The NTSB, which participated in the investigation into the September 2006 midair between a Gol Airlines Boeing 737-800 and an ExcelAire-owned Embraer Legacy 600, authored an appendix to the final accident report issued yesterday by Cenipa, Brazil’s safety agency. All 154 aboard the 737 were killed in the accident, while the damaged Legacy successfully made an emergency landing. Although the NTSB does not disagree with the report’s factual determinations, it said “interpretations, conclusions and understandings of the relationship between certain factual items and the demonstrated risk differ in a number of respects.” Notably, the NTSB appendix focuses on “how the primary mission of ATC to separate aircraft within positive controlled airspace was unsuccessful.” The NTSB maintains that Cenipa’s conclusions don’t adequately reflect deficiencies acknowledged in the body of the report, including “a lack of timely ATC action” after the Legacy’s loss of transponder and two-way radio communication and “features of the ATC software that may have aggravated deficiencies in altitude clearance awareness.” The NTSB appendix three times points out that there is “no evidence of regulatory violations” by the Legacy’s crew. Joel Weiss, lawyer for U.S. Legacy pilots Joe Lepore and Jan Paladino, said, “The Cenipa report hides the real and obvious cause of this tragic accident. ATC placed these two competent flight crews on a collision course, traveling toward each other at the same altitude on the same airway. It also buries the fact that this was not only a result of major errors by individual air traffic controllers, but of institutional errors built into Brazil’s ATC system.”