Two recent fatal midairs have shown the limitations of the “see and avoid” concept of aircraft separation, including human error, environmental conditions, blind spots and operational distractions, according to an NTSB analysis. Consequently, the Board has issued a Safety Alert that describes operational methods and the use of in-cockpit technology to compensate for these limitations. Errors by ATC resulted in the pilots’ inability to take action to avoid the collisions, it said.
On July 7, 2015, a Cessna 150 and a U.S. Air Force F-16 collided. The two occupants of the Cessna were killed; the F-16 pilot ejected. A controller advised the F-16 pilot that the Cessna was a potential traffic conflict, but he was not able to visually acquire the Cessna until it was too late to avoid the collision. The NTSB determined that the probable cause of the crash was the controller’s failure to provide an appropriate resolution to the traffic conflict.
On Aug. 6, 2015, a North American Rockwell Sabreliner and a Cessna 172 collided. The four occupants of the Sabreliner and the sole occupant of the Cessna were killed. A cockpit visibility study revealed the fields of view of both pilots were limited and partially obscured at times. The Safety Board determined that the probable cause of the accident was the controller’s failure to properly identify the Cessna and to ensure instructions were being followed before turning the Sabreliner into the Cessna’s path.
In addition to issuing the Safety Alert, the NTSB made recommendations to the FAA and the companies operating federal contract control towers asking them to brief controllers on the errors in the two midairs and to include these accidents as examples in training.