MICHAEL PHELAN / LONDON
System based on acoustic signatures is aimed at allowing controllers to visualize turbulence and improve safety
NASA's Langley Research Center is testing a system to measure the acoustic signature of wake vortices at Denver International Airport, which it hopes will allow controllers to visualise wake turbulence to increase safety.
Researchers are to spend three weeks collecting acoustic data at Denver using precisely calibrated microphone arrays to measure sound generated by aircraft vortices. Two lidar laser radars record the position, track and vortex strength, enabling engineers to classify subtle characteristics within the wake's acoustic signal.
Wayne Bryant, Langley wake vortex projects manager, says the test is aimed at acquiring the best data ever collected on wake acoustic phenomena, and to prove the feasibility of an acoustic-based detection system in an airport environment.
"One of the key items we will be looking for is a relationship between the recorded acoustic signal and the hazard the wake represents. Estimates of this hazard level will be provided by the lidar systems in our test," he says.
The Denver test will also provide an opportunity to evaluate recent modifications to a laser-based wake acoustic sensor being developed by Flight Safety Technologies and Lockheed Martin. The sensors for characterising ring-eddy atmospheric turbulence emanating sound (SOCRATES) projects low-power laser beams across open space on to a reflector device. Changes in the laser beams reflected reveal the existence of sound.
Vortex detectors, such as lidar or acoustic sensors, are envisioned as important parts of a wake vortex avoidance system designed to give pilots and controllers advance warning of the location and nature of hazardous wake turbulence. The technology could also allow reduced aircraft separation due to the ability to pinpoint wake location and decay rate.
Source: Flight International
