Strategies for Maintaining the Navy's and Marine Corps' Inventories of Fighter Aircraft

May 28, 2010

The United States Navy and Marine Corps operate a fleet of more than 1,100 tactical fighter aircraft that provide air-to-air and air-to-ground combat capabilities. Those aircraft include Hornets (F/A-18A, B, C, and D), Super Hornets (F/A-18E and F), and Harriers (AV-8B); within the next few years, a new and more advanced aircraft—the F-35 Joint Strike Fighter (JSF)—will start being added to the fleet. Although current plans call for the purchase of about 700 new fighter aircraft over the next 15 years, the Department of the Navy is projecting that purchases planned for the next 5 to 10 years will be unable to keep pace with the retirement of today’s Hornets as they reach the limit of their service life. In a report released today, CBO compares four alternatives for maintaining the Navy’s and Marine Corps’ fighter inventories.

The alternatives discussed in the report consist of different combinations of three approaches.  One approach involves extending the service life of Hornets by up to 600 flight hours (roughly two additional years) beyond the current 8,000-hour limit by modifying and inspecting those aircraft in the high-flight-hour (HFH) program (comprising a series of structural repairs and more-frequent inspections). A second approach would implement a service-life extension program (SLEP) of more-extensive modifications, which would enable Hornets to reach 10,000 flight hours, and the third would purchase more Super Hornets than current plans call for. Some HFH modifications have already been done, and Super Hornets are still in production—but research and planning for the Hornet SLEP is not expected to be complete until 2014 (the Navy has indicated that it may begin SLEP modifications on some aircraft as early as 2012).

Of the four alternatives that CBO analyzed, the first two are limited to extending the service life of existing Hornets. They are generally consistent with various plans the Navy has proposed or is considering:

  • Alternative 1: Execute the HFH program on the 509 Hornets suitable for those modifications;
  • Alternative 2: Execute the HFH program on 220 Hornets and the more-extensive SLEP on 289 Hornets.

The third and fourth alternatives would combine some service-life extensions for Hornets with changes in planned purchases of new aircraft:

  • Alternative 3: Implement the HFH program in the same way that Alternative 1 would, but also increase purchases of Super Hornets by 126 aircraft (beyond the planned total of 515) and decrease purchases of Joint Strike Fighters by 93 aircraft between 2018 and 2023;
  • Alternative 4: Modify 509 aircraft through the HFH process and purchase 126 additional Super Hornets, as in Alternative 3, but do not reduce purchases of JSF aircraft.

CBO measured the increase in inventory offered by those alternatives and the funding that each would require relative to a base case under which the service life of Hornets would not be extended and additional aircraft would not be purchased. CBO found that Alternative 1 would increase the Navy’s and Marine Corps’ fighter inventory by an average of 66 aircraft over the 2011–2025 period; Alternative 2 would add an average of 106 aircraft to the inventory; Alternative 3—an average of 128; and alternative 4—an average of 148.

Relative to the cost of the base case in which none of the three approaches are undertaken, the cost of Alternative 1 would be about $2.2 billion higher (in fiscal year 2010 dollars). Alternative 1 has the lowest total cost of the alternatives examined by CBO, but it provides the smallest increase in inventory.

Alternative 2 would provide the largest increase in inventory that can be achieved with the HFH and SLEP modifications currently being considered—but at a cost of about $7.7 billion, it would be more than twice as costly as Alternative 1 when measured per increment of additional service.

Alternative 3 would provide larger increases in inventory than would Alternatives 1 and 2. Moreover, each additional Super Hornet provided under Alternative 3 would offer improved performance (a more-capable radar, longer range, and the ability to carry more weapons) than would a SLEP Hornet. The reduction in JSF purchases would result in fewer of the most advanced aircraft after 2020. At about $3.8 billion to $4.8 billion higher than the cost of the base case, the total cost of Alternative 3 would fall between the costs of Alternatives 1 and 2. In the near term, however, the cost would be substantially higher than for Alternatives 1 or 2 because the savings from reducing JSF purchases would not offset the cost of new Super Hornet purchases until after 2017.

Alternative 4 would provide the largest increase in inventory before 2025 and would also provide increased inventory well beyond 2025, because additional purchases of Super Hornets would not be offset by fewer purchases of JSFs. The advantages of new aircraft provided in Alternative 4 would come at a cost of $12 billion to $13 billion more than under the base case (nearly all of which would be incurred in the next five years). Alternative 4 would be the most expensive per increment of additional service provided between 2011 and 2025.

CBO did not evaluate whether the inventories that would be realized under the various alternatives would be sufficient to meet the Navy’s and Marine Corps’ operational needs. Further, if additional delays were experienced with the JSF program, the inventories realized under all four alternatives would be lower, and any corresponding shortfall would be larger.

This report was prepared by David Arthur of CBO’s National Security Division.