We found that of the 46 individual fixed- and rotary-wing types of aircraft we examined, only three met the service-established mission capable goal [80 percent] for fiscal year 2019. In addition, we found that 24 aircraft in our review did not meet their annual mission capable goals for any year from fiscal year 2011 through fiscal year 2019 and only three met their annual mission capable goals in a majority of those years, as shown in figure 1 below.
We also analyzed the O&S costs on a per aircraft basis to account for differences in the fleet size of various aircraft types. We found that fiscal year 2018 per aircraft O&S costs also varied across platforms, as shown in figure 5.
That was from the GAO report, Weapon System Sustainment: Aircraft Mission Capable Rates Generally Did Not Meet Goals and Cost of Sustaining Selected Weapon Systems Varied Widely.
Poor Data Presentation
Both of those analyses above were rendered largely useless. First, I wanted to see aircraft availability rates (where possible) and not just mission capable rates. I’m sure the reason the DoD wants to keep these hidden from the public is embarrassment. But other than that, just show a table or line chart with the individual rates over time.
Second, the chart shows O&S cost per aircraft over a year. Thanks, I guess. Now I have to go track down the average number of flight hours per aircraft in 2018 to get to the metric that I want to see: cost per flying hour. I’d expect F-35s to appear cheaper because they probably fly less than an F-16, for example (see end note).
What’s up with maintenance?
Another difference between them is that for the F-16, about 30% of O&S cost is maintenance, compared to nearly 50% for the F-35A. By contrast, the F-35B and C models have even an *lower* maintenance intensity than the F-16, roughly 20% of total O&S costs. How is that possible? It should seem obvious that the more complicated and less mature F-35B/C models would require a greater degree of maintenance.
Indeed, since 2013, F-35A maintenance cost per aircraft as grown slightly while decreasing for the B and C models. This seems to be offset the F-35A having very little in terms of sustaining support or continuing system improvements, while for the B and C models those costs eat up more than 50% of total O&S.
In terms of annual unit costs (per aircraft, not flying hour), the Air Force F-35A maintenance costs were well above $4 million per aircraft in 2018 compared to Navy models closer to $2 million.
I’m not saying that through Contractor Logistics Support contracts, Navy F-35 costs are spread onto the Air Force… but that’s kind of how it looks, right? Perhaps some of this is an artifact of how the Air Force and Navy collect and report O&S costs differently.
Explaining the cost differentials
I’d guess that the Air Force recognizes this maintenance cost differential. Why would they let it persist? One theory is that the Air Force is a terrible contract negotiator, or the Navy is uniquely excellent. Perhaps sortie rate differences have some effect, the Air Force puts more wear and tear. Another theory is that my intuition is plain wrong, F-35As are more maintenance heavy than Bs and Cs. Certainly the accounting differences between the services plays some role.
A final theory I’ll throw out is that the Air Force recognized the need to keep the Navy in the program to keep their overall F-35 costs lower through economies of scale. In other words, the Air Force picks up some of the maintenance tab in order to allow the Navy to use its O&S funds for continuing systems improvements. That might have amounted to $1 billion or so over the last 4 years. (“Sustaining support” costs can include systems engineering, simulators, and IT systems.) Perhaps, without those “free” improvements, the Navy would have already dropped out like it did during the joint F-111 program.
What other explanations are there? Enter your thoughts in the comments! Here’s another interesting bit:
DOD originally planned to have [F-35] repair capabilities at the depots ready by 2016, but the depots will not have the capability to repair all parts at expected demand rates until 2024. As a result, the average time taken to repair an F-35 part was more than 6 months, or about 188 days, for repairs completed between September and November 2018—more than twice as long as planned.
End Note: Annual flying hours
The F-35A supposedly cost $44K per flight hour in FY 2018. The GAO reported 134 F-35A aircraft at a total sustainment cost of $1.2 billion, or $8.95 million per aircraft. Dividing that by $44 thousand, we arrive at roughly 203 flying hours per aircraft.
For the 940 F-16s in the inventory at a total O&S cost of $4 billion, and let’s call it $15K per flying hour, we get 283 hours per aircraft.
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