With the recent announcement that BAE Systems will be the integrator of the USAF’s EC-130H Compass Call II electronic warfare capability onto a Gulfstream business jet platform, there are many similarities with, and some important differences to the ADF’s Project AIR 555 MC-55 electronic warfare support aircraft program.

Dr Thomas Withington takes a close look at the subsystems and capabilities which will equip the venerable EC-130H’s replacement, while Andrew McLaughlin adds some context about the AIR 555 program. 

On July 9 BAE Systems announced it had commenced work on the ‘Cross Deck Initiative’ to transfer subsystems from the USAF’s Lockheed Martin EC-130H Compass Call electronic warfare (EW) aircraft onto new Gulfstream G550-based EC-37B platforms, an initiative which BAE is jointly pursuing with L3 Technologies.

According to an official announcement on BAE Systems’ website, the company “will re-host the EC-130H’s mission equipment onto a higher-performing aircraft.” The company says the performance improvements of the EC-37B versus the EC-130H will be seen in the new aircraft’s higher operating altitudes, longer range, and higher cruising speed.

As a means of comparison, open sources note that the EC-130H has a flight ceiling of 25,000ft, less than half that of the 51,000ft capability of the Gulfstream G550 business jet upon which the EC-37B is based. Similarly, the EC-130H has a range of 2,295nm compared to 6,750nm range of the G550. Similar discrepancies can be found in the cruising speed of the EC-130H which is 258kts compared to the G550’s 459 knots. While the EC-37B’s extensive aerodynamic modifications will likely see these capabilities slightly reduced, the performance advantages are still compelling.

The G550 airframe can be adapted to host subsystems which require dedicated antennae apertures. To support such missions the aircraft has been certified to be modified with with large fuselage ‘cheek’ and fore and aft fairings. The mission currently performed by the EC-130H makes it imperative that the smaller EC-37B has sufficient exterior space to house the aircraft’s external antennae, alongside available interior volume to comfortably accommodate the mission specialists tasked with performing the aircraft’s mission.

To this end, BAE Systems says the EC-37B airframe will be based upon the G550 Conformal Airborne Early Warning Aircraft (CAEW) which has been developed by Gulfstream’s Special Missions Aircraft department. This aircraft has been adapted for service with Israel, Singapore and Italy by Israel’s IAI, and is fitted with IAI’s EL/W-2085 L-band and S-band airborne early warning radar.

For the RAAF’s AIR 555 requirement which is being led by L3 Technologies, the MC-55 will likely employ a variant of the USAF’s Boeing RC-135V/W Rivet Joint SIGINT mission fit. It is unclear whether that airframe will be the CAEW configuration, or a less modified version with a prominent ‘canoe’ fairing antenna aperture.

Baselines

According to the USAF, the EC-130H “disrupts enemy command and control communications, and limits adversary coordination essential for enemy force management.” The aircraft’s mission follows the communications jamming dictum ‘if you can’t talk, you can’t fight’.

The EC-130H’s mission was originally envisaged to jam the vital radio communications upon which the smooth functioning of an integrated air defence system depends, but has since evolved to include the jamming of hostile tactical communications on the battlefield, ground-based air surveillance radars, insurgent communications and even Improvised Explosive Devices (IADS).

The aircraft’s array of subsystems explains how it performs this diverse array of roles. The EC-130H fleet is spread across the 41st and 43rd Electronic Combat Squadrons (both part of the 55th Electronic Combat Group located at Davis-Monthan airbase, Arizona).

Public sources state that the USAF has a total of 14 EC-130H aircraft incorporating EC-130H Block-30/35 Baseline-1/2 platforms. According to official US government documents this fleet breaks down into ten aircraft which are in the primary mission inventory, four of which are in the backup aircraft inventory, and a single platform which is used as a testbed.

The USAF does not provide a breakdown as to precisely how many of these aircraft are of which configuration, but its literature stipulates that the EC-130H Block-35 Baseline-1 possesses “additional capabilities to jam communication, (ground-based air surveillance radars) and navigation systems through higher effective radiated power, extended frequency range and insertion of digital signal processing versus earlier EC-130Hs. Baseline 1 aircraft have the flexibility to keep pace with adversary use of emerging technology.”

US Congressional Research Service documents published in 2016 state that the USAF is transitioning all of its aircraft to the EC-130H Block-35 Baseline-2 configuration (see below).

Over the years, the EC-130H has received a number of important enhancements. The EC-130H Baseline-1 configuration outfitted the aircraft with a number of specific subsystems to support its Electronic Attack (EA) mission. These included Raytheon’s AN/ALQ-175 high-band RF jammer, AN/ALQ-198 low-band RF jammer and AN/ALQ-173 ‘blink’ jammer: The latter is thought to be used to provide an EA capability against monopulse radars causing the radar’s line-of-sight to continually move between two positions preventing an accurate fix on a target.

The aircraft’s EA capabilities are enhanced with the Generic Comms Jammer which does not appear to have been given a specific US Department of Defense designation. This is used for the communications jamming portion of the aircraft’s mission.

For the gathering of electronic intelligence, this EC-130H configuration carries an Argo Systems AN/ALR-63 instantaneous frequency measurement receiver which is thought to have a detection range in the region of 500nm, and provides up to three degrees of direction-finding accuracy.

Later Capabilities

Details of the EC-130H Baseline-2 specification are more sketchy, although official US DOD documents articulate that such equipment includes the Digital Signal Analyser and Exciter (AXE), and the BAE Systems Special Purpose Emitter Array (SPEAR) which can jam multiple emitters simultaneously via the transmission of four steerable, independent jamming beams.

The SPEAR pod is a particularly interesting capability. Open sources note that the pod can cover Very High Frequency (VHF) and Ultra High Frequency (UHF) wavebands of 30MHz to 3GHz.

Also hosted on the aircraft is the Integrated Modern Communication Receiver and Phased Array Transmit/Receiver antennae and Tactical Radio Acquisition and Countermeasure Subsystem (TRACS-C) which is thought to have replaced the aircraft’s legacy AN/ALR-63 subsystem.

US-led combat operations in Afghanistan from 2001 and in Iraq from 2003 underscored the effectiveness of the SPEAR pod when used in conjunction with the BAE Systems AN/USQ-113(V)3 communications jamming system which equipped the (now retired) US Navy and Marine Corps’ EA-6B Prowler electronic warfare aircraft.

Evidence suggests that in both theatres the EC-130Hs would perform precision spot jamming against specific communications threats, while the EA-6B would perform barrage jamming across other adversary communications networks.

The EC-130H’s subsystems configure the aircraft to not only perform Electronic Attack (EA) against an adversary’s military communications, but also against civilian communications. Recent operations have shown this latter capability to be particularly important.

For example, ISIS has made widespread use of civilian cellular and radio communications for command and control during their operations in both countries. US-led combat operations against ISIS under the Operation Inherent Resolve banner have witnessed significant activity by USAF EC-130Hs to disrupt these communications, and since 2016 open-source reports have noted that these aircraft have been particularly active in the Iraqi and Syrian theatres.

The aircraft was also deployed to support US and NATO-led operations in Libya in 2011 as part of Operations Odyssey Dawn/Unified Protector to uphold sanctions and arms embargoes against the Libyan government, and to protect Libyan civilians against forces loyal to the country’s erstwhile dictator Colonel Muammar Gaddafi. During this conflict, the aircraft played an important role in jamming both Libyan armed forces military communications, and also public sector and civilian radio communications which it was feared were being used for military command and control, according to the author’s sources.

Furthermore, the aircraft is furnished with the Improvised Explosive Device (IED) defeat subsystem called NOVA, which plays an important part in helping to neutralise IEDs and is a useful by-product of the aircraft’s jamming mission. Radio-controlled detonation either using cell phones or RF (Radio Frequency) remote control has long been a favoured method by insurgents to detonate an IED, but the EC-130H’s EA capability allows the aircraft to jam such devices or to transmit RF to pre-detonate them before they become a threat to friendly forces.

While neither BAE Systems nor the USAF have divulged more details on the EC-130H equipment that will be ‘cross-decked’ onto the new EC-37B, it is widely thought that this process will comprise several, if not all, of the aircraft’s subsystems including the SPEAR pod, NOVA and TRACS-C subsystems. Moreover, sources have informed Mönch that all ten EC-130H subsystem ship sets will migrate from the former to an identical number of EC-37Bs in the coming years.

For the RAAF, it is unlikely the MC-55 will have an active EA/EW capability like that to be employed by the EC-37B. More probable is that the passive L3-developed systems developed for at least two RAAF AP-3C Orions in the late 1990s under the Project Peacemate program will be similarly ‘cross-decked’ to the higher performing MC-55 platforms, and where necessary upgraded and miniaturised to be hosted on the smaller airframe.

The main body of this article was originally published on the www.monch.com website on July 19, and ADBR is grateful to Dr Withington and publishers of the Mönch Publishing Group for allowing us to reproduce this article.