![]() As a consequence of this reduction in complexity, airlines will experience reduced airplane-level maintenance costs and improved airplane-level dispatch reliability. Overall, the 787 will reduce mechanical systems complexity by more than 50 percent compared to a 767 elimination of pneumatic systems is a major contributor. Ability to eliminate scheduled visual brake wear inspectionsīecause the 787 brakes can monitor the braking force applied even while parked, the electric brakes enable extended parking brake times by monitoring and automatically adjusting its parking brakes as the brakes cool.Īt an airplane level, the reduction in systems parts by moving to a primarily electric architecture is significant.Continuous onboard monitoring of the brakes provides airlines with a number of advantages, such as: In general, electric systems are much easier to monitor for health and system status than hydraulic or pneumatic systems the brakes take full advantage of this. The EBA is line-replaceable enabling in-situ maintenance of the brakes. Because its electric brake systems are modular (four independent brake actuators per wheel), the 787 will be able to dispatch with one electric brake actuator (EBA) inoperative per wheel and will have significantly reduced performance penalties compared with dispatch of a hydraulic brake system with a failure present. Electric brakes significantly reduce the mechanical complexity of the braking system and eliminate the potential for delays associated with leaking brake hydraulic fluid, leaking valves, and other hydraulic failures. Electric brakes significantly reduce the mechanical complexity of the braking system and eliminate the potential for delays associated with leaking brake hydraulic fluid, leaking valves, and other hydraulic failures.One innovative application of the more-electric systems architecture on the 787 is the move from hydraulically actuated brakes to electric. One innovative application is the move from hydraulically actuated brakes to electric. When compared to the more complex 767 IDG, the 787 starter generator is predicted to have a mean time between faults (MTBF) of 30,000 flight hours - a 300 percent reliability improvement compared to its in-service counterpart.īrakes. In addition, by using the engine generator as the starter motor (an approach used with great success on the Next-G eneration 737 APU), the 787 has been able to eliminate the pneumatic starter from the engine. This change enables elimination of the constant speed drive (also known as the integrated drive generator, IDG), greatly reducing the complexity of the generator. Another fundamental architectural change on the 787 is the use of variable frequency electrical power and the integration of the engine generator and starter functions into a single unit. In terms of inflight start reliability, the 787 APU is expected to be approximately four times more reliable than conventional APU s with a pneumatic load compressor.Įlectrical power generation. The use of starter generators reduces maintenance requirements and increases reliability due to the simpler design and lower parts count. Replacing the pneumatic load compressor with starter generators results in significantly improved start reliability and power availability. One of the primary functions of a conventional APU is driving a large pneumatic load compressor. ![]() The APU provides an excellent illustration of the benefits of the more electric architecture. Various ducts, valves, and air control systemsĪuxiliary power unit.The list below highlights just a few of the components eliminated as a result of this systems change: Overall, the 787 will reduce mechanical systems complexity by more than 50 percent compared to a 767 the elimination of pneumatic systems is a major contributor. By eliminating the pneumatic systems from the airplane, the 787 will realize a notable reduction in the mechanical complexity of airplane systems. While much can be said regarding the efficiency gains achieved by changing the means of extracting power for airplane systems from the engines, the 787’s no-bleed architecture brings with it some significant maintenance cost and reliability advantages as well. The only remaining bleed system on the 787 is the anti-ice system for the engine inlets. The transition from bleed-air power to an electric architecture reduces the mechanical complexity of the 787. PNEUMATIC COMPONENTS REMOVED FROM THE AIRFRAME: PNEUMATIC COMPONENTS REMOVED FROM THE ENGINE AND APU: Virtually everything that has traditionally been powered by bleed-air from the engines has been transitioned to an electric architecture. The Boeing 787 reflects a completely new approach to onboard systems. NO-BLEED, MORE ELECTRIC SYSTEMS ARCHITECTURE
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