April 26 (UPI) -- The lower-than-desired performance of the F-35 fighter plane is the result of supply chain issues, the General Accounting Office said in a report.
The 59-page report, released on Thursday, noted that the plane is unable to fly as often as required because of spare parts shortages and logistical problems in moving parts around the world.
GAO said that in the time period analyzed, May to November of 2018, F-35s were unable to fly 30 percent of the time because of shortages and mismatched parts, and that the Defense Department has an order backlog of about 4,300 parts.
Parts for the aircraft are made largely in the United States, but also in other NATO countries, and the report said the Defense Department has not fully determined which actions are required to close the pipeline gap between fighting requirements and the performance of the F-35 supply chain.
It noted that in one example, 44 percent of purchased parts were incompatible with F-35 planes in use by the U.S. Marine Corps. Without immediate adjustments to the "immature" supply chain, it said, U.S. planes will be regularly grounded, and foreign customers will experience significant delays for parts needed to repair aircraft.
The report offered eight major recommendations: a comprehensive review of the supply chain by the Undersecretary of Defense for Acquisition and Sustainment and other high-level Pentagon officials; development of a process for obtaining spare parts; prioritization of F-35 parts deliveries; development of an improved global parts network; an accountability protocol; better comprehensive cost information from prime contractors; better accounting of funds spent on F-35 parts, and a better strategy for management of the F-35 supply chain.
Lockheed Martin, the plane's developer, is also the contractor for the majority of its spare parts, and has numerous agreements with suppliers around the world. Last week, the company announced a series of deals with subcontractors it says will lower the cost of the F-35, as well as improve availability of parts.