Big Iron: The Air Force's Open Architecture for Electronic Warfare

Part of the Open Architecture Field Guide. All information is derived from unclassified, publicly releasable (Distribution A) sources.

Big Iron is the Air Force's open architecture for airborne electronic warfare. It standardizes how EW mission software plugs into an aircraft so capability moves between platforms instead of being rebuilt for each one. As of AMS-GRA version 14.0 it was absorbed into AMS-GRA, though it still stands on its own for programs that do not need the full AMS-GRA mission-system infrastructure, such as attritable drones.

What it does

Electronic warfare has been the hardest part of an aircraft to open up. A jammer or a warning receiver built for one platform rarely transfers to another, because the RF front end, the processing chain, and the mission software are usually specific to that airframe. Replacing or upgrading an EW capability then means a custom integration effort each time.

Big Iron standardizes the software and integration side of that problem. It defines how an EW capability connects to the mission system, how it is tasked, and how it reports. It works alongside SOSA, which standardizes the EW hardware: the cards, slot profiles, and chassis. One covers the software, the other the hardware. Built to both, an EW capability can port across platforms at both layers.

Spectral Autonomy

Where it sits

Big Iron is owned by the Air Force Life Cycle Management Center's Warfare Directorate (AFLCMC/WA). As of AMS-GRA version 14.0 (April 2026), it was absorbed into AMS-GRA. AMS-GRA comes from the same directorate, which is why the two converged. Big Iron still describes fielded electronic-warfare programs, but it is no longer developed as a separate architecture.

For a program office or a vendor, the effect is straightforward. Electronic warfare is now covered inside the AMS-GRA mission-systems architecture, under the same architecture as the rest of the mission system, rather than under a second standard tracked and reconciled on the side.

Big Iron still has a place of its own. An attritable drone or a low size-weight-and-power electronic-warfare payload that does not need the full AMS-GRA mission-system infrastructure can be built to Big Iron directly, rather than carrying everything AMS-GRA brings. It is no longer iterated as a separate architecture, but it remains the lighter target for programs that do not need the whole suite.

Spectral Autonomy

How it connects

An electronic-warfare system built to Big Iron sits within a small set of adjoining open standards:

• SOSA defines the EW hardware it runs on: the cards, backplane slot profiles, and chassis.
• OMS and UCI carry the command, control, and sensor data. OMS is the mission-system abstraction layer; UCI is the message set that moves across it.
• AMS-GRA is the mission-systems architecture Big Iron is now part of, and the compliance target a modern EW capability is built against.

Where it appears

Big Iron–aligned EW systems have flown in the Air Force Research Laboratory's AERRES campaign on MIRAGE pods. In 2026, BAE Systems demonstrated Big Iron and SOSA alignment across platforms beyond crewed aircraft, including weapon pods, Collaborative Combat Aircraft, larger unmanned aircraft, rotary-wing platforms, ground vehicles, and surface vessels.