Guy Norris / Seattle
Boeing and FedEx Express plan a 120-day evaluation of active radio-frequency identification (RFID) tag technology on an MD-10 that will enable data from the aircraft’s systems and structure to be continuously monitored and broadcast.
The system, which builds on earlier tests of passive RFID technology, will provide “a platform to do a true integrated vehicle health monitoring system”, says Boeing RFID project leader Kent Porad. “Instead of sensors being hardwired through the various databuses, we will be able to proliferate them around the aircraft, gather the information and send signals to the ground using a system such as Connexion by Boeing.”
The active RFIDs under test have a sealed lithium battery that enables them to broadcast signals with a range of up to 100m (330ft). The battery life on these early units is expected to be only six to 10 years, but Porad says research is under way on micro-battery technology with a life of up to 20 years. “When the power goes out, it defaults to become a passive sensor,” he adds. Built by Intelleflex, the tags have an in-built antenna and a 64kb-capacity rewritable memory.
Passive RFIDs will be standard on the 787. Some 2,100 of these passive “backscatter” tags will be installed on about 700 unique parts on each aircraft. Each tag will record 19 data elements on delivery, including part and serial number, date and place of manufacture, production lot number, weight, nomenclature and electrostatic sensitivity.
The passive tags, which have no battery, send out radio signals on frequencies between 860MHz and 960MHz using reflected energy from a handheld device similar to a barcode reader. “For example, when the maintenance crew is checking the [emergency] oxygen bottles on the 787, they won’t need to physically open every passenger service unit to inspect them,” says Porad. “They will just go through the cabin and read the data from the radio waves sent back by the tags.
“The tags will be 100% accurate as a way of recording the configuration as delivered. The system will therefore help keep track of configuration changes over the life of the aircraft. This is the new system architecture. We’ve agreed with Airbus, Bombardier and Embraer on what we’re all doing. After all, Airbus and Boeing share 70% of the same suppliers,” he says.
Adoption of passive tags on the 787 follows two service evaluations on a FedEx MD-10 in which devices were attached to line-replaceable units located in spots such as the wheelwell and cargo compartment. “They flew for a year and had zero failures,” says Porad. The last evaluation tested a version with an increased broadcast range of over 3m.
Further developments could include sensor tags that would be embedded within the composite structure to monitor stresses, strains and fatigue.
Source: Flight International
