by Dale Lillard, President & Lee Matthews, Operations Manager, Lansdale Semiconductor.
Remember the space shuttle Columbia? The same kind of strait-jacketed thinking that contributed to its failure is still hard at work in our government and may well contribute to failure of many of our nation’s military aircraft.
In 1987, the Government, faced with increasing obsolescence of military components, looked for a new way to combat the problem. Not believing that aftermarket manufacturing of product was a viable option, they commissioned a study on using BiCmos devices to emulate the functions of older bipolar devices, and the Generalized Emulation of Microcircuits (GEM) program was born. The current system of the Military Standards states that close enough is not good enough. High reliability military platforms are designed and built from high reliability subsystems, which are designed and built with high reliability components. When one of those components becomes obsolete and is replaced by a different part, intensive engineering studies and testing are performed at the component, subsystem, and even system levels to ensure the change will not affect system performance or reliability. Change Control and Configuration Management are the cornerstones for maintaining reliability.
Space Shuttle Disaster
The lack of Change Control and Configuration Management was a contributing factor in the crash of the Space Shuttle Columbia. Due to environmental concerns, the foam insulation’s configuration was changed. The design engineers who had initially developed the foam had retired, and the existing staff did not fully understand the requirements or their effect on the total system. Then the change was implemented without fully evaluating the change or or monitoring its effect on the total system. The net impact was an increasing amount of front surface wing damage from brittle foam particles, eventually leading the the catastrophic system failure. The same is true with the older systems that the GEM parts are being used in. The original design engineers are no longer available.
Configuration changes are being made by substituting GEM parts for the original parts without considering system behavioral compatibility, so catastrophic failures are only a matter of time. Since its inception, the Semiconductor Industry Association has had a problem with the GEM program. They see unfair competition in an already stressed market and GEM products being marked and sold under the same part numbers as the original parts even though they are produced using a different technology, a process which does not conform to best commercial practices, or Change Control and Configuration Management requirements.
Different routes have been taken to try and change this practice. Meetings have been held with Gregory Saunders of the Defense Standardization Program office, Rick Brophy (the previous GEM Program Manager), David Robinson (the current GEM Program Manager), Admiral Alan Thompson, Commander DSCC (defense Supply Center at Columbus), and even Senator John McCain. Presentations have been made at Conferences including COTSCON, DODDMS Teaming Group, Parts Standardization Management Committee, DMSMS, NAMSA, COG, CMSE, and the Joint FAA/DoD/NASA Conference on Aging Aircraft. Articles have been published in newspapers, Military and Aerospace Magazine and U.S. Tech.
Nothing has Changed
Characterization testing of 5 GEM devices compared to original devices showing the electrical differences has been performed, and that data is available at www.lansdale.com/gemhtml/wkparts.htm along with some of the correspondence to and from DSCC.
In 2003, the Government Electronics & Information Tech-nology Association and the JEDEC Solid State Technology Association addressed the issue again with a joint letter to Gregory Saunders. An excerpt from that letter reads: “Although we see the benefit of the GEM program for supporting obsolete integrated circuits for weapon system logistics, we are very concerned about the re-use of existing standardized part numbers to identify GEM emulated devices. One of the basic principles of Configuration Management states that if Form, Fit, or Function of an item changes, you must change the associated item number. In the case of GEM emulated devices, the form in the case of the device technology clearly changes…”
As a result the following motion was passed within the GEIA G-12 Committee 12-0-0:
“G-12 does not support an older technology product being emulated with a newer technology having the same part number because it is not identical in Form, Fit, and Function.”
The JEDEC JC-13.2 committee passed a similar motion to support the G-12 position, 10-0-1, with one abstention. Again the request for change fell on deaf ears.
In 2004, JEDEC JC-13.2 formed a task group to rewrite the definition of device type in MIL-PRF-38535 to add that device types must be within the same Microcircuit group. This was sent to ballot and passed 11-0-2 with 2 abstentions. JC-13.2 formally requested that the change be implemented in November 2005. In December 2005, DSCC responded: “DSCC has reviewed your comment and finds no technical basis for implementing the change.”
DSCC appears to believe there is no technical difference between a 7 micron Bipolar TTL device and a 1.5 micron BiCmos emulated device, even though the Semiconductor Manufacturers and the OEM system builders have jointly stated that there is. Evidently the rules are different for a government funded contract vs. a non-funded contract.
Now there is a new problem. Not only are GEM parts making their way undetectably into military systems but a contract for Advanced GEM is in the process of producing higher level products, again without changing the original, standardized part numbers.
The correction of the problem is simple. Products of different technologies must have different part numbers. Otherwise military systems are going to become unsafe at any speed.
News Article from May 2006 Issue of US Tech Interactive
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