A review conducted by the US Government Accountability Office (GAO) has recommended that the US Department of Defense (Dod) must address the challenges affecting readiness and cost transparency of the F-35 Lightning II Joint Strike Fighter sustainment programme.

The DoD is sustaining more than 250 F-35 aircraft, with plans to triple the fleet by the end of 2021.

The GAO found that the DoD’s capabilities to repair F-35 parts at military depots are six years behind schedule.

Other challenges affecting the fighter aircraft’s readiness include spare parts shortages, undefined technical data needs, unfunded intermediate-level maintenance capabilities and delays in autonomic logistics information system (Alis) development and uncertain funding.

From January to 7 August, the F-35 aircraft were unable to fly more than 22% of the time due to parts shortages.

The DoD has not defined all of the technical data it needs from the prime contractor.

The ALIS is a complex system that has been designed to support operations and maintenance that is key to F-35 sustainment.

“F-35 aircraft were unable to fly more than 22% of the time due to parts shortages.”

Planned updates to ALIS will likely be delayed and requirements for the system development are not fully funded, according to GAO.

GAO has recommended that the Under Secretary of Defense for Acquisition, Technology, and Logistics must revise sustainment plans to ensure that they include the key requirements and decision points required to fully implement the F-35 sustainment strategy and aligned funding plans to meet those requirements.

The DoD must also re-examine the metrics that it will use to hold the contractor accountable under the fixed-price, performance-based contracts.

It must focus on improving communication with the services and provide more information about how the F-35 sustainment costs they are being charged relate to the capabilities received.