Large Engine Uncontained Debris Analysis
DOT/FAA/AR-99/11
http://www.tc.faa.gov/its/worldpac/techrpt/AR99-11.pdf
Section 4.1.2, page 38 onwards
In a typical fan blade failure event where a large (> 50%) section of the blade is released, the blade tip section fragments and slides forward resulting in a helical trajectory while the root section of the blade is caught by the trailing blade and swept aft.
Much more information besides...