Weapon System Sustainment: Various Challenges Affect Ground Vehicles' Availability for Missions

Mission Capable Rates Trends for Selected Army and Marine Corps Ground Vehicles

Five of six selected Army ground combat vehicles did not meet mission capable goals in any fiscal year (FY) during the time frame of GAO's review. In the same time frame, selected Army ground support vehicles achieved mission capable goals about 20 percent of the time. The Marine Corps does not have a mission capable goal for its ground vehicles, though two of seven selected vehicles achieved positive changes in mission capable rates when comparing fiscal years 2015 and 2024.

Number of Years That Army Ground Vehicles Met Mission Capable Goals in Fiscal Years 2015 through 2024

Sustainment Challenges Affecting Army and Marine Corps Ground Vehicles

Nine sustainment challenges have affected the ground vehicle fleets as shown in the figure on the next page. According to Army and Marine Corps officials, two challenges affected all 18 ground vehicles in this review: a lack of parts and materiel and not having current technical data or drawings. Further, other sustainment challenges that affected many ground vehicles included a shortage of trained or skilled maintainers, service-life issues, and unplanned maintenance.

GAO found that the number of overhauls performed by Army depots dropped from 1,278 in FY 2015 to 12 in FY 2024. A senior Army official stated that the Army accepted the risk from the decision to reduce funding for overhauls. Army officials also said reducing overhauls negatively affected the mission capable rates of most vehicles. Further, the Army partially mitigated declining overhauls by harvesting parts from vehicles being phased out of service. Also, the Marine Corps reduced the number of depot overhauls from 725 in FY 2015 to 163 in FY 2024. Marine Corps officials said they have not begun performing overhauls on two recently fielded vehicles and stopped performing overhauls on two others it is phasing out of service.

Army and Marine Corps Identified Sustainment Challenges Affecting Selected Ground Vehicles

Even as mission capable rates and depot overhauls have declined, the cost of maintaining Army and Marine Corps vehicles has gone up for most selected ground vehicles. Since FY 2015, GAO found the Army's maintenance costs increased for 9 of the 11 ground vehicles in GAO's review. For example, when comparing FY 2015 to FY 2023, the Abrams experienced a fleet-wide increase in maintenance costs of $181.3 million and per-vehicle maintenance costs nearly doubled. Meanwhile, availability rates were below the Army's goal. The Marine Corps' fleet-wide maintenance costs decreased, although its per-vehicle maintenance costs increased for four of seven vehicles in GAO's review.

Why This Matters

The Department of Defense (DOD) spends billions of dollars annually to sustain its weapon systems, including ground vehicles, to ensure that these systems are available to support defense requirements. In FY 2023, the Army and Marine Corps spent more than $2.3 billion combined on depot maintenance of their ground vehicles. Ground vehicles are one type of weapon system sustained by DOD to conduct their missions. Weapon systems are costly to sustain, in part, because they often incorporate a complex array of technical subsystems and components and need expensive repair parts and logistics support to meet required readiness levels.

How GAO Did This Study

For the 18 selected Army and Marine Corps ground vehicles that provide combat and support roles, this report examines vehicle availability rates in FY 2024, the types of sustainment challenges affecting ground vehicles, and maintenance costs. GAO performed site visits to Army and Marine Corps depots, interviewed cognizant officials, collected and analyzed data about mission capable rates and cost, among other things, and determined the data were sufficiently reliable for the purposes of this review. Further, GAO collected information on what actions the services have taken to address the sustainment challenges. This is a public version of a sensitive report GAO issued in August 2025. GAO omitted information that DOD deemed Controlled Unclassified Information.

For more information, please contact Director Diana Maurer at [email protected].