Re-engining the E-8 JSTARS

The Engines

Military studies indicate that structural improvements and other modifications could allow the aircraft to fly safely for another 40-50 years. Significant performance improvements are being considered, but the fleet’s #1 issue remains its old JT3D-3B engines, whose core design was first introduced in the 1950s. An upgrade program is underway to address that, and the US Air Force finally appears to be on board. Mostly.

The choice facing the US Air Force involved 2 candidates:

One was GE’s very popular CFM56 high bypass tubofan, which flies on a wide variety of commercial jets including the entire Airbus 320 family, the A340, and Boeing’s 737-300+) and has been used to re-engine the USA’s 707-derived KC-135 Stratotanker fleet. The new KC-135Rs have demonstrated about a 27% fuel savings since the switch, in addition to lower maintenance costs, compatibility with the KC-135 fleet, and the ability to leverage a wider commercial skills base.

The other option would be Pratt & Whitney’s JT8D-219, based on an engine design that was introduced in the mid-1960s. It powers DC-9, MD-80, Boeing 727, and early-model 737 aircraft. While the fuel savings would be slightly smaller, the JT8 has an advantage of its own: no significant aircraft modifications are required, because the engine has the same weight and center of gravity as the older JT3D engines in current use.

This seemingly minor feature means significant capital and time savings for the re-engining program, and ended up determining the USAF’s choice. The JSTARS fleet is always in demand, and high project costs elsewhere mean a cash crunch for investment, so the Pratt & Whitney offering won.

The JSTARS engine upgrade program is based on the Propulsion Pod System, incorporating Pratt & Whitney’s JT8D-219 jet engine and Seven Q Seven’s pylons, thrust reversers, and instrumentation. Benefits are expected to include 17% fuel savings, added power generation for future upgrades to the radar sensor and mission equipment, elimination of engine overheating in warm months that sometimes forced the planes to fly at night, and the ability to use shorter runways. That last capability may allow the E-8Cs to fly from runways closer to some of their operating areas, which reduces the need for aerial tankers and adds fuel savings of its own.

Northrop Grumman added an innovation of its own, via a single stage precooling design that allows hot, compressed bleed air from the engine turbines to be processed at much cooler temperatures and more consistent pressure levels. That vastly improves reliability and the hardware’s life cycle, even as it keeps a number of critical systems functioning. The bleed air is used to pressurize the Air Cycle Machines (ACM) that cool the interior, cabin and prime mission equipment (PME); and also pressurizes the utility hydraulic subsystem, engine starting capability, and liquid cooling system.

Program: Current State

Northrop Grumman representatives said that civil certification was completed in October 2008, as noted below. The T-3 testbed plane has been flying, and flight tests for military certification remain on track. That testing has continued into 2011.

Funding for the re-engining program has been appropriated by Congress, and on Sept 30/09 Pentagon technology chief Ashton Carter directed the US Air Force to free up funds for initial production, but the full go-ahead hasn’t happened yet.

The funding is being used to buy JT8D-219 engines and Seven Q Seven’s propulsion pod systems as long-lead material items, which take time to produce. At this point, 2 initial pod sets are under contract, but a Milestone C decision to produce the remaining engines and pods isn’t scheduled until 2012.

Once military certification is complete, and a decision is made to produce the engine pods, having the equipment on hand would mean that re-engining could begin during the 17-plane E-8C fleet’s routine depot maintenance (PDM) cycles. Each E-8C enters PDM every 18 months, and the inspection and maintenance process last for about 4-6 weeks per plane. The entire E-8C fleet could be re-engined in about 2 years this way, while remaining available for use at their normal rates.

Beyond the re-engining program, the E-10’s demise may yet see the work on that plane’s full size MP-RTIP radar transferred to the E-8 fleet. Smaller MP-RTIP radars currently fly on RQ-4B Global Hawk UAVs, but a move to install the full version on the E-8 fleet would improve their ability to find ground targets by a factor of 5x – 10x. “Jumped-up JSTARS: New Technology for Ground Surveillance Planes?” covers those developments.

As the USAF thinks about investing in its E-8C fleet, both re-engining and wider upgrade plans may find themselves in trouble. There’s a serious debate concerning the wisdom of keeping the current JSTARS fleet at all, given its operating costs and age. Boeing is pushing a modified variant of its 737-derived P-8A Poseidon sea control aircraft, whose surface-looking radars are reportedly already competitive with JSTARS, as a similar-cost solution versus E-8 re-engining and upgrades. Radar capabilities could be improved further using existing technology, while keeping the P-8’s new electronics, new airframe, and operating efficiencies.

Contracts & Events

September 30/19: Modernization And Sustainment Northrop Grumman Systems won a $495 million contract for the E-8C Joint Surveillance Target Attack Radar System (JSTARS) aircraft. This contract provides for modernization and sustainment of 16 mission and one trainer aircraft. The deal will support the current JSTARS Program Office and Air Combat Command projections of improvements to increase or maintain E-8C performance, capability, reliability, and maintainability. The JSTARS is an airborne battle management, command and control, intelligence, surveillance and reconnaissance platform. Its primary mission is to provide theater ground and air commanders with situational awareness to support military operations. In 2015, team JSTARS set a major milestone when they surpassed 100,000-combat flying hours in support of the US Central Command while flying the E-8C Joint STARS out of Al Udeid Air Base, Qatar. Northrop will perform work at Robins Air Force Base, Georgia; and Melbourne, Florida, and is expected to be completed by Sept. 26, 2024.

Dec 14/11: Northrop Grumman announces that its JSTARS T-3 testbed aircraft has successfully completed its first official flight using the new, Pratt and Whitney engines, and the newly designed pneumatic system for bleed air cooling.

Feb 9/11: Northrop Grumman Corporation announces completion of the Preliminary Design Review for the JT8D propulsion pod’s new bleed air system. That system extracts high-pressured hot air from the JT8D’s engines and converts it into cool air that can pressurize the Air Cycle Machines (ACM) that cool the interior, cabin and prime mission equipment (PME), while pressurizing the utility hydraulic subsystem, engine starting capability and liquid cooling system. The new bleed air system is only expected to be installed and flight tested around mid-2012.

Jan 14/11: 20th anniversary of the E-8 JSTARS’ 1st operational combat sortie in 1991, which happened in support of Operation Desert Storm. Since 2001, the 116th Air Control Wing based on Warner Robins, GA have flown over 63,000 hours in 5,200 combat missions in support of Operation Iraqi Freedom, Operation Enduring Freedom and Operation New Dawn. Source.

Sept 13/10: End of JSTARS? The battle over the E-8 JSTARS fleet’s future is heating up. Boeing is proposing a derivative of its P-8A Poseidon sea control aircraft as a proposed $5.5 billion, 1-for-1 replacement of the current E-8C fleet, instead of paying that estimated amount to upgrade the E-8Cs with new cockpits, sensors, and engines. The Boeing AGS version would include the Raytheon-Boeing Littoral Surveillance Radar System (LSRS), Raytheon’s AN/APY-10 multi-mode radar in the nose, some the same Electronic Support Measures for emissions geo-location that are featured on the E/A-18G Growler electronic attack plane, and an electro-optical surveillance and targeting turret. A P-8 derivative would also give the USAF space and integration for weapons on board, or additional sensors in those spaces.

Northrop Grumman believes the Boeing figure may be a lowball price, and has its own proposal to add 1′ x 8′ array radars on the plane’s cheeks, derived from the firm’s APG-77 and APG-81 AESA radars that equip the F-22 and F-35 stealth fighters. Today, JSTARS operations have to “break track” with a target to collect an image. The cheek fairings would solve that problem, while keeping the existing AN/APY-7, in order to lower the upgrade price to around $2.7 billion: $900M re-engining, $500M for new APY-7 receiver and exciters, $1 billion for the cheek array, $300M for avionics upgrade and battle management improvements. This would replace the previous push to replace the APY-7 with their MP-RTIP radar.

Northrop Grumman executives have expressed concern that USAF officials haven’t showed them the 2009 initial capabilities document that could launch a competition to replace or upgrade the E-8C. That isn’t a required step, but it is common practice. This may be because the USAF is considering even wider options – like putting the focus on “persistent ground looking radar and optical surveillance with high resolution moving target capability,” instead of an E-8C vs. 737 AGS competition. If so, the firms could find themselves competing with other platforms, possibly including derivatives of airship projects like Northrop Grumman’s US Army’s LEMV etc. Aviation Week | Flight International.

Feb 25/10: The expanded Phase II effort is awarded to Northrop Grumman Corp., with $60 million added to the contract, bringing it to $283.6 million. This Phase II contract includes flight testing, data capture for flight simulators, modified air certification, pneumatic system development, training, logistics, flight manuals and logistics design efforts. Maj. Kevin Massie, commander of the 633rd Electronic Systems Squadron, offers his take on past delays in a March 18/09 USAF article:

“Concerns about long-term fleet viability and program cost growth led to a delay in execution and outright halt of portions of the program in August [2009]. In late September, after being presented with several options, the Air Force directed the continuation of the Re-engining System Design and Development phase, with the intention of moving toward a Milestone C decision for production of the remaining E-8C engine shipsets in fiscal 2012.”

The article adds that this decision was reinforced by a pointed ADM released on Sept 30/09 – see below.

Feb 9/10: The 751st Electronic Support Group at Hanscom Air Force Base, MA finalizes a $223.6 million contract with Northrop Grumman to supply 2 JSTARS propulsion pod system (PPS) shipsets to the Georgia Air National Guard. The PPS shipsets each consist of 4 Pratt and Whitney JT8D-219 engines, pylon assemblies and associated aircraft interconnections.

Deliveries are expected to begin in 2011 pending final military certification of the engines on T-3, the JSTARS 707-300 test bed aircraft. See NGC release. A Northrop Grumman representative provided DID with the following explanation of the contract funding:

“The $223.6M contract we signed had predominantly FY08 and FY09 appropriated funds that we finally received in 2010 [as a result of] the [Ashton] Carter directive…However, of the $223.6M awarded, we estimate about $9.5M appears to be from FY10 RDT&E and $500K is FY10 procurement. That’s about $10M of FY10 funds paying an FY08/ FY09 bill.”

Oct 19/09: Commenting on Pentagon technology chief Ashton Carter’s decision to direct the Air Force to free up funds for the new JSTAR engine sets, Lexington Institute’s Loren Thomson says that:

“If the Air Force had obligated money in a timely fashion, the first two sets of engines would be funded, but instead it is asking Congress to make up a shortfall its foot-dragging created, which amounts to seeking money for the same item twice. This mess doesn’t build confidence about the Air Force’s commitment to supporting the needs of soldiers, soldiers being the main consumers of JSTAR reconnaissance. But it’s more important to get warfighters what they need than to have an inside-the-beltway wrangle over who’s to blame… Carter needs to hold Air Force feet to the fire… and Congress needs to provide the money… There are only 17 planes in the JSTARS fleet, but it looks like we’re going to have to rely on them for a long time to come, and as of right now not one has the new engines needed to stay viable.”

Sept 30/09: Pentagon technology chief Ashton Carter signs a memorandum, [PDF] which was introduced into the Congressional Record, directing the Air Force to free up funds for the JSTARS PPS shipsets to begin initial production. The memo reads:

“I direct the Air Force to continue the JSTARS re-engining System Design and Development phase, including the development, flight testing, and production of the initial increment of re-engine shipsets. The Air Force should immediately identify and obligate RDT&E and procurement funding necessary to executive this direction.”

July 29/09: The Lexington Institute publishes “Air Force Delay on Radar Plane Fix Hurts Soldiers.” An excerpt:

“Now, it can’t even find money to replace the plane’s failing engines. The latter problem is a remarkable example of bureaucratic foot-dragging, when you consider that defense authorizing and appropriations committees in both chambers of Congress have already approved the money… As a result, about once every ten days the Joint Stars fleet has to abort a mission due to malfunctioning engines, and half the time an in-flight emergency is declared. Needless to say, this tends to reduce the readiness of the plane while greatly increasing maintenance bills.

The Air Force’s own estimates show that if it replaced the E-8’s decrepit engines with new ones, it could avoid about a million dollars a day in maintenance costs. In fact, the replacement program would pay for itself in eight years, and eventually save $10 billion… without new engines, it will probably become unflyable in the next decade.”

Dec 20/08: A USAF E-8C test bed aircraft makes its first flight powered by the new engines. This flight marks the start of the re-engined E-8C’s military air worthiness certification test program, which will last “into next spring.” Northrop Grumman release.

Oct 22/08: Northrop Grumman announces that the USAF’s E-8C engine upgrade program had successfully completed Federal Aviation Administration supplemental type civil certification flights.

After civil certification was complete, the engines and pylons were removed from Omega Air’s 707, for installation on a military E-8C aircraft that would be used for military certification.

May 13/08: Northrop Grumman announces 2 unfinalized USAF contracts worth $300 million. Their team will complete non-recurring engineering, flight test, and certification of new PW JT8D-219 engines for the service’s E-8C JSTARS fleet, and begin engine production. Work will begin immediately, with the test bed aircraft in Melbourne, FL being the first E-8 to convert to the Pratt and Whitney JT8D engine and begin military flight certification later this year. Concurrently, production startup activity begins with Northrop Grumman’s principal subcontractors to produce the propulsion pod system.

The first retrofit to the Joint STARS fleet is set for late 2010. All refits will take place during routine periodic depot maintenance schedules, in order to ensure the least amount of down time for the in-demand JSTARS fleet. NGC release.

Jan 18/07: Northrop Grumman selects Pratt & Whitney’s JT8D-219 engine to power the E-8 JSTARS conversion project. The effort will be a joint venture involving United Technologies’ subsidiary Pratt & Whitney and Seven Q Seven (SQS), will produce and deliver the complete JT8D-219 propulsion system. Pratt & Whitney will be responsible for delivering the engines, and SQS will work with its key suppliers Goodrich Corporation and The Nordam Group to supply the propulsion pods the engines rest in, including the struts, cowl doors, inlets, reversers and systems. Pratt & Whitney release.

Additional Readings

• USAF Fact Sheets – E-8C Joint Stars

• Northrop Grumman – E-8C Joint Stars. Northrop Grumman is the E-8C’s lead integrator; the base plane is Boeing’s.

• Pratt & Whitney – JT8D

• DID – Jumped-up JSTARS: New Technology for Ground Surveillance Planes?

• Lexington Institute (July 29/09) – Air Force Delay on Radar Plane Fix Hurts Soldiers

• USAF (Dec 4/08) – E-8C’s new engine program takes off

• DID (Nov 23/05) – USA Spending $532M to Upgrade its E-8 J-STARS Eyes in the Sky