During the 1970s and 1980s the Bureau of Inspection and Survey (INSURV)
identified Electromagnetic Environmental Effects (E3) as a pandemic
problem representing the number one difficulty with electronic systems operating
within the fleet. Reliability, accuracy and mission degrading factors were
traced to the inability of electronic systems and devices to operate
satisfactorily in their intended electromagnetic environment. Each of the Naval
Systems Commands established programs or expanded the capabilities and
responsibilities within existing organizational elements to programmatically
address, control and prevent these problems, vice simply react to worst case
The Naval Air Systems Command established the Electromagnetic Environmental
Effects Branch. Its purpose was to assure sustained combat readiness of naval
aviation assets in the operational electromagnetic environment. E3
awareness training was subsequently developed foray fleet personnel, from the
squadron maintainers to Naval Aviation Depot engineers. Course objectives were
to identify and correct E3 problems and to take action to prevent
reoccurrences. This training was developed specifically for each skill level
including design, manufacturing, operation and maintenance, and is mandatory if
E3 problems are to be eliminated.
While the engineering solutions to most E3 problems have been
known for many years, they continue to persist. Among the reasons is that the
electromagnetic environment continues to evolve in both spectrum usage and power
levels employed. For example, as a weapon system's functions are modernized,
electronic devices for flight control, navigation and target acquisition become
more sophisticated. This in turn results in greater system sensitivity and a
higher density of environmental signals, setting the stage for even greater EMI
susceptibility and vulnerability.
The solution to this problem deals with managing the spectrum adequately, as
well as improving the hardening of electronic devices to their environment.
Additional E3 disciplines are therefore required during design,
manufacturing, operation and maintenance of these modern weapons systems. This
solution, however, introduces another factor the cost of acquisition. And with
the current U.S. Government initiative to release areas of the electromagnetic
spectrum previously reserved for military operations to civilian activities, the
imposition of greater EMC engineering criteria for acquisition of military
systems becomes even more crucial.
In this age of budget reductions and close cost management, production
engineers must seek innovative ways to improve producibility and reduce
manufacturing costs, thus delivering the product at greatly reduced expense.
This process encourages the use of non-developmental equipment. Effectively
integrating this equipment, which may not have been E3 hardened, into
a cost-effective operational war fighting system requires a combination of
E3 hardening techniques and producibility methods.
While E3 control involves complex interactions among several
engineering disciplines, most are applications of practical engineering
techniques. Once the electromagnetic design has been completed, the application
falls to the practical uses of materials and processes, such as corrosion
control and structural assembly, as well as the broader control of system
Compiling a single document to address all aircraft E3 control
practices would require several volumes, and would be impractical to use.
Although E3 manuals and books have been published and are available
from commercial publishers, those documents are often too general. Therefore,
rather than issuing a single E3 Best Manufacturing Practices (BMP)
document, the task of recording and distributing EMC best practices has been
divided into development of a series of smaller documents that are timely in
preparation, review and publication, and can facilitate updates.
The process of developing the first EMC guideline document has been a joint
effort between industry and U.S. Navy technical experts. It has been developed
using the best capability of both industry and Navy, and has been submitted to
major industry technical associations responsible for reviewing proposed
military E3 documentation. At each step in the process, cooperative
reviews were conducted utilizing the resources of industry technical committees,
appropriate NAVAIR and other Systems Command E3 experts, and
additional interested industry representatives.
Because different manufacturers may have different (though equally valid)
processes for accomplishing the same E3 tasks, it is important that
these BMP documents contain consistent basic requirements and yet allow for
variations in implementation details.
While a single document may originate from a small group of industry sources,
the entire industry has been queried to provide input for consideration during
the formal review process. The comments and recommendations of those who
responded to support development of this first document are included. It is
anticipated that publication of this and subsequent E3/EMC Best
Manufacturing Practices series documents will foster an even wider participation
and input. Though preparation of best practices documents under the BMP program
are normally based on industry input, it is planned that modifications to this
and future EMC best practices publications include a more comprehensive input
from additional DoD activities as well.