The maintenance and logistics support system for the F-35 Lightning II is about two-thirds of the way toward completion, but it will initially operate without a planned data link capability that would enable the fighter to transmit information to the ground while airborne. The so-called Prognostics and Health Management downlink has been deferred for later development to better secure the data stream, according to the Pentagon’s F-35 Joint Program Office (JPO).

Prime contractor Lockheed Martin has introduced the second of three major software releases it will deliver for the Autonomic Logistics Information System (ALIS) that will support U.S. and international F-35s once they are fielded. The company describes ALIS as the “operations management backbone,” of the fifth-generation fighter, an information technology infrastructure that captures and analyzes health and maintenance data for individual airframes as well as for the larger fleet. The system is designed to support F-35 operations, maintenance, fault prognostics and parts deliveries over the lifecycle of the fighter, providing maintainers with timely information over a distributed network.

The system’s third major software release is planned in 2017 with the conclusion of the F-35 system development and demonstration phase.

At least initially, ALIS will operate without the radio frequency downlink that would enable the F-35 to send health monitoring data to the ground while the fighter is airborne. The system now saves information to a data storage device on the aircraft. When the fighter lands, the pilot takes the data storage device to a maintenance control facility, where the data is extracted.

In a recent interview with AIN, Jeff Streznetcky, Lockheed Martin’s ALIS program director, said deferring development of the Prognostics Health Management downlink was “a joint decision” of Lockheed Martin and the government, but he referred questions to the JPO.

The JPO provided the following statement: “The Prognostics and Health Management data downlink provides F-35 maintainers with an advanced look into aircraft diagnostics, consumables and weapons status prior to landing. Testing of the downlink revealed the need to upgrade it with enhanced security measures. Those improvements will be completed in follow-on development; specific timelines for all Block 4 capabilities are under program review. The downlink has no bearing on the aircraft’s diagnostics performance. The same information can be obtained once the F-35 lands.”