In Search of a Role?

Loyal Wingman (Boeing)
Loyal Wingman (Boeing) – Uninhabited aircraft outfitted with stand-off weapons could accompany low-RCS aircraft into contested airspace to engage IADS electromagnetic threats.

The US Subcommittee on Tactical Air and Land Forces has asked the USAF to assess the feasibility of the Next Generation Jammer for its aircraft.

The Subcommittee on Tactical Air and Land Forces is part of the US House Committee on Armed Services. The latter is a House of Representatives standing committee. The subcommittee oversees US armed forces’ programmes across all services, according to its website.

In late July, the subcommittee published its legislative provisions for the 2022 National Defence Authorisation Act (NDAA). NDAA legislation covers the annual budgets of the US DOD. It stipulates funding levels and expenditure policies. One of the subcommittee’s key proposals on electronic warfare is noteworthy.

The subcommittee has asked the US Air Force to assess the feasibility of installing Raytheon’s AN/ALQ-249 incarnation of the US Navy’s Next Generation Jammer (NGJ) onboard USAF tactical aircraft. Three subsystems comprise the NGJ: The AN/ALQ-249 is the mid-band jammer. This is thought to detect and engage radar and communications emissions on frequencies of two to six gigahertz/GHz. Low-band (100 megahertz to two gigahertz) and high-band (six to 18GHz) jammers are also being developed. All three should be in service from circa 2026. The only aircraft currently earmarked for the NGJ is the US Navy’s E/A-18G Growler electronic warfare jet.

Radar Cross Section

The subcommittee’s request could see the USAF evaluating the AN/ALQ-249 for deployment with Lockheed Martin F-35A Lightning-II and F-22A Raptor combat aircraft.

Both the F-22A and F-35A deploy their weapons from internal bays. This ensures that the low Radar Cross Section (RCS) of these aircraft stay free of protrusions potentially compromising this. Mounting the AN/ALQ-249 externally could increase both jets’ RCS.

Another option could be to install the AN/ALQ-249 in the aircraft’s weapons bay. This raises several challenges: The pods carrying the AN/ALQ-249 on the E/A-18G are mounted below the wings. This provides an uninhibited field-of-view to detect and jam hostile emitters. Both the F-22A and F-35A would need to lower the pods below the aircraft for the same effect. This could compromise their RCS and impinge on their aerodynamics.

As the Growler’s two pods are mounted beneath each wing this ensures one always has a line-of-sight to the threat when the aircraft is banking. Mounting two pods in these jets’ weapons bays could be problematic. The pods’ proximity could cause interference between jamming signals directed against simultaneous threats. An added problem with the pods’ internal carriage is that these aircraft will have no additional room for weapons.

Role?

Should outfitting the F-22A or F-35A be unfeasible, the air force has another option. It could consider installation onboard the Boeing/McDonnell Douglas F-15 or General Dynamics/Lockheed Martin F-16 series aircraft. Underwing hardpoints on these jets may make this more feasible.

However, this raises additional challenges. Steve ‘Tango’ Tourangeau, dean of the RV Jones Institute, a centre of excellence for electromagnetic spectrum operations, is concerned about how the AN/ALQ-249 would fit with the USAF’s overall anti-access/area-denial posture.

Investments by near-peer adversaries like the People’s Republic of China and Russia place a premium on advanced Integrated Air Defence Systems (IADS). These use sophisticated ground-based air surveillance radars to detect and track hostile aircraft. The IADS would play a key part in ensuring that China and Russia’s combat aircraft and surface-to-air missiles (SAMs) can exact as heavy price on an aggressor.

It is no surprise that the USAF prioritises RCS reduction for its combat aircraft. This helps ensure they are as difficult to detect and track as possible by fire control radars equipping SAM batteries and combat aircraft. Both the F-22A and F-35A are ‘first day of war’ weapons. They would assist the immediate roll back of an IADS to help sanitise the airspace for non-stealthy platforms.

Aircraft like the F-15 and F-16 would be at considerable risk flying in contested airspace. Eagles and Vipers equipped with the AN/ALQ-249 could remain at stand-off ranges performing electronic attack. With a service ceiling of 65,000 feet (20,000 metres), an F-15 equipped with the AN/ALQ-249 would have a jamming range of circa 313 nautical miles (580 kilometres). This translates into a jamming footprint of 407,589 square nautical miles (1 million square kilometres). While this might provide good coverage at the edges of areas protected by an IADS, it may not cover aircraft prosecuting targets deep in hostile territory.

Adding jammers to the F-15 or F-16 also risks these aircraft’s RCS: “These are not stealth platforms, and hanging jammers on them makes them less stealthy,” Mr. Tourangeau continues. He concedes that legacy fighters carrying the AN/ALQ-249 maybe practical for lightly contested airspace where a modicum of threat persists. This could include adversaries who lack strategic/operational SAM batteries but deploy operational/tactical level systems. This could also free the navy’s EA-18Gs from having to perform this type of mission during future operations.

Mr. Tourangeau believes that other options are more practical for the USAF in prosecuting the advanced electromagnetic threats accompanying an IADS. These include stand-off weapons like Lockheed Martin’s AGM-158 series Joint Air-to-Surface Stand-Off Missile and/or Raytheon’s AGM-88F HARM (High Speed Anti-Radiation Missile). These could be integrated onto uninhabited aircraft accompanying low RCS platforms in contested airspace.

by Dr. Thomas Withington

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Editor, Defence commentator, journalist, military historian.