Wake turbulence forms behind an aircraft as it
passes through the air. In certain cases, the
wake turbulence generated by large aircraft can
be hazardous for aircraft passing behind. This
turbulence has been known to cause smaller
planes to roll or flip over without warning.
The FAA previously used five wake turbulence
separation categories based primarily on
aircraft weight. The RECAT initiative resulted
in six categories, based on weight, approach
speeds, and wing characteristics. The categories
are labeled A to F, with Category A including
very large aircraft such as the Airbus A380 and
Category F including smaller planes such as the
Cessna Citation and Embraer 120.
FedEx is the largest carrier at Memphis, with
about 500 operations a day. Most FedEx aircraft
are in Category C, including the MD-11, B767,
and A300 series aircraft. Because they are in
the same category, these aircraft can now be
separated by 2.5 to three nautical miles instead
of the previously required four nautical miles.
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