B-1 bombers, B-1B, will soon have new eyes in the backs of their heads. Northrop Grumman and the USAF have signed a contract to update the aging AN/ALQ-161A defensive countermeasures system.

Objects in Mirror…

The BONE plays host to a suite of electronic countermeasures systems. When you’re flying in contested airspace with tons of high-explosives, a good rear-view mirror lets you see the tailgaters long before they’re “closer than they appear.” When those tailgaters have air-to-air missiles or their buddies on the ground have surface-to-air capabilities, it’s time to adjust the mirrors and prepare for some defensive driving.

Airmen from Dyess Air Force Base, Texas, remove an engine from a B-1B Lancer at Barksdale Air Force Base, Louisiana, July 7, 2021. (U.S. Air Force photo by Airman 1st Class Chase Sullivan)

The AN/ALQ-161A is the rear-view mirror for the B-1B Lancer. Purpose-built for the platform in the mid-’80s, the defensive suite has a 360-degree ability to identify, acquire, and jam enemy radars automatically, freeing the crew to fly and bomb. It also provides the rear-view mirror in the form of the Tail Warning function (TWF). “Twiff” is a souped-up mirror that can detect missiles coming from the rear.

A Little History

Touted as the first-ever fully-integrated electronic countermeasures, the AN/ALQ-161 was plagued with problems from the start. Developed by AIL Systems in the mid-70s, the ECM requirements were developed in response to Soviet threats known from the late 60s and early 70s, when the B-1A program was still on the table. Once President Carter ended the B-1A program in 1977, those requirements were put in stasis, to be rolled out when Reagan re-opened the new and improved B-1B program.

AIL dusted off the same system developed for the B-1A, slapped it in, and called it good. Over-simplification, true, but that was the gist. Once the Air Force realized 161 was never going to meet promised design parameters, it renegotiated the contract, spiced it up with “expired” funds to the tune of $1 billion, and made AIL modify the system to increase functionality. Not only would it cost more, but it would also still do less than promised.

Evolution is a Slow Process

AN/ALQ-161 has been overhauled a few times in its history. While the hardware has remained largely the same, software updates, known as “Block” updates, have allowed the system to morph and evolve into what crews need to counter emerging threats. Radar threats are not the same today as in 1970, and updates allow the system to keep up with new technologies. This latest update will (hopefully) bring the ECM suite in line with current and future threats.

On the ground, before a BONE takes off, defensive avionics technicians operate a PLM-4 test set, affectionately termed a “squirt-box,” that interrogates the components of the system. These checks are performed while the crew is on the aircraft, and the DAS technician and defensive systems operator onboard communicate to test system functionality before the flight. An insider with operational knowledge of the system says, “You could reprogram them (the radar signal simulator) to match what band needed testing” and test individual capabilities.

Ground crews move a B-1B Lancer into position at the Benefield Anechoic Facility
Ground crews move a B-1B Lancer into position at the Benefield Anechoic Facility on Edwards Air Force Base, California, May 20, 2021. (Air Force photo by 1st Lt. Christine Saunders)

Updates to the system come after some unique testing. In 2018, the Benefield Anechoic Facility (BAF) at Edwards AFB, CA, hosted a B-1B to provide comprehensive scenarios to its ECM suite. The BAF is the world’s largest anechoic facility. Anechoic literally means “free from echo.” The BAF lets technicians introduce simulated threats to the B-1 without interference from reflected signals or nearby radio interference. The BAF gave maintainers the ability to simulate the aircraft identifying and responding to threats while airborne.