A new air data sensor technology that does not require internal heating to avoid icing could be ready for commercial service in five years, says United Technologies Aerospace Systems (UTAS).
An agreement announced by UTAS on 5 July commmits the Charlotte-based systems supplier to help Ophir Corp develop and commercialise a laser air data system (LADS) for commercial aircraft.
The laser-based system uses a phenomenon known as Rayleigh scattering – in which photons interact with molecules smaller than light – to determine the aircraft’s velocity, angle of attack, angle of sideslip and altitude, UTAS tells FlightGlobal in an email.
The same information is collected on aircraft now by using pitot probes that extend out from the fuselage, but the devices must be heated to prevent icing. The probes, which use pneumatic pressure to measure the same parameters, also slightly reduce the aircraft’s fuel efficiency by increasing aerodynamic drag.
UTAS envisions a combined air data system that uses both pitot probes and lasers on the same aircraft to cross-check air data readings.
Although the system depends on lasers, using the Rayleigh approach means “there will always be scattering avavilable at all altitudes and in all flight conditions,” UTAS says in an email. “This technology is designed to focus relatively close to the aircraft skin, so optical losses due to the presence of airborne particles (aerosols, smoke, water, droplets from clouds, ice crystals, etc) are minimal.”
Flight data data shows that air data measurements and update rates by LADS “compares well” against pitot probe systems, but there is a catch.
“As is often the case with emerging technologies, the initial cost of the optical system may be higher than traditional air data systems,” UTAS says. But costs should decline as production volume grows. Meanwhile, a combined laser-pitot air data system “will offer a differentiated value proposition to aircraft manufacturers”, UTAS adds.