Abstract: At approximately 9:20 a.m. on July 16, 1997, Employee #1 and coworkers, of the Boeing Company, were setting up loading spars at Building 54. Employee #1 was working on the first level of the assembly jig, setting up a wing box accept the spars for a new wing. Two coworkers on the second or third floor were pushing in a #4 contour board when an approximately 22 lb tool detail (#17N6W0604-402AJ; #1-AD28) fell from the board, bounced against various portions of the assembly, and struck Employee #1 on the head. He was rendered unconscious and sustained a laceration to his scalp that required approximately 20 sutures to close. The were several causal factors to this accident. The tool detail was not fastened properly to the contour board, it had only a thin cable to keep it from falling in case it became loose, and it was not maintained in safe operating condition. In addition, the employees did not have appropriate head protection even though there was the possibility of objects falling from above.