To successfully adapt to this changing environment, both designers and users of aerospace systems must understand the following and address them in new ways:

1. Scope of the component obsolescence problem.
2. Selection and management of electronic components.
3. Design of electronic systems and equipment.
4. Operation, maintenance, and support of electronic equipment.
5. Qualification and certification of electronic equipment.

1. SCOPE OF THE COMPONENT OBSOLESCENCE PROBLEM
Electronic component obsolescence is a major problem for military and commercial aerospace manufacturers. It is estimated that 60 percent of the integrated circuits currently on aerospace products will be obsolete (out of production) within five years because production cycles of today’s components are far too short to support aerospace products whose useful lives exceed 30 years.

In the past, military components were in production for several decades, but most current commercial and industrial designs are in production for five years or less and the life span of those designs continues to shrink. A state-of-the-art graphics processor used in a military display is currently being redesigned with new technology every 11 months. Figure 3 illustrates how several generations of components will be required to support military and commercial airplanes throughout their production and service lifetimes. If not properly addressed, this will result in frequent design changes and equipment recertification efforts and cause shortages of replacement components to support repairs of existing equipment.

Boeing, McDonnell Douglas, and Rockwell were working independently on the component obsolescence problem before their merger. Now operating under one name, they are working together, and with suppliers and customers, for an integrated solution to the problem of component obsolescence.

In addition, Boeing has established a companywide obsolescence management board to address issues related to component obsolescence. The board is identifying processes, tools, and communications structures for common obsolescence management solutions across Boeing before finalizing its specific objectives.

2. SELECTION AND MANAGEMENT OF ELECTRONIC COMPONENTS
In 1991, Boeing Commercial Airplanes Group initiated a program that requires suppliers of electronic equipment -- original equipment manufacturers (OEM) both internal and external to Boeing -- to document the processes used to select and manage components. Approved components must comply with an approved plan, making OEMs responsible for managing the components used in their equipment. Commercial Airplanes and its customers are no longer involved in day-to-day piece part selection, allowing the transition to readily available commercial and industrial components and replacing the limited-availability military components. As a result, OEMs have greater flexibility in equipment design, component selection, and their response to component obsolescence problems, which reduces costs.

In 1998, Boeing Military Aircraft and Missile Systems developed a single component management plan to cover many of its aircraft, including the Apache, AV-8B, F/A-18, F-15, and T-45. This plan permits OEMs to develop their own component management plans to address the aircraft performance requirements. After Boeing approves an OEM’s plan, the OEM selects and uses components with limited intervention or oversight from Boeing or the U.S. Department of Defense.

The approaches of the two Boeing operating groups are quite similar, but not identical. Because many OEMs supply equipment to both groups, they would like to use common processes for both commercial and military equipment. Other airframe manufacturers have also expressed interest in implementing similar programs. In response, Boeing is leading an effort to develop international standards that will allow aerospace OEMs to use the same component management processes for all programs and customers. This effort is the responsibility of an avionics working group, authorized by the International Electrotechnical Commission (IEC). The working group includes most of the airframe and electronic equipment manufacturers in North America and Europe, as well as defense agencies and the U.S. Federal Aviation Administration (FAA).

To minimize costs and ensure uniformity, the working group is developing international standards to make sure that all components used in aerospace equipment are selected, applied, and placed in service according to documented, consistent, and controlled processes. The working group is also developing standards for using electronic components outside the temperature ranges specified by the component manufacturers. The standards will lead to a controlled process for ensuring that the requirements are met when it is necessary to use a component that was initially targeted for the computer or telecommunications industry.

After these industry standards are released, OEMs will use them to document their processes in companywide electronic component management plans for selecting and managing electronic components. Following approval of the OEM plans by individual customers (e.g., airframe manufacturers and military agencies) or by the IEC, all components selected and managed according to those plans will be considered approved for their applications. This will reduce costs, improve efficiency, and allow flexibility for the OEMs, whose customers will not be required to be involved in the details of decisions about their components.

Several OEM suppliers to Commercial Airplanes already have approved plans based on the Boeing electronic component management program. With minor modifications, most of those plans should conform to the provisions in the IEC standards.

3. DESIGN OF ELECTRONIC SYSTEMS AND EQUIPMENT
Component obsolescence is forcing OEMs to change how they design equipment. Boeing is managing this situation through the following activities:

• Review performance requirements.
• Conduct design review assessments.
• Anticipate component technology trends.
• Develop avionics technology roadmaps.
• Plan for system upgrades.
• Ensure flexibility of design and redesign.

Review performance requirements.
Boeing is reviewing environmental requirements to ensure that they do not include unnecessarily high or low operating temperature requirements. Temperature requirements for the aerospace industry were developed when components were widely available for operation in the temperature range from -55°C to 125°C (-67°F to 257°F). It was convenient to specify equipment environments for this range because the cost of components was small compared with the cost of defining every environment exactly. Today, however, design margins are not as wide, and it is more cost effective to specify precise temperature requirements. In some recent instances, the temperature requirements for some equipment have been respecified, resulting in lower costs and improved supportability without compromising the equipment quality or reliability.

Eliminating "how-to" requirements for OEMs is also key to managing component obsolescence. Requirements that specify component package type or package material have no place in a performance specification unless safety is a factor. Boeing has streamlined performance specifications to reflect these changes.

Conduct design review assessments.
A component obsolescence assessment is now included in major design reviews for Boeing electronic equipment. These reviews include estimates of the expected availability of the electronic component, and address provisions to ensure that the equipment will be available and supportable throughout the equipment production and service life. Avionics technology roadmaps (see below) will be discussed in the design reviews to provide visibility of the technical and cost implications of component obsolescence in design decisions.

Anticipate component technology trends.
The timing of specific component changes cannot be predicted accurately, but designers of the original equipment must anticipate general trends. For example, a well-known principle of semiconductor products is Moore’s Law, which states that a semiconductor device will double in complexity every 18 months. New designs should provide design and layout flexibility to accommodate these trends. Research facilities available to Boeing are investigating component trends through discussions with component manufacturers, and the resulting information is being published as it becomes available.

Develop avionics technology roadmaps.
Boeing is working with the aerospace industry to develop avionics technology roadmaps to help predict electronics technology trends and anticipate other forces that will affect the way avionics equipment and systems are designed, produced, and supported. The roadmaps will include information about component trends and the effects of component obsolescence. Boeing will use the roadmap information to coordinate future designs and upgrades.

Plan for system upgrades.
When system upgrades are necessary, Boeing plans them, minimizes their effect on the customer, and optimizes the cost tradeoffs. Typically as components become obsolete, it is necessary to redesign the equipment or to make a last-time buy of the component to maintain production and provide long-term support. Both alternatives are expensive and require cost tradeoffs to determine the optimal solution. If the equipment is currently in production, it is often best to plan a redesign and then buy a sufficient quantity of components to support the equipment until the redesign is available. Boeing has developed a model to estimate the best time to redesign. The model considers costs of inventory, design, recertification, and potential obsolescence of other components in the equipment (fig. 4). The model uses net present value analysis and defines the most favorable redesign time as the point at which the total cost is lowest.

Ensure flexibility of design and redesign.
Several design concepts are being used to ease the effects of design changes caused by component obsolescence. These concepts include using open system architecture to define the parameters and interfaces of systems, equipment, and subassemblies; defining complex elements with a hardware description language; partitioning designs to place high-risk components on throwaway modules; reusing common designs and minimizing the number of high-risk components; adopting industry standard interfaces and data formatting; and providing for future changes in the initial circuit design.

4. OPERATION, MAINTENANCE, AND SUPPORT OF ELECTRONIC EQUIPMENT
Component obsolescence complicates the maintenance and support of aerospace equipment. For example, the number of component package styles has increased rapidly in recent years. Because many of them require specialized assembly equipment, materials, and processes, it may not be realistic for all maintenance shops to develop the capability to replace components on circuitboards. In the future, repair facilities with specialized processes and equipment may have to perform this activity to minimize cost.

Other industries accommodate obsolescence by placing potentially obsolete components on throwaway printed circuit cards, for example, the microprocessor card in a personal computer. This practice has not been used widely in aerospace, but it is being evaluated.

Because currently available components have more limited temperature ranges than older components, Boeing is reviewing system temperature requirements and airline maintenance procedures. System temperature requirements for electronic equipment are derived from standard industry specifications and do not take into consideration airplane maintenance practices in extremely hot and cold environments. If procedures have been documented for maintenance and operation in extreme conditions, and the effect on the operator is minimal, Boeing may allow OEMs to use components designed for use in a more limited temperature range. For example, Boeing has documented procedures for preparing the airplane for operation when the outside temperature is below -40°C (-40°F). These procedures require lavatory, battery, and certain hydraulics systems to be warmed before use because the viscosity of the fluids in the systems inhibits functionality at low temperatures. As a result of documenting the necessary procedures for these systems, requirements for some nearby electronic equipment could also be revised.

Boeing is also surveying operators to determine if procedures should be developed for hot-weather maintenance and operations. These procedures would document the normal practices that airlines use to cool airplanes in extremely hot temperatures. Boeing may adjust high-temperature requirements if the effect on operators is negligible. Similar techniques may be employed on military airplanes if using them does not create intolerable operating limitations.

Support practices and contracting methods for military avionics are being reviewed and compared with commercial avionics support agreements and relationships. In response to a number of industry trends, including component obsolescence, the current trend is to add or restructure maintenance agreements and practices to emphasize or guarantee long-term availability of systems and equipment.

5. QUALIFICATION AND CERTIFICATION OF ELECTRONIC EQUIPMENT
Regulatory agencies do not approve specific electronic components in the commercial avionics industry. Approval occurs with demonstrated performance at the equipment level; when a new equipment design is certified, the parts used in the design are included in the certification. The military procurement policy for part usage in new systems has made considerable progress in this area during the past few years. When component obsolescence or equipment modification makes it necessary to replace a part in equipment that has already been certified, the process for approving the replacement part is based on proving, by test or analysis, that the equipment function is maintained.

FAA regulations require replacement and modification parts to be obtained from manufacturers with Parts Manufacturer Approval. If such a part is not available, a few exceptions, including the use of a standard part, are allowed. In response, the aerospace industry has proposed the following definition of an electrical or electronic standard part:

"A part that is produced in conformance with a specification published and maintained by a consensus standards organization, a government agency, or a holder of a design approval, and used within the manufacturer’s operating characteristics and environmental ranges; or selected, applied, and managed by the design approval holder in conformance to an industry consensus component management document."

The last clause of the definition can be satisfied by the industry consensus component management documents being prepared by the IEC working group.

LLOYD CONDRA
ASSOCIATE TECHNICAL FELLOW
MATERIEL SYSTEMS AND EQUIPMENT SUPPORT
BOEING COMMERCIAL AIRPLANES GROUP

DAVID FOLLOWELL
ASSOCIATE TECHNICAL FELLOW
SUPPORT SYSTEMS
BOEING MILITARY AIRCRAFT AND MISSILE SYSTEMS

GARY HOUCHENS
ASSOCIATE TECHNICAL FELLOW
CENTRAL PARTS ENGINEERING
BOEING PHANTOM WORKS

JERRY JENKS
DEPARTMENT HEAD
SUPPLIER MANAGEMENT
BOEING MILITARY AIRCRAFT AND MISSILE SYSTEMS

MATT KOEHLER
SENIOR SPECIALIST ENGINEER
MATERIEL SYSTEMS AND EQUIPMENT SUPPORT
BOEING COMMERCIAL AIRPLANES GROUP

ZELL PORTER
MANAGER, CUSTOMER SUPPORT/ ELECTRONICS TEST
COMMERCIAL AVIONICS SYSTEMS
BOEING COMMERCIAL AIRPLANES GROUP