The investigation board on Friday has blamed maintenance department for the crash of PK661 in Havelian. Media has obtained the initial investigation report, according to which, the plane lost its power turbine blade during the flight that jammed one engine. The report revealed that it was necessary to change the turbine blades after 10,000 hours but the department did not replace them. PIA should immediately hold audit of the department, it further suggested. The report also recommended PIA to strictly follow the rules regarding planes maintenance and to take proper action to avoid such incidents in future.