WASHINGTON — The airplane that will one day be the Air Force’s next electronic warfare aircraft, the EC-37B Compass Call, has made its first flight and the contractor handling the program says it is on track to be delivered to the service for testing next year.
The current version of the Compass Call, the EC-130H, played a lesser-known — but vital — role in the last two decades of war in the Middle East region, jamming the communications and bomb transmissions of militant groups such as the Taliban and Islamic State. But those decades-old air frames — some of which date back to the Vietnam War era — are aging and sorely need replacing.
The Air Force in 2017 awarded a contract to L3Harris Technologies to carry out the Compass Call’s crossdeck program, which transplants the electronic warfare equipment from the legacy EC-130Hs into new Gulfstream G550 business jets. BAE Systems handles the electronic warfare components of the Compass Call.
L3Harris has carried out roughly a dozen test flights of its first Compass Call at the Gulfstream facility in Savannah, Georgia, Luke Savoie, president of the company’s aviation services sector, said in a Monday interview. The initial flight of the new Compass Call took place Aug. 25.
These flight tests — including high-altitude flights at around 40,000 feet and other tests to make sure it can operate in low temperatures — are meant to certify the structural changes L3Harris made to the aircraft to accommodate the massive amounts of electronic equipment it will carry, Savoie said.
“It’s about waking the aircraft up after its modification, before it gets into its next phase,” Savoie said.
The Air Force currently flies G550s under the designation C-37B to transport high-ranking government or Defense Department officials around the world.
But instead of luxury cabins and plush seating for VIPs, the EC-37B will be packed with a broad array of electronics meant to sow confusion in enemy ranks.
In a 2017 interview with Air Force Times, the former commander of the 43rd Expeditionary Electronic Combat Squadron said the Compass Call’s job in the war against ISIS was to jam their communications and radar on a daily basis.
“The bottom line is, if you can’t talk, you can’t fight,” then-Lt. Col. Josh Koslov, who is now a colonel, said at the time. “Our job is to create massive confusion in the [ISIS] network.”
Savoie said the EC-37B, when complete, will be able to fly much higher and faster than the older Compass Calls. The Air Force said the EC-130H has a ceiling of 25,000 feet and can hit 300 miles per hour. But Savoie said G550s can typically fly into the mid-40,000 foot range and nearly twice that speed, expanding the range of what its EW systems can target.
“Twice the altitude is twice the horizon, that you can see the world that you can affect and interact with,” Savoie said. “It’s all about altitude and speed.”
But because the EC-37B is based on the commercially available G550, and not a military-specific airframe, Savoie said it is expected to be easier for the Air Force to maintain. The new Compass Call will be able to be maintained primarily in the field, he said, without the need for significant depot maintenance time like the decades-old EC-130Hs require. This, he added, will mean less aircraft downtime.
Flying the older EC-130Hs in the harsh and dusty Middle East environment for decades proved taxing. Maintainers needed to regularly inspect the airframes for structural weaknesses and watch out for problems with its wiring and engines. Maintaining the new electronic warfare equipment that had been added to the old planes — one of which first flew in 1964 — also was a significant challenge.
The modification to the G550s to make them into Compass Calls will take place in two phases, Savoie said. The first phase, conducted in Savannah, involves modifying the exterior, including expanding the aircraft’s side panels, nose, and tail and installing radomes, external arrays and antennas. L3Harris is also installing the bulk of the wiring harnesses, liquid cooling systems and power distribution systems in that phase.
During the design process, Savoie said, L3Harris used as a blueprint the way G550s were previously modified into the Conformal Airborne Early Warning, or CAEW, aircraft flown by Israel and Singapore’s air forces. Following the CAEW design, instead of creating a new design, simplified the process and reduced risk, he said.
The flight tests went smoothly, he said, with no flutter problems or other issues that can arise when modifying aircraft with unique shapes.
But when an aircraft is modified, factors such as the center of gravity also change, he said. So L3Harris had to ensure autopilot functions and avionics, among other items, were responding to how the aircraft is currently shaped and operating correctly.
“Obviously, whenever you make significant outer mold line changes to an aircraft, [there are] tweaks to the avionics, especially advanced systems like Gulfstream employs,” Savoie said. “That’s what our flight test has proven out, that those changes have been effective.”
In the second phase, which will take place at the L3Harris facility in Waco, Texas, the company will install mission-specific hardware, such as crew consoles and stations. L3Harris already conducts depot maintenance for EC-130s in its Waco facility.
The electronic warfare equipment that will be installed in the new Compass Calls will partly be drawn from the legacy aircraft, and partly new equipment, Savoie said. Some parts in the older aircraft needed more miniaturization; in other cases, components were obsolete or outdated.
“We are incorporating the DNA of the EC-130H — not just the DNA, we’re doing organ transplants,” Savoie said.
Over the EC-130H’s two decades in the Middle East, Savoie said, the Air Force learned it needed to be agile and quickly adjust to handle emerging threats or counter new capabilities.
The EC-37B is intended to be similarly agile, by making it easy to add new capabilities — likely with software updates — when the need arises, he said.
Savoie said L3Harris’ first Compass Call, known as aircraft one, is expected to finish the first phase modifications this month. At the same time, the company has started laying the groundwork for the second phase by conducting preassemblies and creating a mockup aircraft. The first aircraft is expected to arrive in Waco at the end of October.
L3Harris is working on modifying six aircraft into EC-37Bs, Savoie said, and the Air Force eventually hopes to have 10 in its fleet.
L3Harris will finish modifying the first EC-37B in 2022 and deliver it to the Air Force for its own developmental test cycle by the end of next year, he said. He declined to say when the following EC-37Bs might be delivered.
Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.