Sensors monitor white-hot aircraft brakes
September 11, 2000
RICHLAND, Wash. –
"Too hot to handle" is no mere cliché for Air Force pilots and ground crews when an F-16 comes in for a landing. Heavy braking stops the plane in time but can produce high temperatures that risk rupturing tires or igniting fuel during refueling for quick turnaround missions.
Early warning of such risks soon will be possible with a sensor system under development at the Department of Energy's Pacific Northwest National Laboratory. The prototype sensor system will allow ground crews to measure an F-16's brake temperature as it lands and help the crew and pilot prepare for the worst if brakes approach 1,800 degrees Fahrenheit, which could produce a hot brake emergency.
"Pilots need to know the level of risk they face during a landing so they can determine if they should taxi away from other aircraft," said Jim Skorpik, Pacific Northwest chief engineer. "And once a fighter plane is safely down, if ground crews need to refuel for the next mission, they can check the sensor system to see if the brakes have cooled sufficiently."
The sensor system addresses these risks by coupling a temperature sensor that can detect temperatures up to 2,000 degrees Fahrenheit with a radio-frequency tag. The sensor will be inserted into an existing wear pin the size of a large nail that is used to monitor brake pad wear on the F-16. The accompanying wheel-mounted RF tag is comprised of a tiny silicon chip and an antenna connected to the sensor by an industrial cable.
When the plane lands, ground crews will use a wireless hand-held device called an interrogator that beams radio waves to the RF tag from up to 100 feet away. The radio waves activate the RF tag, which collects a temperature reading from the sensor. Then the RF tag sends that information back to the interrogator. Also, the device can read information from numerous tags simultaneously.
The military has been examining greater safety systems as new weapons systems and fuel pods for greater range have caused the F-16 aircraft's weight to increase. The added weight can mean pilots need to brake harder to stop in the same amount of runway distance.
Pacific Northwest engineers have ground tested the sensor system to ensure the wheel-mounted tag can communicate with the interrogator. Tests were conducted with support of the 388th Fighter Wing stationed at Hill Air Force Base near Ogden, Utah, http://www.hill.af.mil/. Pacific Northwest engineers expect to conduct additional tests of the prototype system this fall.
The $20 million F-16 Fighting Falcon first flew in 1976 and is used by NATO countries. The F-16 participated in more Operation Desert Storm missions than any other aircraft and was integral to the success of the 1999 Operation Allied Force missions over Kosovo. The U.S. military's current fleet of 1,500 is expected to remain active until 2020.
Pacific Northwest engineers have developed RF tags for nearly 10 years for inventory control of items such as designer clothing and military night vision goggles. For more information on Pacific Northwest's RF tag development, go to http://www.pnl.gov/nsd/commercial/rftags/. Business inquiries on this or other Pacific Northwest technologies should be directed to 1-888-375-PNNL or e-mail: firstname.lastname@example.org.
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