Boeing (St. Louis, MO) has chosen BAE Systems (Nashua, NH) to develop and manufacture the Eagle Passive Active Warning Survivability System (EPAWSS) for the US Air Force's F-15C and F-15E fighter aircraft. With the F-15 now scheduled to remain in service through 2040, the next-generation, all-digital, EW system is part of a multi-billion dollar program to develop a complete, integrated aircraft protection system for the aircraft as well as provide it with improved situational awareness.
EPAWSS will replace the F-15's current Tactical Electronic Warfare Suite (TEWS) on F-15C and F-15E model aircraft. Originally developed in the 1970s
and upgraded several times since then, TEWS is a federated EW system incorporating BAE Systems' (Nashua, NH) AN/ ALR-56C Radar Warning Receiver (RWR), Northrop Grumman's (Rolling Meadows, IL) AN/ALQ-135(V) radar jammer, and BAE Systems' AN/ALE-45 chaff/flares countermeasures dispenser. Intended to address both advanced RF and electro-optic/infrared (EO/IR) threats, the EPAWSS will be a multispectral system that provides wideband radar warning and RF jamming, as well as increased chaff and flare protection. As described by Brian Walters, Vice President and General Manager of Electronic Combat Solutions at BAE Systems, "To be able to operate in the future threat environment, the F-15 is going to need a new, highly-capable EW system.
EPAWSS really leverages a lot of the work we've done over the last 15-20 years providing EW suites to the F-22, F-35 and, recently, we were selected to provide a digital EW system, the DEWS system, for Boeing's Advanced F-15 program. As, an all-digital system, [EPAWSS] leverages some very agile architectures and allows us to adapt to changing threats. Its processing capability, together with the way we go about processing signals, means it's able to handle an incredible level of threat density and be extremely flexible in terms of dealing with modern Integrated Air Defense Systems (IADS).''
The US Air Force awarded Boeing, as the platform integrator, a $171 million contract for the Technology Maturation and Risk Reduction (TMRR) phase of EPAWSS. Boeing subsequently chose BAE Systems to develop and produce the system. As described by Evelyn Moore, Boeing F-15 EPAWSS Program Manager, "Although the total program is valued at over $4 billion, the Air Force doesn't necessarily have $4 billion in funding for EPAWSS right now, so the program is broken up into individual phases. We've received a contract for the design phase, and BAE is leveraging the DEWS system and pieces from EW systems on other programs that all come together in this TMRR design phase for EPAWSS at Boeing."
The Air Force and Boeing began work on EPAWSS with a small characterization contract in which they conducted trade studies on potential system performance,
installation and locations, removal of the old system, the volumes in which the new system would be installed, and other considerations. A source selection for
the EPAWSS supplier was begun in 2014. Says Moore, "We did multiple studies. We started off with four bidders and we ran through a vigorous competition process at Boeing with oversight from the Air Force and the Defense Contract Management Agency (DCMA)."
Although Boeing would not comment on the other competitors, it has been previously reported that Harris (Clifton, NJ), Northrop Grumman (Rolling Meadows, IL) and Raytheon (El Segundo, CA) had expressed interest in the program. Mike Gibbons, Boeing Vice President F-15 Programs, says "it was an iterative downselect
process, and definitely a very competitive environment. Beyond the four bidders, there were also a number of other companies that were in discussions early on to learn if their offerings might be competitive. EPAWSS is a major component of the F-15's future out beyond 2040, and BAE's system is a game-changer,
building a lot on what BAE has been doing with other EW systems both for the F-15 and other platforms."
BAE's Walters recalls the process as "a very efficient and disciplined pursuit," noting that "one thing that Boeing and the Air Force did that I think is a best practice, is that they wove in a Systems Requirements Review (SRR) as part of each competitors offering. This gave everyone an opportunity to say 'Do we all
understand the requirements, and do we all understand how we will meet the requirements?' When I first heard of this, I kind of scratched my head, but in the
end, it allowed all of us to bring forth the best solution for the F-15 and will serve the program well going forward."
One of the questions surrounding the design of EPAWSS has been the choice of technology that would be used to power the system's jammer transmitters, whether a solid-state amplifier approach or more conventional traveling wave tube (TWT) technology. Walters answers that question saying BAE's approach is a GaN-based solid-state amplifier design. "We already consider it to be in the TRL-7 to TRL-9 range, and it will definitively be TRL-9 very shortly. We're already deploying this technology on other programs."
In addition to improved aircraft protection, EPAWSS will also provide pilots with improved situational awareness. Says Walters, "This is possible because of the advancements that we've made in algorithm processing, as well as hardware performance. It's enabled us to do a lot of things on the electronic support measures (ESM) side or RWR side that provide precision location, reduce ambiguity, improve emitter ID, and better understand the intent of the different emitters. This all leads to providing the pilot with better situational awareness of the environment that he is operating in.
" EPAWSS will also improve the F-15's chaff and flare capabilities, including design work on the aircraft's tail to enable it to carry more "buckets" of both chaff and flare expendables. Moore points out that there are extensive aircraft modifications required to put a new EW system on an aircraft including, in this case, removal of the wings and replacement of the aircraft's 'tailbone' between the engine exhaust nozzles. "A lot of work has to be done all over the aircraft to support the program. We're taking off all of the TEWS components,with a savings of 13 LRUs [Line Replaceable Units] going from TEWS to EPAWSS, so a lot of weight is being removed from the aircraft, as well as providing for a smaller footprint." Moore adds that the determination of the composition of the Group A (cables, panels, etc.) and Group B (actual EPAWSS components) modification kits, including any"swing" elements was also a challenge. Boeing makes these determinations together with the Air Force. "It's always the case with a system of this complexity," says Moore. "However, we're leveraging a lot of the work that we've already performed on the Advanced F-15 and, although that is a new aircraft build and this is a retrofit, we're able to leverage some of the design that we've already done on the platform, which is helpful."
Boeing anticipates receiving a follow-on EPAWSS contract from the Air Force in September 2016 for the EMD, integration and test phase of the program. This will be followed by a low rate initial production (LRIP) phase currently anticipated for August 2019. As Moore notes, "EPAWSS is an Acquisition Category 1 program (a program over $2 billion), so we go through an extensive acquisition process and must pass through each of the Air Force's milestone gates to proceed into the next phase." In the LRIP phase, 24 F-15E model aircraft and 18 F-15C model aircraft will be modified. The remaining aircraft will be upgraded in the full-rate production phase with, ultimately, over 400 F-15E and F-15C model aircraft to be equipped with the new system. Initial Operational Capability (IOC) is targeted for 2021 for E-model aircraft, and late 2022 for C-models.
In the EPAWSS Analysis of Alternatives (AoA) phase completed last year, the Air Force and OSD made a number of recommendations for the program going
forward. Among these were a missile warning system and a fiber-optic towed decoy (FOTD), as well as advanced geolocation capabilities for the ESM system. In
order to expedite development and fielding of the most essential capabilities, however, the Air Force decided to pursue these capabilities under a follow-on "second increment" of the program. However, as explained by Moore, "Although we will have growth provisions in the system for advanced geolocation and an FOTD, the Air Force has since decided not to fund the second increment at this point. There are several threats that are of concern, but we have to balance funding against the requirements and the time frame, and the most important item is to get the capability out to the fleet as soon as possible.
So the delay with the FOTD was basically because we didn't want to hold up the entire program. We wanted to keep it moving forward." Should the Air Force decide to fund the second increment in the future, Moore says they'd anticipate a second contract to start developing the requirements, "but we wouldn't see that until FY2017." Going forward, Gibbons says they're always looking at how to link the EPAWSS EW upgrade with other ongoing activities for the F-15 in terms of life extension and other new capability upgrades. "This is, of course, always an Air Force decision, but as we look at their interest in flying the aircraft for decades through 2040 and beyond, it's obvious that there will be other upgrades and life extensions. The aircraft modifications alone mean that we will want to look for possible synergies with doing other things. With an IOC in 2021, and mods ongoing through 2029, it just makes sense that there will be other upgrades and life-extension components that will be added."