We testified before the Senate Committee on Armed Services in September 2017 after four significant mishaps at sea resulted in the loss of 17 sailors’ lives and serious damage to Navy ships. We reported on some of the Navy’s challenges, including the degraded condition and expired training certifications of ships homeported overseas, reductions to ship crews that contributed to sailor overwork and safety risks, and an inability to complete maintenance on time. Since that time, the Navy has completed two internal reviews to address these and other challenges, identifying 111 recommendations to improve surface fleet readiness. The Navy formed an executive group to guide and closely track the implementation of recommendations, and its reform efforts are ongoing. As of November 2018, the Navy reported that it had implemented 78 (i.e., 70 percent) of these recommendations. Navy officials recognize that full implementation will take significant time and management attention to address the fundamental readiness challenges identified. In figure 1, we show photographs of two of the four Navy ships involved in significant mishaps that occurred in 2017. Both the USS Fitzgerald and the USS John S. McCain were involved in collisions that resulted in sailor fatalities. DOD has reported that more than a decade of conflict, budget uncertainty, and reductions in force structure have degraded its readiness; in response, the department has made rebuilding readiness a priority. The 2018 National Defense Strategy emphasizes that restoring and retaining readiness across the entire spectrum of conflict is critical to success in the emerging security environment. Nevertheless, DOD reported that readiness of the total military force remains low and has remained so since 2013. Our work has shown that the Navy has experienced increasing maintenance challenges as a high pace of operations has continued and maintenance has been deferred. Maintenance and personnel challenges also hinder readiness recovery of Navy aircraft. For the Marine Corps, our work has shown that ground force readiness has improved and remained stable in recent years, but acute readiness problems remain in aviation units. Over the past year, DOD has made department-wide progress in developing a plan to rebuild the readiness of the military force, with the military services providing regular input on the status of their readiness recovery efforts. In August 2018, we reported that the Office of the Secretary of Defense has developed a Readiness Recovery Framework that the department is using to guide the services’ efforts and plans to use to regularly assess, validate, and monitor readiness recovery. The Office of the Secretary of Defense and the services have recently revised readiness goals and accompanying recovery strategies, metrics, and milestones to align with the 2018 National Defense Strategy and Defense Planning Guidance. We have ongoing work assessing DOD’s progress in achieveing its overall readiness goals. DOD’s readiness rebuilding efforts are occurring in a challenging context that requires the department to make difficult decisions regarding how best to address continuing operational demands while preparing for future challenges. Our work has shown that an important aspect of this, across all of the services, is determining an appropriate balance between maintaining and upgrading legacy weapon systems currently in operational use and procuring new ones to overcome rapidly advancing future threats. Based on updated information we received in November 2018, the Navy has taken steps to provide dedicated training time so its surface forces may meet existing Navy training standards and their training is certified when they deploy. However, the Navy continues to struggle with rebuilding the readiness of the existing fleet due to enduring maintenance and manning challenges. As the Navy seeks to expand its fleet by 25 percent, these challenges will likely be further exacerbated and the Navy will likely face additional affordability challenges. After the collisions in 2017, the Navy focused on training surface ship crews to its existing standards. We testified in September 2017 that there were no dedicated training periods built into the operational schedules of the cruisers and destroyers based in Japan and 37 percent of training certifications for these surface ship crews had lapsed as of June 2017. Since that time, the Navy has worked to ensure surface ships are certified before they are deployed. For example, the Navy has established controls to limit waivers that allowed training lapses to worsen, now requiring multiple high-level approvals for ships to operate uncertified. Based on our analysis of updated data, the Navy has improved markedly in the percentage of cruisers and destroyers with lapsed certifications in Japan, from 41 percent of certifications expired in September 2017 to 9 percent as of November 2018, with less than 3 percent of certifications expired on ships in operational status. While the Navy has demonstrated its commitment to ensuring that crews are certified prior to deploying, training for amphibious operations and higher-level collective training may not be fully implemented for several years. In September 2017, we reported that some Marine Corps units were limited in their ability to complete training to conduct an amphibious operation—a military operation that is launched from the sea to introduce a landing force ashore—by several factors, including a decline in the number of amphibious ships from 62 in 1990 to 32 as of November 2018, access to range space, and a high pace of deployments, among others. We recommended that the Navy and the Marine Corps develop an approach to mitigate their amphibious operations training shortfalls as the services await the arrival of additional amphibious ships into the fleet. Marine Corps officials told us that the Marine Corps and the Navy are working together to maximize amphibious training opportunities. Additionally, the Navy has plans to phase in high-level collective training into the operational schedules of its ships homeported in Japan over the next several years. Previously, advanced and integrated training involving multiple ships was conducted ad hoc if at all for ships homeported in Japan. Such collective training is important because the 2018 National Defense Strategy states that the department’s principal priority is to prepare for threats from strategic competitors due to the magnitude of the threat they pose. However, in November 2018, officials from Fleet Forces Command told us that fully implementing its training approach to prepare for advanced adversaries would not be fully implemented across the fleet for several years. We have reported that the Navy faces persistent challenges in completing maintenance on time and providing sufficient manning to its ships. Unless these challenges are addressed, the Navy will be hampered in its ability to rebuild readiness and prepare for the future. Our work has found that the Navy has been unable to complete ship and submarine maintenance on time, resulting in continuing schedule delays that reduce time for training and operations and create costly inefficiencies in a resource constrained environment. The Navy’s readiness recovery is premised on the rigorous adherence to deployment, training, and maintenance schedules. However, we reported in May 2016 on the difficulty that both the public and private shipyards were having in completing maintenance on time. We reported that, from 2011 through 2014, about 28 percent of scheduled maintenance for surface combatants was completed on time and 11 percent was completed on time for aircraft carriers. We updated these data as of November 2018 to include maintenance periods completed through the end of fiscal year 2018 and found that the Navy continues to struggle to complete maintenance on time. For fiscal years 2012-2018, our analysis for key portions of the Navy fleet shows that 30 percent of Navy maintenance was completed on time, leading to more than 27,000 days in which ships were delayed and unavailable for training and operations as shown in figure 2 below. In addition to affecting training and operations, maintenance delays are costly. In November 2018, we examined attack submarine maintenance delays and reported that the Navy was incurring significant operating and support costs to crew, maintain, and support attack submarines that are delayed getting into and out of shipyard maintenance periods. We estimated that over the past 10 years the Navy has spent $1.5 billion in fiscal year 2018 constant dollars to support attack submarines that provide no operational capability—those sitting idle no longer certified to conduct normal operations—while waiting to enter the shipyards, and those delayed in completing their maintenance at the shipyards (see figure 3). We recommended that the Navy analyze how it allocates its maintenance workload across public and private shipyards. DOD concurred with our recommendation, stating that it has taken the first steps to take a more holistic view of submarine maintenance requirements and impacts across both the public and private shipyards. In an update provided in November 2018, the Navy told us that they are developing a contracting strategy to conduct two additional depot maintenance periods at private shipyards in the future. Our prior work has shown that three primary factors at the naval shipyards contribute to maintenance delays: Poor conditions and aging equipment limit the ability of the shipyards to meet current and future demands. We reported in September 2017 that facility and equipment limitations at the shipyards contributed to maintenance delays for the aircraft carriers and submarines, hindering the shipyards’ ability to support the Navy. Specifically, we found that the shipyards would be unable to support an estimated one-third of maintenance periods planned over the next 23 years. We recommended that the Navy take steps to improve its management of shipyard investments; the Navy concurred with this recommendation and we are encouraged by its response. For example, the Navy has developed a plan for the optimal placement of facilities and major equipment at each public shipyard, which the Navy estimates can ultimately increase its maintenance efficiency by reducing personnel and materiel travel by an average of 65 percent. This equates to recovering about 328,000 man days per year—an amount roughly equal to that of an aircraft carrier maintenance period. However, the Navy’s preliminary estimate —that this effort will require an estimated $21 billion and 20 years to address—is well beyond historical funding levels, and does not include some potentially significant costs (e.g., for utilities, roads, or environmental remediation). Shipyard workforce gaps and inexperience are limiting factors. The Navy has reported a variety of workforce challenges at the Navy’s four public shipyards such as hiring personnel in a timely manner and providing personnel with the training necessary to gain proficiency in critical skills. The Navy has noted that some occupations require years of training before workers become proficient. According to Navy officials, a large portion of its workforce is inexperienced. For example, 45 percent of the Puget Sound and 30 percent of the Portsmouth Naval Shipyards’ skilled workforce have fewer than 5 years of experience. According to DOD officials, workforce shortages and inexperience contribute to maintenance delays. For example, at Pearl Harbor Naval Shipyard, two submarines were delayed approximately 20 months, in part because of shortages in ship fitters and welders, among other skilled personnel. Most of DOD’s depots, which include the naval shipyards, have taken actions to maintain critical skills through retention incentives, bonuses, and awards. We plan to issue a report examining DOD’s depot skill gaps, including those at the naval shipyards, later this month. Depot supply support may not be cost-effective. In June 2016, we reported that the naval shipyards and other depots had not implemented actions that would likely improve the cost-effectiveness of their supply operations. Specifically, the Navy had not transferred certain functions to the Defense Logistics Agency (DLA) at the shipyards in the same manner as the Navy and Air Force did for their aviation depots. The Navy and Air Force aviation depots that transferred these functions to DLA had reaped a number of efficiencies in their supply operations, including a 10-percent reduction in backorders over a 5-year period. We recommended that the Navy analyze whether such a transfer of functions is warranted at the shipyards and the Navy concurred with the recommendation. However, as of October 2018, the Navy had not conducted a comprehensive analysis of transferring these functions and had provided no plans to do so. In May 2017, we reported that the Navy’s process for determining manpower requirements—the number and skill mix of sailors needed on the Navy’s ships—did not fully account for all ship workload. The Navy was using outdated standards to calculate the size of ship crews that may have been leading to overburdened crews working long hours. We recommended steps to help ensure the Navy’s manpower requirements meet the needs of the existing and future surface fleet, and the Navy has been studying ship workload and revising its guidance. As of November 2018, the Navy was continuing to analyze the manpower requirements of its ship classes to better size and compose ship crews, and the Navy was also working to improve shipboard manning. However, these efforts are not yet complete and it is too early to assess their effectiveness. Until manpower requirements are reassessed across the fleet, the Navy risks that ship crews will continue to be undersized and sailors will be overworked with potential negative effects on readiness and safety. Additionally, the Navy provided information in November 2018 that showed that it is taking steps to ensure that ships have a minimum percentage of crew assigned and with the appropriate skills. The Navy has prioritized manning its surface ships homeported overseas. The Navy established a minimum threshold of filling at least 95 percent of authorized billets in its ship crews with sailors (referred to as fill), with a minimum goal of 92 percent of those sailors having the right qualifications for the billet (known as fit). According to Navy officials, the Navy is for the most part meeting its fill goals Navy-wide, but has not consistently met its fit goals. However, during group discussions in November 2018 with ship crews and interviews with Navy officials in Japan, we learned that the Navy’s methods for tracking fit and fill do not account for sailor experience and may be inaccurately capturing the actual presence of sailors onboard and available for duty on its ships. Moreover, sailors consistently told us that ship workload has not decreased, and it is still extremely challenging to complete all required workload while getting enough sleep. Navy officials told us that manning challenges will continue through at least fiscal year 2021 as the Navy increases its end strength and trains its new sailors to gain the proper mix of skills to operate and maintain the fleet. To meet continued operational demands, the Navy is planning for the most significant fleet size increase in over 30 years. According to the Navy’s fiscal year 2019 shipbuilding plan, the Navy plans to build and maintain a fleet of 355 battle force ships—an increase of about 25 percent above the Navy’s current force of 287 ships. To reach its goal, the Navy plans to buy 301 ships through 2048 and extend the service life of its 66 Arleigh Burke class destroyers and up to 7 attack submarines. Together, the fiscal year 2019 shipbuilding plan and the service life extensions would allow the Navy to reach a 355-ship fleet by the 2030s. Congressional Budget Office reporting and our past work have shown that the Navy has consistently and significantly underestimated the cost and timeframes for delivering new ships to the fleet. For example, the Navy estimates that buying the new ships specified in the fiscal year 2019 plan would cost $631 billion over 30 years while the Congressional Budget Office has estimated that those new ships would cost $801 billion—a difference of 27 percent. We also reported in June 2018 that acquisition outcomes for ship classes built during the last 10 years have often not achieved cost, schedule, quality, or performance goals that were established. Furthermore, we have reported that: all 8 of the lead ships delivered over the past decade that we reviewed were provided to the fleet behind schedule, and more than half of those ships were delayed by more than 2 years, and six ships of different classes valued at $6.3 billion were delivered to the Navy with varying degrees of incomplete work and quality problems. As a result of past cost and schedule problems, our work has shown that the Navy has a less-capable and smaller fleet today than it planned over 10 years ago. The Navy has also received $24 billion more in funding than it originally planned in its 2007 long-range shipbuilding plan but has 50 fewer ships in its inventory today, as compared with the goals it first established. Therefore, we have reported that as the Navy moves forward in implementing its shipbuilding plan it will be paramount for the Navy to learn from and apply lessons learned from the past. In addition to the cost of buying the ships and submarines to expand fleet size, the Navy will likely face affordability challenges with regard to the manning of an expanded fleet with the right number of sailors with the right mix of skills. In May 2017, we reported that the personnel costs for surface ship classes in fiscal years 2000-2015 were the largest share of total operating and support costs and that careful planning will be needed as new ships are brought into the fleet. We also reported that crew sizes on recently inducted ship classes grew from original projections as the Navy gained experience operating them. For example, the total crew size of Littoral Combat Ships has grown from 75 in 2003 to 98 personnel in 2016, a 31-percent increase. Navy officials told us that they plan to better articulate the personnel and resources needed for a larger fleet after fully accounting for workload and right-sizing ship crews. The Navy’s end strength has since increased by over 11,000 personnel from fiscal year 2017 levels, which should help alleviate manning challenges as the fleet grows. In November 2018, officials from Fleet Forces Command provided us with projections of its manning shortfalls continuing through at least fiscal year 2021 and steps it was planning to take to mitigate them. Our work has shown that Navy and Marine Corps aircraft availability has been limited by aging aircraft, delayed maintenance, and insufficient supply support. Pilot and maintenance personnel shortfalls further limit readiness recovery across legacy air platforms. The growing F-35 program, which is meant to replace many aging aircraft, has presented additional operational and sustainment challenges, which will likely persist into the future if not corrected. DOD, the Navy, and the Marine Corps have emphasized mission capability of critical aviation platforms— including the Navy and Marine Corps F/A-18s and F-35s—and are taking steps to improve availability, but these efforts will take time to realize results. Navy and Marine Corps aircraft availability has been limited by challenges associated with aging aircraft fleets, depot maintenance, and supply support challenges that limit the services’ ability to keep aviation units ready. The Navy and Marine Corps spend billions of dollars each year on sustainment, such as for spare parts and depot maintenance, to meet aircraft availability goals. However, aircraft availability rates have generally declined since fiscal year 2011. While specific aircraft availability data are considered sensitive by the Navy and the Marine Corps, and cannot be discussed in detail, we found in September 2018 that the Navy and the Marine Corps generally did not meet aircraft availability goals in fiscal years 2011-2016 for the seven aircraft we reviewed. In updating data in November 2018, we found that none of the aircraft met aircraft availability goals for fiscal years 2017 and 2018. According to the Navy, the pace of operations has increased wear and tear on its aircraft and decreased the time available for maintenance and modernization—a necessity for an aging fleet. For example, the average age of a legacy F/A-18A-D Hornet is 26 years, of an AV-8B Harrier is 21 years, and of the C-2A Greyhound is 29 years. Both services expect these aircraft will continue to be used for the foreseeable future and in some cases into the 2030s. The Navy and the Marine Corps face delays in the arrival of the F-35 to replace their legacy F/A-18A-D Hornets and AV-8B Harriers. To compensate for the delay, the Navy and the Marine Corps are planning to procure additional aircraft, such as the F/A-18E-F Super Hornet, and extend the service life and upgrade the capabilities of their legacy aircraft. However, these efforts and the sustainment of the Navy and Marine Corps legacy aircraft fleet face key challenges as shown in figure 4. Specifically, our prior work has shown that the Navy and the Marine Corps are confronted with two sets of challenges in sustaining their aircraft: Depot maintenance complexities for aging aircraft and spare parts availability. Depot maintenance on aging weapon systems, including Navy and Marine Corps aircraft, becomes less predictable as structural fatigue occurs and parts that were not expected to be replaced begin to wear out. While the Navy and the Marine Corps reported that sustainment funding accounts, such as those for depot maintenance and spare parts, have been funded at increased levels in fiscal years 2017 and 2018, efforts to improve spare parts availability take time to produce results due to long lead times for acquiring some items. In addition, Navy and Marine Corps aircraft face challenges associated with diminishing manufacturing sources and parts obsolescence. DOD has a program intended to manage these risks, but we reported in September 2017 that its implementation varied across DOD weapon system program offices. We made recommendations to improve the program’s management; DOD concurred and has initiated improvement efforts. Maintenance personnel inexperience and retention. The Navy has had difficulty attracting and retaining skilled maintainers, such as sheet metal workers and machinists at its aviation depots (i.e., Fleet Readiness Centers), which directly affects its ability to complete planned maintenance. Some of the depots experienced challenges attracting and retaining skilled personnel due to competition with nearby contractors that are able to offer higher pay, according to Navy depot officials. Similar to the shipyards, the aviation depots also lack experienced personnel, affecting the efficiency and quality of maintenance. For example, 41 percent of the skilled workers at Fleet Readiness Center Southwest have 2 years or fewer of experience. Workforce inexperience and attrition of skilled personnel were some of the reasons cited for machining defects detected in the landing gear for F/A-18, E-2, and C-2A aircraft by a recent Navy report. All of the depots have undertaken retention efforts such as incentives, bonuses, and awards to address these issues. Until the Navy and Marine Corps address maintenance and supply challenges it will be difficult to meet Secretary of Defense-established mission capability goals. Specifically, in September 2018, the Secretary of Defense issued a memorandum emphasizing that a key component of implementing the 2018 National Defense Strategy is ensuring critical aviation platforms meet their mission capability targets by the end of fiscal year 2019. The memorandum established a goal of achieving a minimum of 80-percent mission capable rates for various aircraft, including for the Navy’s and Marine Corps’ F/A-18 inventories, by the end of fiscal year 2019 while also reducing operating and maintenance costs. To accomplish this, the Navy and the Marine Corps developed the Return to Readiness strategy in November 2018 that includes a broad array of actions to improve the availability of spare parts and evaluate the application of best commercial practices to naval aviation sustainment, among other actions. Office of the Secretary of Defense and Navy program officials told us, and based on our prior work we agree, that this goal will be challenging to achieve by the end of fiscal year 2019. We reported in April 2018 that fighter pilot shortages in the Navy and the Marine Corps have been worsening in recent years and shortfalls are projected to remain through at least fiscal year 2023. Our analysis of Navy and Marine Corps data showed that the Navy’s shortage of first operational tour fighter pilots more than doubled from 12 percent in fiscal year 2013 to 26 percent in fiscal year 2017. Similarly, the Marine Corps’ overall shortage of fighter pilots quadrupled from 6 percent in fiscal year 2006 to 24 percent in fiscal year 2017. Also, as we reported in April 2018, service officials attributed the pilot shortages to reduced training opportunities and increased attrition due to career dissatisfaction, among other factors. Officials from both services stated at the time that they have ensured that deploying squadrons have been fully staffed with fighter pilots by using various approaches including using senior pilots to staff junior positions and having pilots deploy more frequently and for longer periods. However, we reported that squadron leaders and fighter pilots said that these approaches had a negative impact on the fighter pilot training and retention and ultimately may be exacerbating the situation. Further compounding their pilot shortages, we also found that the services have not recently reevaluated squadron requirements to reflect an increased fighter pilot workload. As a result, the reported shortage actually could be greater. The services were taking actions, including increasing retention incentives for fighter pilots. To help determine the magnitude of the shortages and help target strategies to better meet their personnel needs, we recommended, and the Navy and Marine Corps agreed, to reevaluate fighter pilot squadron requirements. Sustainment challenges are not just an issue for older aircraft, but represent an enduring challenge for the F-35 Lightning II aircraft—a key component to the future of tactical aviation for the Navy and Marine Corps. The Navy and Marine Corps are both flying F-35s now as the program ramps up development, and they plan to procure nearly 700 aircraft over the coming decades. The sustainment costs of the F-35 fleet are projected to exceed $1 trillion over its 60-year life cycle. In October 2017, we reported that: F-35B aircraft (including Marine Corps aircraft) were available (i.e., the aircraft were safe to fly, available for use, and able to perform at least one tasked mission) about 52 percent of the time from March 2017 through June 2017, which fell short of the 65-percent goal established by the Marine Corps for non-deployed units and F-35B aircraft (including Marine Corps aircraft) were fully mission capable (i.e., the aircraft were capable of accomplishing all tasked missions) about 15 percent of the time from March 2017 through June 2017, which fell short of the 60-percent goal established by the Marine Corps for non-deployed units. We also reported on numerous sustainment challenges leading to less than desirable outcomes for F-35 warfighter readiness. For example, F-35 aircraft were unable to fly 22 percent of the time because of parts shortages from January 2017 through August 7, 2017. Additionally, DOD’s capabilities to repair F-35 parts at military depots were 6 years behind schedule, which resulted in average part repair times that are twice that of the program’s objective. As DOD gains experience with the F-35, our work has shown that the department has encountered additional challenges. In 2017, the Marine Corps became the first military service to station F-35 aircraft overseas, transferring aircraft to Iwakuni, Japan. While in the Pacific, DOD expects to disperse its F-35s into smaller detachments to outmaneuver the enemy and counter regional threats. However, in April 2018, we reported that this approach posed logistics and supply challenges. In June 2018, we reported that the F-35 program had not improved its reliability and maintainability over the past year and continued to fall short on half of its performance targets. Furthermore, we found that the program may not meet its required targets before each variant of the F-35 is expected to demonstrate maturity—the point at which the aircraft has flown enough hours to predictably determine reliability and maintainability over its lifespan. This means that the Navy and the Marine Corps may have to decide whether they are willing to accept less reliable and maintainable aircraft than originally planned. Among other outcomes, this could result in higher maintenance costs and lower aircraft availability than anticipated which also could pose readiness challenges in the future. As we reported in October 2017, the poor reliability of certain parts is already contributing to shortages of F-35 spare parts. Challenges posed by the F-35 program are largely the result of sustainment plans that do not fully include or consider key requirements. Our work has shown that planning for sustainment and aligning its funding are critical if DOD wants to meet its aircraft availability goals and effectively deploy to support operations. To address the challenges associated with F-35 sustainment and operational deployment, we recommended that DOD revise its sustainment plans, align associated funding, and mitigate the risks associated with key supply chain-related challenges for deployed F-35s in the Pacific, among others. DOD concurred with these recommendations and stated that it is taking steps to address them. Furthermore, as previously discussed, the Secretary of Defense has established an 80-percent mission capability goal for critical aviation assets, including the F-35. Due to current low availability and numerous sustainment issues, the F-35 fleet will be challenged in meeting the goal. In sum, the Navy’s and Marine Corps’ significant readiness challenges have developed over more than a decade of conflict, budget uncertainty, and reductions in force structure. Both services have made encouraging progress identifying the causes of their readiness decline and have begun efforts to arrest and reverse it; however, our prior work shows that fully addressing the persistent readiness challenges will require years of sustained management attention. Our work cited today contains 25 specific recommendations to the Navy and the Marine Corps and an additional 20 recommendations to various other DOD components to assist these services in rebuilding the readiness of their forces and in modernizing for the future. Attention to these recommendations can assist the Navy and the Marine Corps as they seek to rebuild the readiness of their forces. Chairmen Wicker and Sullivan, Ranking Members Hirono and Kaine, and Members of the Subcommittees, this concludes my prepared statement. I would be pleased to respond to any questions you may have at this time. If you or your staff have questions about this testimony, please contact John H. Pendleton, Director, Defense Capabilities and Management at (202) 512-3489 or pendletonj@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this statement. GAO staff who made key contributions to this testimony are Suzanne Wren, Assistant Director; Clarine Allen; Steven Banovac; John Bumgarner; Chris Cronin; Benjamin Emmel; Cynthia Grant; Mae Jones; Amie Lesser; Tobin McMurdie; Shahrzad Nikoo; Carol Petersen; Cody Raysinger; Michael Silver; John E. “Jet” Trubey; and Chris Watson. Over the past 4 years, we have issued a number of reports related to Navy and Marine Corps readiness and we used them to develop this statement. Table 1 summarizes the recommendations in these reports. The Department of Defense (DOD) concurred with most of the 45 recommendations and has many actions underway. However, DOD has not fully implemented any of the recommendations to date. For each of the reports, the specific recommendations and any progress made in implementing them are summarized in tables 2 through 16. Report numbers with a C or RC suffix are classified. Report numbers with a SU suffix are sensitive but unclassified. Classified and sensitive but unclassified reports are available to personnel with the proper clearances and need to know, upon request. Navy Readiness: Actions Needed to Address Costly Maintenance Delays Facing the Attack Submarine Fleet. GAO-19-229. Washington, D.C.: November 19, 2018. Air Force Readiness: Actions Needed to Rebuild Readiness and Prepare for the Future. GAO-19-120T. Washington, D.C.: October 10, 2018. Weapon System Sustainment: Selected Air Force and Navy Aircraft Generally Have Not Met Availability Goals, and DOD and Navy Guidance Need to Be Clarified. GAO-18-678. Washington, D.C.: September 10, 2018. Weapon System Sustainment: Selected Air Force and Navy Aircraft Generally Have Not Met Availability Goals, and DOD and Navy Guidance Need Clarification. GAO-18-146SU. Washington, D.C.: April 25, 2018. Military Readiness: Update on DOD’s Progress in Developing a Readiness Rebuilding Plan. GAO-18-441RC. Washington, D.C.: August 10, 2018. (SECRET) Military Personnel: Collecting Additional Data Could Enhance Pilot Retention Efforts. GAO-18-439. Washington, D.C.: June 21, 2018. F-35 Joint Strike Fighter: Development Is Nearly Complete, but Deficiencies Found in Testing Need to Be Resolved. GAO-18-321. Washington, D.C.: June 5, 2018. Warfighter Support: DOD Needs to Share F-35 Operational Lessons Across the Military Services. GAO-18-464R. Washington, D.C.: April 25, 2018. Military Readiness: Clear Policy and Reliable Data Would Help DOD Better Manage Service Members’ Time Away from Home. GAO-18-253. Washington, D.C.: April 25, 2018. Military Personnel: DOD Needs to Reevaluate Fighter Pilot Workforce Requirements. GAO-18-113. Washington, D.C.: April 11, 2018. Military Aircraft: F-35 Brings Increased Capabilities, but the Marine Corps Needs to Assess Challenges Associated with Operating in the Pacific. GAO-18-79C. Washington, D.C.: March 28, 2018. (SECRET) Navy and Marine Corps Training: Further Planning Needed for Amphibious Operations Training. GAO-18-212T. Washington, DC.: December 1, 2017. F-35 Aircraft Sustainment: DOD Needs to Address Challenges Affecting Readiness and Cost Transparency. GAO-18-75. Washington, D.C.: October 26, 2017. Defense Supply Chain: DOD Needs Complete Information on Single Sources of Supply to Proactively Manage the Risks. GAO-17-768. Washington, D.C.: September 28, 2017. Navy and Marine Corps Training: Further Planning Needed for Amphibious Operations Training. GAO-17-789. Washington, D.C.: September 26, 2017. Navy Readiness: Actions Needed to Address Persistent Maintenance, Training, and Other Challenges Facing the Fleet. GAO-17-809T. Washington, D.C.: September 19, 2017. Naval Shipyards: Actions Needed to Improve Poor Conditions That Affect Operation. GAO-17-548. Washington, D.C.: September 12, 2017. Navy Readiness: Actions Needed to Address Persistent Maintenance, Training, and Other Challenges Facing the Fleet. GAO-17-798T. Washington, D.C.: September 7, 2017. Navy Readiness: Actions Needed to Maintain Viable Surge Sealift and Combat Logistics Fleets GAO-17-503. Washington, D.C.: August 22, 2017 (reissued on Oct 31, 2017). Department of Defense: Actions Needed to Address Five Key Mission Challenges. GAO-17-369. Washington, D.C.: June 13, 2017. Military Readiness: Coastal Riverine Force Challenges. GAO-17-462C. Washington, D.C.: June 13, 2017. (SECRET) Navy Shipbuilding: Policy Changes Needed to Improve the Post-Delivery Process and Ship Quality. GAO-17-418. Washington, D.C.: July 13, 2017 Offshore Petroleum Discharge System: The Navy Has Not Mitigated Risk Associated with System Limitations. GAO-17-531C. Washington, D.C.: June 22, 2017. (SECRET) Navy Force Structure: Actions Needed to Ensure Proper Size and Composition of Ship Crews. GAO-17-413. Washington, D.C.: May 18, 2017. Military Readiness: DOD’s Readiness Rebuilding Efforts May Be at Risk without a Comprehensive Plan. GAO-16-841. Washington, D.C.: September 7, 2016. Military Readiness: DOD’s Readiness Rebuilding Efforts May Be at Risk without a Comprehensive Plan. GAO-16-534C. Washington, D.C.: June 30, 2016. (SECRET) Defense Inventory: Further Analysis and Enhanced Metrics Could Improve Service Supply and Depot Operations. GAO-16-450. Washington, D.C.: June 9, 2016. Navy and Marine Corps: Services Face Challenges to Rebuilding Readiness. GAO-16-481RC. Washington, D.C.: May 25, 2016. (SECRET//NOFORN) Military Readiness: Progress and Challenges in Implementing the Navy’s Optimized Fleet Response Plan. GAO-16-466R. Washington, D.C.: May 2, 2016. F-35 Sustainment: DOD Needs a Plan to Address Risks Related to Its Central Logistics System. GAO-16-439. Washington, D.C.: April 14, 2016. Navy Force Structure: Sustainable Plan and Comprehensive Assessment Needed to Mitigate Long-Term Risks to Ships Assigned to Overseas Homeports. GAO-15-329. Washington, D.C.: May 29, 2015. This is a work of the U.S. government and is not subject to copyright protection in the United States. The published product may be reproduced and distributed in its entirety without further permission from GAO. However, because this work may contain copyrighted images or other material, permission from the copyright holder may be necessary if you wish to reproduce this material separately.

Answer: The 2018 National Defense Strategy emphasizes that restoring and retaining readiness is critical to success in the emerging security environment. The Navy and Marine Corps are working to rebuild the readiness of their forces while growing and modernizing their aging fleet of ships and aircraft. However, achieving readiness recovery goals will take years as both services continue to be challenged to rebuild readiness amid continued operational demands. This statement provides information on current and future readiness challenges facing (1) the Navy ship and submarine fleet and (2) Navy and Marine Corps aviation. GAO also discusses prior recommendations on Navy and Marine Corps readiness and progress to address them. This statement is based on previously published work since 2015 related to Navy and Marine Corps readiness challenges, including shipyard workforce and capital investment, ship crewing, weapon system sustainment, the fighter pilot workforce, and modernizing force structure. GAO conducted site visits to the Pacific fleet in November 2018 and analyzed updated data, as appropriate. The Navy has taken steps to address training shortfalls in the surface fleet, but faces persistent maintenance and personnel challenges as it seeks to rebuild ship and submarine readiness. While the Navy has corrective actions underway, they will take years to implement. Following ship collisions in 2017, the Navy has taken steps to ensure its crews are trained to standards prior to deployment and made significant progress in those efforts. However, the Navy has struggled to complete ship maintenance—with only 30 percent of maintenance completed on time since fiscal year 2012—leading to thousands of days that ships were unavailable for training and operations (see figure). Additionally, manning shortfalls and experience gaps continue to contribute to high sailor workload and are likely to continue through at least fiscal year 2021. The Navy has developed a plan to improve shipyards and is re-examining its ship manning, among other actions; however, these positive steps have not yet fully addressed GAO's recommendations. Looking to the future, the Navy has indicated that it wants to grow its fleet to meet demands. However, the costs of such growth are not yet known and would likely require resourcing well above currently planned levels. Navy and Marine Corps aircraft availability has been limited due to numerous challenges (see figure). Specifically, the seven aircraft GAO reviewed have generally experienced decreasing availability since fiscal year 2011 and did not meet availability goals in fiscal years 2017 and 2018. The F-35—the future of naval aviation—also has not met availability goals due to part shortages and poor sustainment planning. In September 2018, the Department of Defense established aggressive targets for aircraft availability. While the Navy and Marine Corps are taking actions to improve aircraft availability, including addressing GAO's recommendations, aviation readiness will take many years to recover. GAO has made a total of 45 recommendations in the prior work described in this statement. The Department of Defense concurred with most of them, and has many actions underway, but has not yet fully implemented any. Attention to these recommendations can assist the Navy and the Marine Corps as they seek to rebuild the readiness of their forces.