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F-35 Aircraft Sustainment: DOD Faces Challenges in Sustaining a Growing Fleet

GAO-20-234T Published: Nov 13, 2019. Publicly Released: Nov 13, 2019.
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Fast Facts

The F-35 fighter plays a key role in U.S. defense strategy. As of October, the United States and international partners had fielded more than 435 of an expected 3,300 aircraft.

We testified that DOD faces challenges keeping the growing fleet ready to perform its mission, largely due to insufficient planning. Challenges include

Spare parts shortages: F-35s were unable to fly about 30% of the time due to a lack of spare parts from May-November 2018

Poor performance of the information technology system used to sustain the aircraft: It requires manual workarounds and has data inaccuracies

We have 21 open recommendations to address these issues.

A U.S. Marine Corps F-35B aboard the U.S.S. America

Military aircraft landing on an aircraft carrier in the ocean

Military aircraft landing on an aircraft carrier in the ocean

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What GAO Found

The Department of Defense (DOD) faces challenges in sustaining a growing F-35 fleet. This statement highlights three challenges DOD has encountered related to F-35 sustainment, based on prior GAO work (see figure).

Selected F-35 Sustainment Challenges

Selected F-35 Sustainment Challenges

As a result of these challenges, F-35 performance has not met warfighter requirements. While DOD works to address these issues, it must also grapple with affordability. DOD has determined that it will need to significantly reduce F-35 sustainment costs—by 43 percent per aircraft, per year in the case of the Air Force—in order for the military services to operate the F-35 as planned.

Continued attention to GAO's recommendations in these areas will be important as DOD takes actions to improve F-35 sustainment and aircraft performance for the warfighter.

Why GAO Did This Study

DOD's F-35 Lightning II fighter aircraft provides key aviation capabilities to support the U.S. National Defense Strategy. The F-35 is also DOD's most costly weapon system, with U.S. sustainment costs estimated at more than $1 trillion over its life cycle. As of October 2019, there were more than 435 U.S. and international F-35 aircraft in operation, with more than 3,300 aircraft expected to be fielded throughout the life of the program. While there is little doubt that the F-35 brings unique capabilities to the U.S. military, DOD faces significant challenges in sustaining a growing fleet.

This statement discusses F-35 sustainment challenges. It also summarizes GAO's open recommendations related to these challenges.

This statement is based on previously published work since 2014 related to F-35 acquisition, sustainment, affordability, ALIS, operations, and the global supply chain.


GAO has 21 recommendations related to the challenges described in this statement that DOD has not fully implemented. DOD generally concurred with all 21 recommendations. Continued attention to these recommendations is needed by DOD to successfully operate and sustain the F-35 fleet over the long term within budgetary realities.

Full Report

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Supply chain managementProprietary dataLogisticsActual costsAircraft acquisition programsAircraftJoint strike fighterSpare partsMilitary readinessPrime contractors