ, Era Reporter

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