Building Blocks

Initial work on the SLM is covered by a US$73m (A$94m) contract the United States Navy awarded to Boeing in February. While details of the SLM upgrade haven’t beeen revealed, they reportedly include various structural doublers, new material components, and corrosion inhibitors applied across key structural areas of the aircraft.

“SLM modifications are focused on specific airframe locations required to strengthen the aircraft to meet new life goals,” Boeing F/A-18 and EA-18 program manager Dan Gillian told Australian Aviation.

According to Boeing SLM program director Mark Sears, “The initial focus of this program will extend the life of the fleet from 6,000 to 9,000 flight hours.

SLM will extend the life of the fleet to 9,000 hours.’

“But SLM will expand to include Block II to Block III conversion, systems grooming and reset, and O-level maintenance tasks designed to deliver a more maintainable aircraft with an extended life and more capability,” Sears said in late February. “Each of these jets will fly another 10 to 15 years, so making them next-generation aircraft is critical.”

Boeing has previously pitched the SLM process as an ideal time for the US Navy to begin the incorporation of other proposed Block III enhancements for the Super Hornet.

“The Navy plans to upgrade Super Hornets that come into SLM to Block III aircraft in addition to extending its life from 6,000 to 9,000 hours,” explained Gillian. “SLM will start incorporating Block III capabilities in the early 2020s.

“SLM is the perfect time to add in Block III, because the Navy can add in capabilities via new buys off the production line and SLM, exponentially increasing the amount of Super Hornets in the fleet with next generation capabilities to stay ahead of the future threat.”

According to Gillian, the Block III upgrade package includes:

»» Enhanced network capability with a system that adds a new Distributed Targeting Processor-Networked (DTP-N) computer, network throughput via a new Tactical Targeting Networking Technology (TTNT) system, the addition of SATCOM, and much greater sensor integration.

»» Longer range with low-drag shoulder-mounted conformal »» Enhanced situational awareness with a new Advanced Cockpit System featuring new 10 x 19in large screen cockpit displays.

»» Reduced radar signature with low observable shaping and coatings.

»» The addition of already funded Super Hornet ‘Flight Plan’ elements such as the Lockheed Martin Long Range ASG-34 ‘IRST21’ Block II infrared search and track sensor, which is mounted in the front end of a centreline external auxiliary fuel tank, and upgrades to the APG-79 AESA radar.

‘The potential number of aircraft to be upgraded is huge.’

The IRST was the first adopted element of Block III, when a US$89m (A$113m) contract was awarded to Boeing last May for the integration of the sensor to the Super Hornet. Other elements planned include the integration of the ALQ-214 Integrated Defensive Electronic Countermeasures (IDECM) Block IV EW suite (IB-4) which replaces the Super Hornet’s ALQ-214(V)3 jammer with the new (V)4, and optical fibre wiring to support new sensors and weapons.

The TTNT and DTP-N are said to be where some of the real advances will come for the Super Hornet, providing sensor fusion and secure comms with other systems on a par with fifth-generation aircraft like the F-35. And with TTNT and DTP-N already funded by the US Navy for the EA-18G Growler, development and integration risk for these systems onto the Super Hornet should be low. “DTP-N is a big computer that is more powerful than current offerings,” explained Gillian.

“And TTNT is a big network pipe. With a big computer and a big pipe, you can do fusion on your aircraft and pass information back and forth across various platforms. The DTP-N lets you crunch all that data, and the TTNT lets you share it.”

The first SLM Super Hornet is expected to be inducted into Boeing’s St Louis factory in April, while newbuild aircraft incorporating the SLM enhancements and the first Block III upgrade elements will begin rolling off the line by the end of the year. The proposed FY19 budget provides a requirement for 110 new-build Super Hornets out to FY23 as part of its Future Years Defense Plan, all of which will be in the Block III configuration.

At this stage, no decision has been taken by the US Navy on whether it will upgrade its original Block I Super Hornets of which there are about 136 aircraft, many of which have been assigned to secondary training and air-to-air refuelling duties. The Block I has a different forward fuselage structure, and is fitted with the older mechanically-scanned APG-73 radar.

But even then, the potential number of aircraft to be upgraded is huge. The US Navy ‘program of record’ (officially stated requirement) is 769 F/A-18E/F and EA-18G jets, comprising 136 Block I Super Hornets, 160 Growlers and 437 Block II Super Hornets, in addition to the 24 Super Hornets and 12 Growlers delivered to Australia. On top of that there are 24 additional jets in the US FY18 budget which is still yet to be passed, and 110 in FY19.

The main key visual difference of the Block III Super Hornet will be upper fuselage-mounted conformal fuel tanks. In late February the US Navy awarded Boeing a US$219.6m (A$279m) contract to develop the CFTs for the Super Hornet airframe, covering the “design, development, test and integration” of the tanks.

Boeing first proposed the shouldermounted conformal fuel tanks for the Super Hornet as one of a number of upgrades for the jet as part of what it would later call the Advanced Super Hornet at the 2010 Farnborough Airshow. They are designed to increase the combat effectiveness of the Super Hornet and Growler through the addition of auxiliary fuel without the usual penalties of drag and the loss of wing and fuselage weapons stations that come from conventional external tanks.

In 2013, Boeing flew a Super Hornet demonstrator fitted with aerodynamic mock ups of the tanks, along with other proposed Advanced Super Hornet improvements, some of which have been adopted for the Block III.

That testing validated the aerodynamic performance of the design and showed that CFTs would increase the Super Hornet’s combat radius by up to 130nm, for a total combat radius of more than 700nm. The US Navy added conformal fuel tanks to its EA-18G Growler ‘Flight Plan’ in 2015, but until now they had not been funded.

The CFTs have a combined fuel capacity of 1,600kg (3,500lb) – slightly less than a Super Hornet’s 480gal/1,817L external tank. But the CFTs do not increase the aircraft’s subsonic drag, and increase transonic drag only equivalent to carrying a centreline tank. With some internal fuel system plumbing changes the CFTs were designed to be retrofittable to existing aircraft.

“It is obviously a change to the outer mould-line of the aircraft and we have to add some new plumbing under the skin,” said Gillian.

“While the war fighting benefit is huge, it’s a fairly straightforward change from an engineering perspective.”

The RAAF is likely to be very interested in the CFTs and other elements of the Block III upgrade, especially as, when acquired, Australia undertook to stay in “lock-step” with the US Navy’s Super Hornet and Growler upgrade ‘Flight Plans’.

Now that the Super Hornet is no longer considered a short-term bridging capability for the RAAF and will instead likely serve a nearly full life-of-type, many or all of these Block III elements will come into play if Australia stays on the US Navy’s upgrade path.

For Growler, the US Navy’s Block II program is still being defined, but some elements of the Super Hornet Block III program will be shared.

“Given that the Block II Growler is a Navy-led activity, questions (are better directed to) the US Navy,” Gillian said. “I can say that the Block II Growler will build on the existing Growler Flight Plan with Block III Super Hornet features like CFTs and the Advanced Cockpit System.”

Australia certainly sees much potential for enhancing the Growler over the longer term, with the 2016 Defence Integrated Investment Program roadmap of Defence capability spending providing some $5-6 billion in funding for upgrades to the electronic attack system.

For now Boeing is playing it safe on any questions about any RAAF interest in Block III.

“Right now, our focus is on developing capabilities that support a Block III delivery to the US Navy by the end of 2020,” said Gillian. “Australia is a valued partner and we have kept the RAAF up to speed on the Block III capabilities. Should the RAAF elect to upgrade their SH fleet, we will be happy to support it.”

‘The war fighting benefit is huge.’ DAN GILLIAN