Volume 11, Number 1 • Spring 2003 • Aerospace Technology Development

FAA and NASA Provide Turbulence-Warning Benchmarks

NASA and Federal Aviation Administration (FAA) researchers are working to estimate how long it takes to secure the passenger cabin of a wide-body airliner in advance of oncoming air turbulence following a three-day joint experiment at the FAA’s Mike Monroney Aeronautical Center in Oklahoma City. The Aircraft Cabin Turbulence Warning experiment last October provided critical information to improve in-flight safety for turbulence encounters, the largest cause of in-flight injuries.

Sponsored by the joint FAA-NASA Aviation Safety Program, tests were conducted by crews from three major air carriers — United, Delta and US Air. In addition, American Airlines, JetBlue Airways and Southwest Airlines supported the work with equipment and staff, and two flight attendant unions — the Association of Flight Attendants and the Association of Professional Flight Attendants — provided support through planning and technical consultation.

Experimenters used about 70 persons hired as test subjects in the Civil Aerospace Medical Institute’s (CAMI) Boeing 747 research craft on the Aeronautical Center’s ramp at Will Rogers World Airport, Oklahoma City. A team of human factors researchers from the FAA, NASA, industry and interested employee organizations conducted the tests at CAMI using several scenarios each day, including one alert during food and beverage service.

Test results will provide warning-time benchmarks for manufacturers and for aviation industry certification activities required before installation of new turbulence-detection equipment in operational aircraft. New technology developed with support from the Aviation Safety Program, one version of which is based on modified weather radar technology, has been recently demonstrated that provides more than one minute of encounter warning and a low false-alarm rate. Realistic warning-time estimates from this series of trials will provide useful guidance to these activities.

Preliminary results from the series of trials suggest that 95 percent of the passengers can return to their assigned seats and fasten their seatbelts within 95 seconds.

“Even with some time added for processing the warning and making an announcement to the cabin occupants, this result demonstrates that a large percentage of the passengers could be seated within the warning-time window provided by the radar technology,” said Rodney Bogue, Aviation Safety Program and turbulence technology Project Manager at NASA Dryden Flight Research Center at Edwards, CA.

“The aim here is to reduce passenger and crew injuries in turbulence encounters,” said Robert Shaftstall of the CAMI staff. “These results provide a valuable benchmark against which future developments will be measured.”

“The lack of a reliable turbulence warning has been one reason that commercial aircraft cabin crews have not been able to effectively prepare for turbulence encounters,” Bogue added. “Current turbulence-warning announcements and seatbelt advisories have a high false-alarm rate, and it is not surprising that passengers and flight attendants place little confidence on in-flight warnings. Quite often, they are out of their seats or in their seats without belts fastened when turbulence encounters occur.”

CAMI conducts human factors research for the FAA in all areas of aviation. CAMI’s Boeing 747 wide-body research vehicle is used for cabin evacuation testing, cabin airflow analysis and other studies. Q

For more information, contact Rodney Bogue, Staff Scientist at NASA Dryden Flight Research Center, Code RI, PO Box 273, Edwards, CA 93523, T: 661/276-3193, F: 661/276-2842. Please mention that you read about it in Innovation.

NASA Official: Jonathan Root • Web Design: Printing & Design Office, NASA Headquarters • Credits