RTX [RTX] began deliveries of its Next Generation Electro-Optical Distributed Aperture System (EO DAS) for the Lockheed Martin [LMT] F-35 fighter in January, as the F-35 program looks to use military personnel to help sustain the

Northrop Grumman [NOC] AN/AAQ-37 DAS, which the RTX EO DAS is to replace, and the Northrop Grumman AN/APG-81 active electronically scanned array radar.

The F-35 Joint Program Office declined to say whether the RTX Next Generation EO DAS has flown in any of the Technology Refresh 3 test flights thus far. Such flights to enable F-35 Block 4 began on Jan. 6 at Edwards AFB, Calif. (Defense Daily, Jan. 10).

The Next Generation EO DAS “was delivered and installed on multiple aircraft for flight test,” the F-35 JPO wrote in an Aug. 21 email response to questions. “Raytheon began Next Generation Electro-Optical DAS deliveries in January 2023 for installation on production aircraft.”

Among the challenges that the F-35 program and industry have said that they are addressing is a parts shortage for the Northrop Grumman [NOC] AN/AAQ-37 DAS, which is to provide 360 degree awareness for F-35 pilots from six infrared sensors that feed data to the pilot’s helmet (Defense Daily, Nov. 9, 2022).

Plans have called for the integration of the RTX Next-Generation EO DAS into all F-35s beginning this year with Lot 15 under TR-3.

Northrop Grumman bowed out of a bid for the AN/AAQ-37 follow-on program in 2018, as company executives said that the pay-off would be higher for other business opportunities.

Last fall, Northrop Grumman said that it is on contract “to deliver [AAQ-37] production units into 2023, and to support the system through sustainment contracts beyond that timeframe.”

The Air Force Sustainment Center’s branch office at Robins AFB, Ga., is considering a possible contract to provide engineering support for Initial Operational Capability (IOC) of the Operational Flight Programs of the APG-81 and the AAQ-37 DAS (Defense Daily, Aug. 11).

An Aug. 10 Request for Information‘s (RFI) Performance Work Statement (PWS) said that the latter would establish “government organic capability”  of the APG-81 and AAQ-37 for the Air Force’s 402nd Software Engineering Group at Robins “by providing data access to source code, technical data, software development environment and tools, and establishing testing capabilities at Robins Air Force Base.”

The F-35 JPO said on Aug. 21 that subtasks “include but are not limited to, sustainment, modernization, configuration/data management and transition planning.”

“The government’s need for this requirement is required in order to establish organic IOC pertaining to the F-35 radar and DAS,” the F-35 program said.

The Aug. 10 RFI said that Northrop Grumman “shall provide sufficient manpower for the investigation, development, integration, testing, and delivery of up to 24 Radar Deficiency Reports (DRs), up to 17 DAS DRs, and the necessary project management staffing for each domain.”

Asked whether the APG-81 has 24 DRs and the AAQ-37 17 DRs, the F-35 JPO said that the numbers of F-35 radar and DAS deficiency reports are not “publicly releasable” but that the 24 radar DRs and the 17 DAS DRs in the RFI comprise “the deliberate planning requirement to ensure the contractor is prepared to handle potential DRs in the future.”

The APG-81 and AAQ-37 are to work in tandem to help provide long-range detection, tracking, and destruction of air and ground targets.

Northrop Grumman is developing the AN/APG-85 radar to replace the APG-81 on the F-35.

Mitchell Institute for Aerospace Studies’ report in June said that the APG-85, which is to field in F-35 Lot 17 under the Block 4 upgrade, will have twice the capability of the APG-81 and “is a powerful cornerstone of the F-35’s sensor suite.”

“The difference from an operational perspective is comparable to switching from 1990s-era dial-up to 5G internet,” the report said.

The APG-85 “can suppress, defeat, and deny the enemy’s use of the broad electromagnetic spectrum,” the study said. “This also enables better targeting of surface or airborne radars at further ranges. Additionally, standoff threat suppression operations will be significantly more effective in the support of a strike package and improve the survivability of terminally guided weapons being employed against high-value surface-to-air missile sites.”