Ship maintenance

Navy Vessel Maintenance: Actions Needed to Monitor and Manage Performance of Intermediate Maintenance Periods

What the GAO found

The Navy collected, but did not analyze, limited data on the performance of interim maintenance periods – work often occurring while a ship is docked and able to start within 96 hours. Based on this data, the GAO found that the Navy completed 191 of 414 (46%) overdue submarine interim maintenance periods from fiscal years 2015 through 2020, totaling 2,525 days of maintenance overdue. The Navy failed to collect several categories of data for submarines, surface ships and aircraft carriers, including planned and actual maintenance costs. Without establishing and implementing procedures to collect and analyze this data, the Navy cannot effectively track and improve the performance of interim maintenance periods.

The GAO has identified four key challenges affecting the performance of interim maintenance periods for submarines, surface ships, and aircraft carriers based on discussions with ship crews and Navy organization officials (see fig.).

Four main challenges affecting the performance of interim maintenance periods

Ships’ crews and shore-based maintenance providers have taken steps to address these challenges, but have had limited success because the Navy’s efforts have been fragmented, have generally not included the sharing of best practices and lessons learned, and did not include the performance of interim maintenance periods in its strategic planning. For example:

  • The Navy’s carrier community independently established a task force to address some aspects of parts shortages, but did not share this effort with the entire fleet. The establishment of a mechanism for sharing best practices and feedback will enable the Navy to better respond to the issues affecting the execution of these maintenance periods.
  • The Navy has not included the execution of interim maintenance windows for submarines, surface ships and aircraft carriers in strategic planning efforts. Without considering the performance of the interim maintenance periods in its strategic planning and related initiatives, the Navy risks negatively affecting the readiness of the fleet.

Addressing these issues will better position the Navy to increase the readiness of the submarines, surface ships, and aircraft carriers needed to accomplish their missions.

Why GAO Did This Study

In fiscal years 2015 through 2020, the Navy spent an average of $2.1 billion a year performing high-priority maintenance on submarines, surface ships, and aircraft carriers. Navy ships’ crews and shore-based maintenance providers, located in homeports around the world, typically performed this maintenance – referred to by the GAO as “intermediate maintenance periods” – to prepare ships for start-up to run their next assignments.

The House Armed Services Committee, in a report accompanying a bill relating to the National Defense Authorization Act for fiscal year 2021, included a provision allowing the GAO to review interim maintenance periods for ships of the Marine. GAO assessed the extent to which the Navy (1) collected and used data regarding the performance of interim maintenance periods for submarines, surface ships, and aircraft carriers in fiscal years 2015 through 2020, and (2) addressed challenges affecting the performance of intermediate maintenance periods. The GAO analyzed data for the Navy’s interim maintenance periods during fiscal years 2015 through 2020, reviewed key documents, and met with aircrews and Navy officials.