Contracting Agency: U.S. Air Force
Point of Contact: solutions@kbsi.com

Overview

Current aircraft engine maintenance activities performed by the Air Force must account for both scheduled and unscheduled maintenance needs. These maintenance activities, whether scheduled or unscheduled, are characterized as following an on-condition maintenance (OCM) strategy: the maintenance work is performed to repair only what is broken or has already exceeded its time on wing (TOW) limits.

This OCM strategy, however, suffers from two shortcomings: the strategy does not opportunistically account for maintenance tasks that can be expected to occur before a defined TOW target and neither does it attempt to reduce the consequences of potential part failures as opposed to simply the number of failures. Equally important, OCM does not involve the advanced planning needed to optimize unit aircraft availability over time. This is in keeping with the goal of current engine maintenance approaches which is not to necessarily maximize overall unit aircraft availability, but instead to maximize earned labor hours against those available (measured as 'efficiency'). The assumption is that maximizing efficiency (i.e., utilization) will directly translate into increased aircraft availability. Instead, maximizing efficiency may (and often will) lead to sub-optimized availability and higher maintenance costs.

OCM also involves frequent inspections, part replacements, and rework in an attempt to maintain high standards of system reliability. Frequent maintenance requires that a large inventory of spare engines and engine components be maintained. However, how much of this cost is truly needed to ensure the same level of reliability and availability is not known.