The reason is technology obsolescence , says Chuck Royalty
, lead engineer for network systems with Boeing's
777 program.The 100-megabits/sec ( Mbits/sec ) optical system links maintenance terminals with the central maintenance function in the Aircraft Information Management System.The original maintenance network also included links using 10-Mbit/sec Ethernet.
For a system that uses glass fiber and electromechanical components in a severe environment , the B777's FDDI has a reputation for reliability.I am aware of maybe one [ optical fiber ] break because a cable was bent , Royalty
, a longtime FDDI user , considers the bus very reliable in service..
But now the technology is becoming more expensive and less available , Royalty
says.Boeing plans to replace the optical system with 10-Mbit/s , copper Ethernet , concurrent with its implementation of an AIMS-2 upgrade on the B777-300ER and 777-200LR airplanes , expected in the third quarter of 2003 and the first quarter of 2004 , respectively.Instead of being part FDDI and part Ethernet , the maintenance network will now be all-Ethernet , Royalty
predicts that the replacement , all-Ethernet system will be a wash –comparable in maintainability and reliability to the optical system.
Civil aviation appears to be moving toward faster Ethernet technology.Boeing
already employs a 10-Mbits/sec Ethernet network on the 767-400ER aircraft for flight-critical displays.And Airbus plans to deploy a 10-Mbits/sec/100-Mbits/sec , full-duplex , switched Ethernet communications system on the A380 super jumbo aircraft.ARINC's Ethernet standardization effort can be found in Project Paper 664 , including both 10 Base-T and 100 Base-T implementations.No date has been set for the completion of that work.