Anticipated for the past several years, the application of radio frequency identification (RFID) tags for component tracking on commercial aircraft is upon us, at least for tags that are "passive," or without an integral power supply. Work on battery-powered "active" tags has begun.
This was the message delivered by industry experts in aerospace RFID who spoke during the recent Avionics Magazine webinar, “Airborne RFID: Radio Frequency Identification Takes Off.”
Current guidance on applying RFID tags on working aircraft is provided by an FAA advisory circular, AC 20-162, “Airworthiness Approval and Operational Allowance of RFID Systems,” dated Sept. 22, 2008. The advisory allows use of passive devices as long as they are not interrogated in flight or when an aircraft is on an active runway or taxiway. It succeeded a foundational FAA policy memo from May 2005 that declared passive RFID tags acceptable for use on civil aircraft under specified conditions.
The advisory circular “gives us the green light to start populating legacy airplanes that have already been delivered and new deliveries with passive RFID devices on the parts,” said Kenneth Porad, associate technical fellow and RFID program manager with Boeing Commercial Aviation Services.
“We will not have to recertify or requalify them, because the regulatory agencies have proclaimed that they do not impact form, fit or function of any installed system or equipment on the airplane,” Porad said.
‘We are good to go at this very moment to put passive devices on airplane parts. There’s no barriers to enter the market.’
— Kenneth Porad, Boeing Commercial Aviation Services
“That is the industry position that’s agreed upon by all the airframers in our supplier base. And so we are good to go at this very moment to put passive devices on airplane parts. There’s no barriers to enter that market.”
Boeing has about 65 people working full-time on RFID across the company, with some 50 pilot projects in place, Porad said. Those projects include supply chain management of incoming materials, tool tracking on the production floor and identifying consumables and perishables such as sealant used in manufacturing aircraft.
Airbus last January placed a multi-year order to equip its coming A350 XWB with RFID tags on some 1,500 parts to support aircraft configuration management, line maintenance, warehouse logistics, payload tracking and life-limited parts monitoring.
The airframers and their airline customers have cooperated on RFID development. “We agreed early on that this would be non-competitive and so we’ve been working with Airbus through the Air Transport Association and other standards bodies, including EPCglobal, so we could have non-conflicting requirements,” Porad said.
“To have inconsistent direction to common suppliers would be costly and foolish for both” Airbus and Boeing, he explained. “We have lots of customers that fly a mixed fleet. They fly some Boeing products and some Airbus products. And these airlines have told us, ‘Please, please do not deploy a solution that would require us to have two sets of infrastructure for a Boeing airplane or an Airbus airplane. And so we’ve met with Bombardier, Embraer, Airbus … and we are working together so there’s benefits across the whole supply chain.”
In the case of onboard, on-airplane parts marking, discussions involving Boeing and others have focused on line replaceable units, parts that are reparable as opposed to consumables, spare parts, dispatch-critical items, life-limited or time-controlled parts subject to airworthiness directives, and emergency equipment such as life jackets, first aid kits and breathing apparatus.
Getting to the stage of deploying RFID tags on “flyable” components has taken several years.
Reacting to what Porad described as an “explosion” of interest in RFID across varying industries at the start of the last decade, Boeing and FedEx in 2003 conducted an on-board evaluation of high frequency 13.56 MHz passive tags on an MD-10 freighter. While “that worked fine,” Porad said, the tags afforded a maximum, one-foot read range. The evaluation was replicated using 915 MHz UHF tags, “and lo and behold, we got 10 to 12-feet read range,” he said.
“That worked for us, because no matter where the mechanic was standing inside the fuselage, if he could go 12 feet either direction and up, he could capture information off all of the tags. We kind of proclaimed UHF passive, 860 to 960 MHz (as the frequency range) … and that was in line with EPCglobal’s thinking.” EPCglobal is a standards organization for Electronic Product Code and RFID technology.
Based on the results of the FedEx evaluation and a petition to FAA, Porad said, the agency released its policy memo of May 13, 2005, supporting on-board use of passive RFID tags.
Industry standards underpin RFID development for flyable components. Air Transport Association (ATA) Spec 2000 Chapter 9, “Automated Identification and Data Capture,” which is part of a set of e-business specifications developed by airlines and suppliers, provides industry guidelines for traceability, including the use of RFID to permanently identify parts and their lifecycle status.
AS5678, “Passive RFID Tags Intended for Aircraft Use,” was published in December 2006 by the Society of Automotive Engineers (SAE). It provides a requirements document for the manufacture of passive-only UHF RFID tags for aerospace, identifies minimum performance requirements for use on aircraft parts and specifies test requirements, including compliance with RTCA DO-160E environmental test criteria.
SAE was in the early stages of drafting a new standard, AS6023, “Active and Battery-Assisted RFID Tags Intended for Aircraft Use.”
“Active RFID tags (those with a battery) are being widely promoted for aircraft applications,” states the rationale by SAE’s G18 Technical Committee for RFID in Aerospace.
“Some of the applications include sensing temperature, vibration, stress, fatigue, cargo handling, etc. Because these tags have a battery and transmit RF, there is a possibility they could interfere with safety of flight.”
Said G18 Committee Co-chairman Barry Allen, “from a technical perspective, there’s two issues with active tags that are of concern. The first is the proximity to sensitive devices. [T]he tag is physically attached to a device, and because of that, a much lower power has the potential to interfere. I’m not saying it will; I’m saying it has the potential. That’s what the concern is.
“And the second item is … the failure mode. What’s the worst-case scenario? With the passive tag, basically nothing can happen. It’s unpowered. But because you put a tag on that battery, is there a failure mode that can cause that tag to broadcast continuously, or (at) higher power? In the battery itself, we have to worry about safety risks.”
In addition to passive devices, FAA AC 20-162 also addresses use of Low-power active and Battery assisted passive (BAP) RFID devices. Low-power active devices consist of a low-power RF transmitter, an integrated circuit controller, memory, antenna and power source, according to FAA. BAP, or semi-passive, devices have their own power source, but the battery powers only the microchip, and the device transmits only when interrogated.
‘Onerous’ Process
While use of active tags on aircraft is a possibility, the qualification process is “onerous,” advised Allen. “It’s a very expensive process and, to my knowledge, nobody in the industry has actually gone through this entire process yet and is actively deploying active tag technology in flight,” he said.
“This is where most of the go-forward work has to be,” Allen said. “And there’s a lot of anecdotal evidence available out in the market for people who have tested and tried this. We have some in-flight tests FedEx did an extended test, UPS has done it (and) the U.S. Air Force has been flying this technology for many years with the Savi (tag) and now the ISO 18000-7” standard. Savi Technology, a Lockheed Martin subsidiary based in Mountain View, Calif., is the primary provider of active RFID technology to the U.S. Department of Defense and allied defense forces.
Added consultant Anthony T. “Buzz” Cerino, who has participated with the G18 committee, “One of the things that was found out during efforts to come up with the passive standard was that several organizations did look at active tags, battery-assisted passive tags, and found that many of them were very close to achieving the DO-160 requirement and, in fact, some did. That was one of the reasons why the committee felt that it would be reasonable and achievable to move forward with a requirements definition.”
‘What we are adding with extended memory… is a significant (parts) history under the ruggedized conditions for which aerospace exists.’
— Timothy Butler
President and CEO, Tego Inc.
Memory chip developer Tego, Inc., of Waltham, Mass., is supplying the 8 Kbyte chip specified by Airbus for the A350XWB, in an order announced Jan. 19, 2010. It will be contained in tags designed by MAINtag SAS of Paris.
In November, Tego announced the availability of aviation-grade RFID tags developed by Marubeni Chemix Corp., of Tokyo, and containing “TegoChip” technology. The Marubeni TAGAT tags, available with 4 Kbyte of memory, are tested to SAE AS5678 for flyable parts, are compatible with ATA Spec 2000 and are interoperable with standard UHF Gen2 readers, the company said.
“What we are really adding, with extended memory capability, is a whole history now, so that throughout the value chain, you can have a significant history over a long period of time under the ruggedized conditions for which aerospace exists, to have visibility into a whole range of parts and information that hasn’t existed before,” said Timothy Butler, Tego president and CEO.
Butler said his company can provide a platform with up to 32 Kbytes of memory, a multiple of those chips now in volume production.
“The current chip today will hold up to 35 to 40 pages of information. Think of it less like a chip and a tag and more as a USB device,” he said. There is “the ability to actually now hold pictures, data, encryption — all sorts of information that you would never have thought (possible) before.”
Butler offered a scenario of how on-board RFID tracking will benefit aerospace. An avionics manufacturer “builds a part for a Boeing or an Airbus plane that gets deployed into an Air France plane that gets service,” he said. “But 10 years later, maybe in Costa Rica or Milan, the information about those assets and those parts that are being replaced today doesn’t go along with those assets, and people have no idea what’s actually happening with that information. They don’t even know for sure whether or not it’s a counterfeit part, for instance.
“The ability to have visibility into this, the ability to carry the information with those assets and pull the information off by each of those major players has huge value across the industry.” —Bill Carey