Military Depots: The Navy Needs Improved Planning to Address Persistent Aircraft Maintenance Delays While Air Force Maintenance Has Generally Been Timely

GAO-20-390 Published: Jun 23, 2020. Publicly Released: Jun 23, 2020.
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Fast Facts

Three Air Force and three Navy aviation depots maintain critical aircraft such as the KC-135 tanker and F/A-18 fighter. Delays at depots can reduce aircraft availability for operations and training.

We reviewed depot performance for selected aircraft over 6 years.

Air Force depots completed maintenance on-time or early in 5 of 6 years (with aircraft in maintenance 22,572 fewer days than expected)

Navy depots were late all 6 years (over 62,000 more days than expected)

We also identified Navy planning challenges, such as a need for more effective use of historical maintenance data. We made 3 recommendations to the Navy to reduce delays.

An F/A-18 undergoing depot maintenance at Fleet Readiness Center Southwest in San Diego.

Fighter plane in hangar

Fighter plane in hangar

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Highlights

What GAO Found

The Air Force and Navy varied in the extent that they completed depot maintenance on time for selected fixed-wing aircraft in fiscal years 2014 through 2019. Specifically, GAO's analysis of aggregate maintenance data found that:

Air Force depots completed aircraft maintenance on time or early in 5 of 6 years, with percentages for on-time or early-completion maintenance ranging from 78 to 90 percent.

Navy depots completed aircraft maintenance late for each of the 6 years, with percentages for on-time or early-completion maintenance ranging from 45 to 63 percent. Navy fixed-wing aircraft have spent over 62,000 more days in maintenance than expected since fiscal year 2014.

Aircraft Maintenance Completed On Time or Early by Service, Fiscal Years 2014 through 2019

highlights_5_v3_103529-01

The Air Force generally has accurately planned for depot maintenance requirements for selected fixed-wing aircraft during fiscal year 2014 through 2019, but the Navy has not. Both services have initiatives underway to improve planning for aviation depot maintenance; however, GAO identified planning challenges that the Navy has not fully addressed:

The Navy has not effectively used historical data to analyze turnaround time—total days planned for depot maintenance periods—and established accurate planning targets for aircraft maintenance packages.

Navy depot planners do not have visibility into aircraft maintenance that is performed outside the depots by an operational unit or other maintenance facility—information critical to planning for the condition and depot maintenance needs of individual aircraft.

The Navy does not yet have formal processes and related guidance for communication and coordination between depot stakeholders to inform maintenance requirements planning.

Without addressing these challenges, the Navy cannot appropriately plan for depot maintenance workload and will likely continue to experience maintenance delays that reduce the time aircraft are available for operations and training.

Why GAO Did This Study

Three Air Force and three Navy aviation depots maintain critical fixed-wing aviation platforms, such as the KC-135 aerial refuelers and F/A-18 fighters. The ability of these depots to complete maintenance on time directly affects military readiness because delays reduce the time aircraft are available for operations and training.

Senate Report 115-262, accompanying a bill for the Fiscal Year 2019 National Defense Authorization Act, contained provisions that GAO examine the Department of Defense's (DOD) aviation depots. GAO's report evaluates the extent to which 1) the Air Force and Navy aviation depots completed selected fixed-wing aircraft maintenance on time from fiscal year 2014 through 2019, and 2) the Air Force and Navy accurately planned for depot maintenance requirements from fiscal year 2014 through 2019 and addressed any associated challenges.

GAO selected a non-generalizable sample of 18 Air Force and 18 Navy fixed-wing aircraft types; analyzed maintenance and planning data for fiscal year 2014 through 2019; and interviewed service officials.

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Recommendations

GAO is making three recommendations to the Navy: to use historical data to set turnaround time targets for depot maintenance; provide planners information on maintenance performed outside the depots; and establish processes for communication between depot stakeholders. DOD concurred with all three recommendations.

Recommendations for Executive Action

Agency Affected Recommendation Status
Department of the Navy The Secretary of the Navy should ensure that Naval Air Systems Command and Commander, Fleet Readiness Centers effectively use historical data to analyze turnaround time and establish accurate turnaround time targets for fixed-wing aircraft depot maintenance packages. (Recommendation 1)
Closed – Implemented
The Navy concurred with our recommendation. In February 2022, the Navy provided documentation showing that the department has implemented the Naval Sustainment System for Aviation initiative across the F/A-18E-F, EA-18G, E-2D, MV-22, and CH-53E aircraft fleets. This initiative utilized both historical data and readiness goals to establish turnaround time targets to minimize Out of Reporting aircraft quantities. As a result, the Navy is now using realistic turnaround time targets for their fixed-wing aircraft depot maintenance packages.
Department of the Navy The Secretary of the Navy should ensure that Commander, Naval Air Forces and Commander, Naval Air Force, Pacific provide depot planners regular reporting on fixed-wing aircraft maintenance performed outside the Navy aviation depots by an operational unit or at an intermediate maintenance facility to ensure they have information on the current condition and depot maintenance needs of individual aircraft. (Recommendation 2)
Open
The Navy concurred with our recommendation. As of February 2022, the Navy has developed a requirements document for an IT system that is intended to unify and digitize data from the organizational, intermediate, and depot-levels. However, we are waiting confirmation on when this system will be fully operational to provide Navy depot planners regular reporting on fixed-wing aircraft maintenance performed outside the Navy aviation depots to ensure they have information on the current condition and depot maintenance needs of individual aircraft.
Department of the Navy The Secretary of the Navy should ensure that Naval Air Systems Command and Commander, Fleet Readiness Centers establish formal processes and related guidance for communication and coordination between depot stakeholders to inform maintenance requirements planning. (Recommendation 3)
Open
The Navy concurred with our recommendation. In February 2021, the Navy provided an estimated completion date of December 31, 2021, noting that Commander, Fleet Readiness Centers had initiated a depot planning process which involves all stakeholders and focuses on ensuring that the Navy has the required capacity to fulfill future maintenance requirements across all aviation platforms. In February 2022, the Navy provided an update stating that Formal Standard Work Packages (SWPs) and OPNAV level instructions are currently being reviewed related to the depot planning process. We are waiting to review the SWPs and OPNAV level instructions to ensure that it addresses the intent of our recommendation to establish formal processes and related guidance for communication and coordination. We will continue to monitor the implementation of these efforts for Navy fixed-wing aircraft.

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