sentences:  Further contributing to the accident was inadequate communication between ATC and the N600XL flight crew.CENIPA and the NTSB collaborated in the accident investigation and, while agreeing on most of the basic facts and findings, the two organizations arrived at conflicting interpretations and conclusions.The CENIPA report concluded that the accident was caused by mistakes made both by ATC and by the ExcelAire pilots, whereas the NTSB report focused on the controllers and the ATC system, concluding that both flight crews acted properly but were placed on a collision course by the air traffic controllers.