Maintenance Program Enhancements
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Boeing continues to seek optimization of its maintenance requirements using improved data collection and the ISC processes. Boeing is currently developing a program that collects and stores real-time in-service data from scheduled maintenance visits in a line and hangar environment and associates this data with the scheduled maintenance task. The program enables data to be gathered and analyzed centrally for use by the industry in adjusting current scheduled maintenance tasks or check intervals based on in-service findings.

This will allow ISCs to be more proactive in managing scheduled maintenance programs. It also will allow operators to benchmark against other participating operators, expedite ground times for line and hangar maintenance visits, and plan spares and consumables using worldwide averages for scheduled maintenance.


The ISC process maintains safety and reliability standards and reduces waste by ensuring maintenance tasks are performed at the proper level of intensity and interval, based on industry in-service flight data and each airplane modelís inherent design characteristics.

Data collection and operator participation in the ISC process remain key factors in future scheduled maintenance program improvements. For more information, contact Brian McLoughlin at MaintenanceEngineering@boeing.com.

history of

In the early days of aviation, maintenance programs were developed by mechanics. The programs were simple and without analytical basis. The formation of airlines created the need for new regulations and broader regulatory involvement in maintenance requirements.

With the entry of large jet airplanes into the commercial market in the 1950s, the airplane manufacturer became the source of maintenance program development. The underlying concept was to overhaul every component at a given time. In 1960, the industry formed a task force to investigate the capabilities of preventive maintenance. The findings of the task force led to a new type of maintenance called “on-condition” maintenance.

The handbook “Maintenance Evaluation and Program Development,” also referred to as “MSG-1,” was developed in 1968 for the 747 by the Air Transport Association (ATA) Maintenance Steering Group (MSG), a group of airframe manufacturers, airlines, U.S. Federal Aviation Administration (FAA) representatives, and suppliers. MSG-1 used decision logic to develop scheduled maintenance.

For aircraft in the 1970s, the document “Airline/Manufacturer Maintenance Program Planning,” or “MSG-2,” was developed. It was process oriented and analyzed failure modes from the part level up. The MSG-2 philosophy was based on the theory that all airplanes and their components reach a period when they should be “zero timed” or “overhauled” and restored to new condition.

In 1978, United Airlines, commissioned by the Department of Defense, developed a methodology for designing maintenance programs based on tested and proven airline practices. This new methodology was the basis for MSG-3, the current industry standard.

This methodology has a task-oriented approach to maintenance that analyzes system failure modes from a system level, or top down. Maintenance tasks are performed for safety, operational, or economic reasons. They involve both preventive maintenance and failure finding tasks.

Revisions to the MSG-3 philosophy have provided added methodology for improving coverage of all modes of failure, such as inclusion of the Corrosion Prevention and Control Program, Enhanced Zonal Analysis, and Lightning/High Intensity Radiated Fields.

Boeing continues to work with airplane operators, regulators, and the ATA to update MSG-3 to enhance the methodology.

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