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DoD Releases New Report on the Effect of Corrosion on the Cost and Availability of Army Aviation and Missile Systems

LMI was asked by the Department of Defense (DoD) Corrosion Prevention and Control Integrated Product Team (CPC IPT) in August 2012 to measure the effect of corrosion on the availability and cost of Army aviation and missile systems. Using data from fiscal year (FY) 20121, LMI estimated the annual corrosion-related cost to be $1,963 million, or 21.9 percent of the total maintenance costs for all Army aviation and missile systems. We also estimated that corrosion was a contributing factor in 2,026,102 non-availability hours for Army aviation assets. This figure represents 18.1 percent of the total non-availability hours reported by the Army for its aircraft and equates to an average of 472 hours, or 19.7 days, of corrosion-related non-availability per year for Army aircraft or missile systems.

This review, which is funded by DoD, is part of a multiple-year plan to measure the effect of corrosion on DoD weapon systems. It is the third study to assess the effect of corrosion on maintenance costs and the second study to analyze the effect of corrosion on Army aviation and missile system availability. Table 1 lists previous Army aviation and missile system studies on the cost of corrosion, while Table 2 lists all DoD studies on the effect of corrosion on availability.

Maintenance expenditures fluctuate and supplemental maintenance funding is variable; so, too, are corrosion-related cost totals. Therefore, corrosion cost as a percentage of maintenance is a better indicator of any overall trends when looking at the effect of corrosion on the cost of weapon systems. The corrosion-related average of 21.9 percent of total annual Army aviation and missile system maintenance costs is roughly midrange for the DoD weapon systems LMI has studied. This percentage has been increasing steadily over the last four (4) fiscal years (FY2009–12).

The scope of LMI's study included all Army aviation and missile end items and major sub-components in inventory during FY2009–12. In that period, 69 types of aircraft and 12 missile systems existed at the type, model, and series level of detail, which equates to more than 4,500 aircraft and missiles2. Also included were 50,000 major aircraft and missile subcomponents.

To assess corrosion's effect, we segregated the Army's corrosion-related costs into three separate schemas: depot versus field-level maintenance, corrective versus preventive costs, and costs associated with structure versus parts. Table 3 shows both the costs and percentages within each schema for FY2012.

FLM accounted for 58.0 percent ($1,139 million) of the combined corrosion-related cost for Army aviation and missile systems within schema 1 ($1,963 million). However, in terms of percentage of overall maintenance, corrosion-related DM costs exceeded corrosion-related FLM costs. The corrosion-related DM cost as a percentage of total Army aviation and missile system DM was 29.3 percent; the same FLM measure was only 18.7 percent (see Table 4).

The remaining $53 million for corrosion-related maintenance that is outside normal reporting reflects the maintenance performed by operators with a non-maintenance occupation specialty, which typically is not recorded in standard maintenance systems.

Costs incurred to prevent corrosion (e.g., inspecting, treating, coating, washing) were far higher ($1,634 million versus $272 million) than those for corrosion-related corrective actions (e.g., fixing, replacing, and blasting). This 6-to-1 ratio is likely exaggerated by the lack of detail in Army maintenance records. The lack of descriptive text shifts the ratio of corrosion costs in favor of preventive classifications. Parts-related costs ($1,330 million) were also significantly higher than structure-related costs ($538 million).

LMI also stratified the corrosion-related costs of Army aviation and missile systems by type, model, and series; total cost; and cost per item, ranking systems by their total and average corrosion-related costs. Aircraft and missile systems with both a high total cost of corrosion and a high average cost of corrosion per item merit the most attention. LMI identified five aircraft that were among the top 10 contributors for both (see shaded entries in Table 5). Each of these five aircraft presents a specific opportunity for the Army to focus resources to mitigate the negative effect of corrosion.

Corrosion-related non-availability hours (2,026,102 hours) accounted for 18.1 percent of the total non-availability reported3. LMI shows in Table 6 the highest 10 contributors to corrosion-related non-availability hours. Two utility helicopters, the UH-60L and UH-60A, had the highest corrosion-related non-availability hours. The OH-58D observation helicopter accounts for both the highest percentage of corrosion-related non-availability hours to total non-availability hours, and the highest average corrosion-related non-availability hours per aircraft.

With the exception of the OH-58D, the range of percentages for corrosion-related non-availability hours in Table 6 is fairly narrow. This indicates common causes of corrosion likely affect these aircraft in a common way.

The relationship between corrosion cost and corrosion-related non-availability is strong for Army aviation and missile systems. The systems that experience the highest corrosion-related cost also suffer high corrosion-related non-availability (see Table 7).

Four of the 10 aircraft and missile systems with the highest total corrosion cost had no reported non-availability (depicted in the last four rows of Table 7). However, the six aircraft with the highest total corrosion cost were among the top eight aircraft for high, total, corrosion-related non-availability hours4.

This is actually good news. Efforts to mitigate the cost of corrosion on these aircraft should also increase availability.


1Data was collected for FY2009–12, but LMI based the corrosion-related cost and availability of Army aviation and missile systems on FY2012 data.

2To our knowledge, this includes all types of Army aviation and missile systems.

3LMI measured the total corrosion-related non-available hours in a manner consistent with how the Army reports its results that are not mission capable.

4This correlation was statistically strong. To calculate the correlation, LMI used a statistical formula based on an R-squared value. An R-squared value of 100 percent shows a perfect correlation; whereas 0 percent indi-cates no correlation at all. For the FY2012 study period, the R-squared value of the relationship between the corrosion-related cost and corrosion-related non-availability hour rankings by type, model, and series was 89 percent.



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