F-35A Lightning II completes first aerial gun test

The F-35A Lightning II has completed aerial testing of its internal Gun Airborne Unit (GAU)-22/A 25mm Gatling gun system with three airborne gunfire bursts during a California test flight on October 30. This was the first in a series of test flights to evaluate the functionality of in-flight operation of the internally mounted 25mm gun throughout its employment envelope.

Three bursts were fired, one of 30 rounds and two of 60 rounds each from the four-barrel, 25-millimeter Gatling gun.  In integrating the weapon into the stealthy F 35A airframe, the gun must be kept hidden behind closed doors to reduce its radar cross section until the trigger is pulled. 

F-35A test aircraft AF-2, a loads-instrumented jet, underwent an extensive structural modification at Edwards Air Force Base, Calif. to a fully production representative internal gun configuration. The first phase of test execution consisted of 13 ground gunfire events over the course of three months to verify the integration of the gun into the F-35A. Once verified, the team was cleared to begin this second phase of testing, with the goal of evaluating the gun’s performance and integration with the airframe during airborne gunfire in various flight conditions and aircraft configurations. 

The 25mm gun is embedded in the F-35A’s left wing and is designed to be integrated in a way to maintain the F-35’s very low observable criteria. It will provide pilots with the ability to engage air-to-ground and air-to-air targets. The first phase of F-35 gun testing started in June, when initial shots were fired from the ground at the Edwards Air Force Flight Test Center’s gun harmonizing range. 

The gun system will be further tested with a production F-35A next year for integration with the jet’s full mission systems capabilities. The test team will demonstrate the gun’s effectiveness in both air-to-air and air-to-ground employment when integrated with the next generation fighter’s sensor fusion software, which will provide targeting information to the pilot through the helmet mounted display. At the end of the program’s system development and demonstration phase in 2017, the F-35 will have an operational gun.