Revised Wake Turbulence Categories Increase Airport Capacity
Since adopting new standards of categorizing aircraft for their wake turbulence, Memphis International Airport has increased its operational capacity by an estimated 15 percent. Under a new FAA system called Recat (for “re-categorization”), the new standards refine how aircraft wake turbulence levels are categorized. This makes for significant differences in determining following distances on landing and wait times for aircraft taking off after the aircraft ahead.
The old standards divided aircraft into five categories based primarily on weight. The new program has six categories, based not only on weight, but also on approach speed, wing design and other factors. The new categories are labeled A – F, with A generating the most severe wake turbulence. The Airbus A380 is in the A category, while small jets such as Cessna Citations are listed in the F category.
For example, at Memphis, FedEx MD11s, Boeing 767s and Airbus A320s are all in the C category. As such, inline separation on approach for such aircraft has been reduced from four miles to 2.5 nm. Takeoff wait times are reduced by as much as five minutes, depending on wind and runway conditions, saving time and reducing fuel burn and emissions.
The Recat program resulted from 10 years of study by the FAA, the DOT/Volpe National Transportation System Center, Eurocontrol and private industry. It is expected to be adopted at more airports over the next two years, with an estimated average increase of 7 percent in operational efficiency.