As the Boeing 787 gets ready to enter service at All Nippon Airways (ANA) in September, Let’s take a look at this “more electric” aircraft.
Over the years, the demand for electrical power increases as new technologies such as fly-by-wire (FBW), digital avionics, and in-flight entertainment (IFE) systems are introduced. This is in addition to other power demand increases, such as the on-going change from hydraulic and pneumatic systems to electrically powered systems. When you look at 787, which is a replacement for a Boeing 767-sized aircraft, it’s amazing to see that it will generate five times the electrical power than its predecessor!
When Boeing started designing the 787, they decided to depart from the traditional architecture and go with a “no-bleed” design. Boeing claims that the new system would provide improved fuel consumption, reduced maintenance costs, improved reliability, and reduced number of components
Boeing achieved this by removing bleed air extraction from the engine (making it more efficient!), and instead driving the environmental control system (ECS) and anti-ice system electrically. Boeing also removed air turbines that traditionally drive part of the hydraulic system, so the hydraulic system is all electrically driven. Finally the auxiliary power units (APUs) on the 787 provide only electricity, as opposed to pneumatic and electrical power from other APU’s.
It is interesting to note that when Airbus launched the A350 XWB, they decided not to follow suit and retained the more conventional bleed architecture. Did Boeing make the right decision by adopting the no-bleed system, or did Airbus make the right move by staying with the current system? Given that both Airbus and Boeing have decided to re-engine rather than design a new narrowbody aircraft, we will have to wait to see the verdict.
For more details, you can take a look at this article form Boeing.