The Boeing 787 is sometimes called the ‘plastic plane’ due to its substantial use of carbon fiber, but it also pioneered greater use of electric systems.
At the heart of these developments was the 787’s electrical environmental control system (ECS), which replaced the traditional pneumatic bleed air control with electric motor-driven compressors that feed the rest of the ECS.
Prior to the 787, efficiencies for pneumatic systems were mainly achieved by making them lighter, but bleed air usage provided another avenue.
This is because it can be more efficient to generate pressurized air using an electric compressor, since the traditional bleed air system takes some of an engine’s energy that could be used for propulsion.
“With the arrival of ‘more electric’ aircraft, there is now a consideration between traditional pneumatic or a more electric function,” says Bill Dolan, VP engineering for UTC Aerospace Systems, which makes the 787’s ECS.
So, what is the future for traditional pneumatic systems? At present, they interact with a huge array of other systems and aerostructures--engines, pylons, slats, the APU, avionics and interiors, for example--so is it conceivable that electric systems could take over in all those cases?
“There will be some aircraft in the future for which it will make sense to fully replace pneumatic power by electrical power,” says Nicolas Bonleux, managing director and chief commercial officer for Liebherr-Aerospace & Transportation.
“This will depend on the aircraft’s configuration, on the propulsion technology and on the technology used by the other on-board systems. However, we are convinced that for other aircraft pneumatic power will remain the best suited technology.”
To find out more about the future of commercial aircraft pneumatics, see the next issue of Inside MRO.