Airline Passengers, Relax: Turbulence Detectors Are on the Way

John Roach
for National Geographic News
January 22, 2007
Wouldn't it be nice if airline pilots turned on the "fasten seat belt" sign before the person standing in the aisle toppled onto your lap because of turbulence?

NASA researchers are on the job. They are developing a pair of technologies that will give pilots several minutes' warning so they can steer clear of the erratic, gusty winds.

"That's enough time to get everybody seated and carts stowed if you're in the meal phase of the flight," said Jim Watson, an engineer at the NASA Langley Research Center in Hampton, Virginia.

"And it also allows you to contact air traffic control and get a route diversion if necessary," added Watson, who is project manager for NASA's Turbulence Prediction and Warning Systems.

The system's technologies aim to prevent injuries and save airlines millions of dollars.

Of the 58 turbulence-related injuries that occur on average in the United States each year, 98 percent happen because people don't have their seat belts fastened, according to the U.S. Federal Aviation Administration.

And turbulence costs airlines about a hundred million U.S. dollars a year in rerouted flights, late arrivals, and additional aircraft inspection and maintenance.

Turbulence Detection

The technologies were developed as part of a NASA program to predict oncoming turbulence and report its severity when encountered.

(Read related story: "New Icing Warning System for U.S. Airplanes Debuts" [December 6, 2006].)

One of the technologies is called Enhanced Turbulence, or E-Turb, Radar. It upgrades existing airborne weather radar systems so they can detect turbulence associated with thunderstorms.

E-Turb's software uses vertical and horizontal radar scans of the weather in front of the airplane to determine the severity of the turbulence.

The software takes into account how moisture is moving through the air—a measure of turbulence—as well as specifics about the airplane such as weight, speed, and angle of flight.

Since not all planes are created equal—a 747, for example, is much heavier than a Learjet—the same amount of turbulence will jostle different planes differently, Watson noted.

The hazard calculated by E-Turb is then presented to the pilot in an easy-to-read format.

"The pilot sees what is called a magenta display that essentially says, For this turbulence level you should get everybody in their seat, and for this higher level turbulence you should definitely get everybody in their seat, and you might want to try to avoid it," Watson said.

The system was tested for 18 months on a Delta Air Lines aircraft. The flight data collected during the test is currently under evaluation, and Watson's team plans to make recommendations this spring on whether the system should be deployed by other airlines.

(See National Geographic magazine's "The Future of Flying.")

Turbulence Reports

The second technology under development is called the Turbulence Auto Pilot Reporting System (TAPS).

This software kicks in when an aircraft's accelerometer, an instrument that measures acceleration, detects an encounter with turbulence. It immediately calculates the severity of the turbulence and reports that information to computers on the ground.

After the airplane lands, maintenance technicians can then use the information to determine if the aircraft warrants special inspection before it returns to the air.

Eventually engineers plan to rebroadcast the information to aircraft flying similar routes, so pilots will know where the turbulence lies, allowing them to take evasive action if necessary.

This is particularly useful in the 10 to 20 percent of turbulence events that occur in the absence of moisture and therefore evades radar detection, Watson said.

Currently TAPS is used on more than a hundred Delta aircraft. As of August 2, 2006, it had generated more than 76,000 turbulence reports, according to AeroTech Research, a Hampton, Virginia, firm working with NASA on the project

Tom Staigle is the chief technical pilot for Atlanta, Georgia-based Delta Air Lines. In a testimonial posted on AeroTech's Web site, he praises the potential of the combined turbulence technologies.

"Together with TAPS, the enhanced turbulence radar effort marks one of the most exciting developments in the struggle to deliver better quality turbulence hazard information to flight crews and potentially other aviation user groups," he said.

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