About Our Work: Turbulence Research
Aircraft in flight create wake turbulence. The most notable components of the wake turbulence are a pair of counter-rotating cylindrical air masses, called wake vortices, that result when aircraft generate lift. Wake vortices can be a potential hazard to following aircraft. In the absence of operational means to locate and track vortices, safety is currently maintained by imposing arrival and departure separations between aircraft in the terminal area. Because vortices can propagate while in ground effect, they can also be a potential hazard to parallel runway operations.
These considerations have imposed restrictions on potential capacity increases at the nation's high density airports. The requirement to maintain the vortex imposed separation standards impedes meeting the capacity demands at the major airports, and will be a restriction on meeting the projected capacity demands in the future. Since the present and predicted demands on airports cannot be met by constructing additional runways on existing airports or by constructing additional airports because of economic or environmental considerations, a better understanding of the wake vortex phenomenon and applying that understanding to the modification of separation standards may be the most effective method of obtaining additional airport capacity.
The overall objective of the Federal Aviation Administration (FAA) in conducting the Wake Vortex Program is to increase airport capacity and maintain or improve safety of operations.
The primary objective of the Volpe National Transportation Systems Center (Volpe Center) Wake Vortex Program is to assist the FAA in the development of systems and procedures capable of providing the air traffic control system with the information required to maximize traffic flow for existing vortex conditions such that more efficient air traffic management can be implemented in the terminal airspace. A requirement of any proposed systems or procedures is that implementation should not increase the controller or pilot workload.
A general summary of Volpe Center accomplishments during a long history of effort on the wake vortex problem include the following:
- Developed techniques for detecting and tracking vortices;
- Developed the Laser Doppler Velocimeter (LDV), the Monostatic Acoustic Vortex Sensing System (MAVSS), and the Ground Wind Vortex Sensing System (GWVSS);
- Conducted extensive test programs at Chicago's O'Hare International Airport, New York's John F, Kennedy International Airport, and other test sites, utilizing a variety of sensors to measure the behavior of vortices generated by arriving and departing aircraft;
- Measured and classified the vortices generated by rotorcraft.
More recent Volpe Center accomplishments are listed below:
- Set up GWVSS with unattended data collection system at Memphis Airport to support development of the National Aeronautics and Space Administration's (NASA) Aircraft Vortex Spacing System (AVOSS);
- Participated in a cooperative effort with NASA Langley at the FAA/Volpe Center Vortex Test Site at JFK International Airport to evaluate a number of potential wake vortex sensors;
- Developed a cooperative effort with National Oceanic and Atmospheric Administration for the acquisition, review, and analysis of the 1990 Idaho Falls tower fly-by vortex data;
- Conducted validation testing, using the Volpe Center GWVSS at JFK International Airport, to provide ground truth for the testing of a Radar Acoustic Sensing System for the detection of wake vortices;
- Maintained and operated the JFK GWVSS to obtain vortex transport data;
- Conducted testing at JFK International Airport to characterize jet blast profiles;
- Conducted testing at LaGuardia International Airport to resolve wake vortex related issues concerning crossing runway operations.
The Volpe Center will continue the analysis of data collected during previous vortex test activities and all outstanding reports will be issued. It will work toward the resolution of various existing operational issues at airports such as JFK International and LaGuardia and will develop test programs and conduct testing designed to increase capacity single runway, closely spaced parallel runway, and intersecting runways while maintaining the current level of safety. The Volpe Center will provide support to the FAA Wake Vortex Program Office such as assistance in program and planning activities. This work will be done in close cooperation with FAA, NASA Langley Research Center, and other government agencies and private industry.
The Aircraft Wake Vortices: An Annotated Bibliography is available.
