[Cboldt]

My guess is that any triple redundancy is limited to safty critical functions (flight control surfaces, primarily), and that many systems are not redundant at all (in-flight entertainment).

The powerplants aren't triple redundant, there are two engines. The aircraft can fly with one.

The triple redundncy relates to the fly-by-wire system:

The flight control system for the Boeing 777 airplane is a Fly-By-Wire (FBW) system. The FBW system must meet extremely high levels of functional integrity and availability. The heart of the FBW concept is the use of triple redundancy for all hardware resources: computing system, airplane electrical power, hydraulic power and communication path. The Primary Flight Computer (PFC) is the central computation element of the FBW system. The triple modular redundancy (TMR) concept also applies to the PFC architectural design. Further, the N-version dissimilarity issue is integrated to the TMR concept. The PFCs consist of three similar channels (of the same part number), and each channel contains three dissimilar computation lanes. The 777 program design is to select the ARINC 629 bus as the communication media for the FBW

Aerospace Applications Conference, 1996. Proceedings., 1996 IEEE (Volume:1)

[rodguy911]

Thanks very much. I really dont understand the significance of triple redundancy just thoght it looked relevant and I would pass it along to someone who actually knows what they are posting about which is not me.