Meggitt Safety Systems has developed a new bleed air leak detection (BALD) system for jet engines, and is to install the device on the General Electric CF6-80C2s that will power the US Air Force's re-engined Lockheed Martin C-5s.
The system consists of continuous loops of sensing wires close to bleed-air and auxiliary power unit ducts that can alert the crew to potentially structurally hazardous hot-gas leaks. The BALD system's loops comprise a sealed 2mm (0.08in) thick conducting wire surrounded by a temperature- sensitive ionic compound.
When exposed to heat, chemical changes in the cable allow the control unit to pinpoint the position of discrete leaks to within 25mm. Wide area coverage can be achieved by linking cables together to lengths of 30m, and Meggitt says the rugged material is resistant to bending and denting.
The BALD system is also being installed on the Aermacchi M346 trainer's two Honeywell F124-200 turbofans.
Source: Flight International
