The following transportation safety issue was previously on the NTSB’s Most Wanted List. As a result of the actions taken to implement the necessary life-saving safety recommendations…We are Safer.
Between 1983 and 1993, there were at least 51 accidents and incidents in the United States that resulted from probable encounters with wake vortices. In these 51 encounters, 27 people were killed, 8 were seriously injured, and 40 airplanes were substantially damaged or destroyed. The NTSB conducted a special investigation to examine in detail 5 events to determine what improvements were needed to reduce the likelihood of wake vortex encounters. The investigation raised the following concerns about the adequacy of: (1) the current aircraft weight classification scheme to establish separation criteria to avoid wake vortex encounters, (2) air traffic control procedures related to visual approaches and VFR operations behind heavier airplanes, and (3) pilot knowledge related to the avoidance of wake vortices.
In 1995, the Board added two safety recommendations from the special investigation to the Most Wanted List, asking the FAA to revise the airplane weight classification scheme and to establish appropriate separation distances and to address air traffic control and operational procedures for heavier large category airplanes. The FAA conducted a study in conjunction with NASA on wake vortex turbulence, which led the FAA to revise and increase the separation and weight standards for aircraft. During the same time period, the FAA revised the Aeronautical Information Manual, which outlined procedures to help pilots make flight path adjustments to avoid serious wake vortex turbulence. These safety improvements led to removal of the issue area from the list in 1998.