Scheduled Maintenance Tasks

Scheduled Maintenance Tasks

Working through the development process with the Maintenance Steering Group

By Jack Hessburg

March 2000

How are maintenance tasks developed? The airworthiness regulations identify a requirement titled Instructions for Continuing Airworthiness. For example, FAR 25.1529 and FAR 25, Appendix H cover transport category airplanes. The contents of these FARs impose, among other things, the following obligations upon the applicant for a Type Certificate:

"Scheduling information for each part of the airplane and its engines, auxiliary power units, propellers, accessories, instruments, and equipment that provides the recommended periods at which they should be cleaned, inspected, adjusted, tested, and lubricated, and the degree of inspection, the applicable wear tolerances, and work recommended at these periods. Also, "The recommended overhaul periods and necessary references to the Airworthiness Limitations, which set forth each mandatory replacement time, structural inspection intervals, and related structural inspection procedures. In addition, they must include an inspection program that includes the frequency and extent of the inspections necessary to provide for the continued airworthiness of the airplane." And, "ÉAccumulated flight hours, calendar time, number of operating cycles or the number of landings are the generally accepted measurements used when specifying maintenance intervals."

Maintenance Steering Group dynamics
A group known as the Maintenance Steering Group (MSG) develops the maintenance requirements identified by these FARs. This group is composed of representatives of airplane, component and engine manufacturers; air carriers, both foreign and domestic; and FAA and foreign regulatory agency observers.

The MSG is divided into three bodies; the steering committee, working groups, and FAA and foreign regulatory observers.

The steering committee supports and directs working groups. It defines the number, type, and composition of working groups; documents group proposals into a unified maintenance inspection plan; and coordinates MSG activities with the certifying FAA region.

The working groups identify and analyze maintenance significant items, beginning with the original list prepared by the manufacturer. The number of groups is determined by the steering committee. Usually there are separate groups for each system, i.e. hydraulics, flight controls, structures, etc. Membership in each group is composed of specialists from the interested disciplines. The exact size and composition of the working groups is quite flexible and depends upon the needs of the moment as the analysis proceeds. Sub-groups may be formed to resolve complex issues. The manufacturer's personnel play a large role, counseling the groups regarding details of the design.

FAA observers, usually members of the FAA Maintenance Review Board (MRB), offer guidance and participate in the work of the steering committee and working groups. This has several advantages such as the (hopeful) resolution of regulatory issues regarding the recommendations and time saved discussing details of the analysis to name a few, when the MSG formally submits its recommendation to the FAA. Today, observers from various foreign regulatory agencies such as the JAA also participate in the process. MSG methods

The methods used by the MSG are described in a document issued by the Air Transport Association (ATA) titled Maintenance Program Development Document MSG-3 and include defining Maintenance Significant Items (MSI)