Re-BUFFED

Key.Aero details what it will take to keep the USAF’s veteran bomber, the B-52H Stratofortress, operational and technologically relevant until its projected retirement around 2050.

Boeing’s venerable B-52 Stratofortress is the product of the USAF’s search for a long-range strategic bomber which began after the end of World War Two. By 1952, the air arm had accepted its first examples for testing purposes before taking ownership of its initial operational aircraft shortly after.

Since then, the type – colloquially known as the ‘Big Ugly Fat Fellow’ (or BUFF) – has formed the backbone of the service’s global strike and heavy bombing operations, seeing extensive combat use throughout the Vietnam and Gulf wars. It acted as a deterrence and retaliatory strike platform during the Cold War, exploiting the aircraft’s ability to carry and launch nuclear weapons. The USAF continues to employ the B-52 on missions around the world, with notable involvements in various operations, including Allied Force in the former state of Yugoslavia, Enduring Freedom in Afghanistan and Inherent Resolve as part of the military intervention against so-called Islamic State.

The air arm operates two other types alongside the Stratofortress: the variable swept-wing, supersonic-capable Rockwell B-1B Lancer and the stealthy Northrop Grumman B-2A Spirit. As of March 2020, the USAF employs 157 bombers, with the B-52H accounting for just under 50% of that total – 76 are in service with the USAF’s Global Strike Command (AFGSC) and Reserve Command (AFRC), based at Barksdale Air Force Base (AFB), Louisiana, and Minot AFB, North Dakota.

Development is progressing on the air force’s next-generation strategic stealth bomber – the Northrop Grumman B-21 Raider – under its Long-Range Strike Bomber (LRS-B) programme, with a first flight scheduled to take place in late 2021. With at least 100 examples sought, the platform will replace both the B-1B and the B-2A in operational service, but not the BUFF. The B-52H will be retained by the air force and used to complement the B-21, and will be kept relevant through modernisation. Upgrades – such as the ongoing campaign to re-engine the fleet and provide next-generation offensive capabilities – will also ensure the type is more efficient and cost-effective. These enhancements will enable this Cold War veteran to accomplish what no other frontline military aircraft has ever achieved – providing operational service for 100 years.

The Century Bomber

Gen Robin Rand, commander of AFGSC, explained how the upgrades will maintain B-52’s viability: “With an adequate sustainment and [modernisation] focus, including new engines, the B-52 has a projected service life through 2050, remaining a key part of the bomber enterprise well into the future.”

As part of this process, the BUFF will receive new radar and communications systems, advanced beyond-line-of-sight (BLOS) terminals and next-generation weapons.

Over the last decade, the B-52H fleet has been integrated with new computer architecture, real-time feeds and multi-function colour displays for all operator stations under the Combat Network Communication Technology (CONECT) programme. The latter provides more up-to-date mission updates, intelligence and threat data from multiple sources to bomber crews on active operations.

Alan Williams, a deputy programme element monitor with AFGSC, said CONECT will ultimately transition the bomber from using 1960s technology to the 21st century: “CONECT is the first major digital upgrade to the B-52, providing communication and situational awareness upgrades, as well as a digital architecture that will provide the foundation for future upgrades.” 

The USAF is also incorporating Link 16 – a NATO-standard tactical data communications link – to the bomber fleet, with flight tests using the software set to begin this year. The inclusion of this will enable the B-52 – one of the last USAF aircraft to be integrated into the network – to be more interoperable with military aircraft, ships and ground units belonging to the armed forces of NATO member states.

Enhanced Eyes and Ears

Raytheon has benefitted greatly from the BUFF’s modernisation, having been contracted by the USAF to replace the bomber’s communication terminals with new modern, nuclear-survivable systems that can utilise the US military’s anti-jamming communications satellites. The deal – worth US$442m – comes under the air arm’s Force Element Terminal (FET) sub-programme – a part of its wider Family of Advanced BLOS Terminals (FAB-T) project. The contract was awarded on January 16 and includes the incorporation of this technology on the RC-135 fleet.

The contractor was also selected to produce new active electronically scanned array (AESA) radars for the B-52, replacing its legacy Northrop Grumman AN/APQ-166 mechanically scanned system. Raytheon’s offer was selected over Northrop Grumman’s AN/APG-83 scalable agile beam radar (SABR) in the USAF’s B-52 Radar Modernization Program (RMP). It will be developed using technologies from the F-15C/E-equipped APG-63(v)3 and APG-82 AESA platforms, along with the APG-79, which is employed by the F/A-18E/F Super Hornet and EA-18G Growler. The bomber’s current system was designed in the 1960s and hasn’t been updated since the 1980s. With an AESA radar employed, the B-52 will have improved navigational reliability, along with an enhanced mapping and detection range. Raytheon states that the aircraft “will gain new eyes to find and fight the smaller, more agile adversaries of the digital age,” with the new platform increasing the number of targets it can simultaneously engage. Low-rate initial production (LRIP) is expected to begin in 2024.

Twilight for the TF33

The biggest change that the BUFF force will undergo though, will be integrating new, commercial off-the-shelf (COTS) business jet engines, which will be more fuel efficient, quieter, easier to sustain and reliable than the current legacy Pratt & Whitney TF33-P-3/103 turbofans.

Each Stratofortress is powered by eight of these engines, which first flew in 1959 under a test version of the North American B-45 Tornado light bomber. It entered operational service with the B-52H in May 1961, which holds the distinction of being the only BUFF variant to employ turbofan engines, with its predecessors being equipped with Pratt & Whitney J57-family turbojets. Compared with the J57, the TF33 is cleaner burning, quieter and had close to double the amount of maximum thrust than the J57-P-1W turbojets that were equipped on the B-52A. Since it entered service, the TF33 has accumulated more than 72 million flight hours, most of which were counted whilst powering the Stratofortress.

New Engines, New Era

In February 2018, the USAF officially launched its B-52 Commercial Engine Replacement Program (CERP). The government-led engine source selection campaign seeks to procure 650 kits to support its B-52H fleet throughout the remainder of its operational life – with each aircraft continuing to be powered by eight engines. Of the service’s 76-strong B-52 fleet, 11 will receive new engines under LRIP as part of the final phase of Initial Operational Test and Evaluation (IOT&E), with the remaining 65 going through the process in six full-rate production lots.

Boeing – the lead integrator of the solution – states that the modernisation will save billions in sustainment and fuel costs, whilst providing a 40% increase in operational range and a longer orbit time in the battlespace, giving the bomber a greater mission flexibility and decreasing its reliance on tanker aircraft. It is also intended to reduce the aircraft’s overall carbon footprint, making it 30% more fuel efficient and quieter. The CERP will also replace the B-52’s struts and nacelles, along with related accessories, cockpit instrument panels and controls. Boeing calculates that reengining the BUFF will save the service US$10bn between now and 2050.

According to the Director Operational Test and Evaluation (DOT&E) US Fiscal Year (FY) 2019 annual report, the programme “is built around a five-phase integrated test strategy designed to [maximise] operational test data collection during [a] prototyping phase.” The USAF is following a rapid prototyping strategy which will start with the development of “a Virtual Power Pod Prototype (vPPP) digital model for each candidate engine to assess two-engine, side-by-side pod design options.” The results of the vPPP will support the development of a Virtual System Prototype (vSP) – a full aircraft digital design model of the selected engine “to support a preliminary system design assessment”, which will then be followed by the physical modification of two B-52Hs to support initial aircraft performance, flying quality and structural test activities.

The three primary engine contractors vying for the contract comprise General Electric (GE) Aviation, Pratt & Whitney and Rolls-Royce. The companies were expected to deliver their initial aerodynamic models early this year – ahead of the air arm’s final selection, currently scheduled for January 2021.

Rolls-Royce has offered a variant of its F130 – based on its BR700 family of business jet engines, specifically the BR725. The USAF currently employs versions of the powerplant on its E-11A BACN and Gulfstream C-37A fleets, where it has accumulated more than 200,000 combat flying hours. The company states that the engines will be manufactured at a new assembly line in Indianapolis, Indiana, if it is selected.

GE Aviation is offering two platforms in its campaign to win the CERP contract, the CF34-10E and Passport respectively. The former is a scaled down and improved version of its CFM56 commercial engine family, which is employed by Embraer’s E190, E195 and Lineage 1000 aircraft. GE states that the latter is its “most advanced, digitally capable engine built on proven technologies [to deliver] game-changing performance and fuel burn in the most severe environments.” The Passport is employed by Bombardier’s Global 7500/8000 business jets.

Pratt & Whitney is presenting its PW800 turbofan, which is employed by long-range business jets including the Dassault Falcon 6X and Gulfstream G500/G600. Each engine is intended to make the B-52H more efficient and easier to maintain than its current legacy TF33 powerplants.

Next-Gen Weapons

Efforts to introduce the B-52 fleet to more modern weapons have been ongoing since 2006 with the Smart Weapons Integration Next Generation (SWING) programme. Its internal weapons bay is being upgraded so it can deploy GPS-guided smart bombs, transforming the common strategic rotary launcher into a conventional system, capable of carrying over 50% more precision guided weapons. It will enable the bomber to carry AGM-158 Joint Air-to-Surface Stand-Off Missiles (JASSM) and unmanned miniature air-launched decoys (MALDs). The launchers can be transferred between aircraft and can carry, target and launch up to eight Joint Direct Attack Munitions (JDAMs). The B-52 also has the option to be fitted with Lockheed Martin’s AN/AAQ-33 Sniper advanced targeting pod to improve its air-to-ground/air-to-air intelligence, surveillance and reconnaissance (ISR) capabilities. Furthermore, the service is said to be exploring the possibility of replacing its ALQ-172 electronic countermeasures system (ECM) with a more up-to-date alternative.

The USAF is also equipping the BUFF with wing pylons that can take a single munition weighing up to 20,000lb (9,071kg). This gives the bomber the ability to employ the GBU-43/B Massive Ordnance Air Blast (MOAB) large-yield bomb.

In referencing the B-52’s continuing nuclear role – as of 2020 – it is no longer authorised to carry B61-7 and B83-1 nuclear gravity bombs, as per the latest version of Air Force Instruction 91-111 (dated September 2019). Currently, the fleet is only permitted to employ the AGM-86B air-launched cruise missile and will be integrated with the Long-Range Stand-Off (LRSO) missile, which is in development. The LRSO is said to have stealth characteristics and can be configured with either a nuclear or conventional warhead. It is slated to fully replace the AGM-86B in service.

A Hypersonic ‘Mothership’

On June 12, 2019, the USAF conducted a captive-carry test flight with a B-52H, equipped with its AGM-183A Air-Launched Rapid Response Weapon (ARRW) from Edwards AFB, California. The bomber acts as a ‘mothership’ to a hypersonic boost-glide system using a rocket to accelerate to speeds in excess of 3,000mph (4,828km/h) before the payload separates and glides to its target. During the test, the missile was carried under the aircraft’s wing on a modified pylon. The ARRW is being rapidly developed by Lockheed Martin for the service, as it seeks to counter the hypersonic programmes under way in China and Russia.

Capt Darren Montes, commander of the 419th Flight Test Squadron (FLTS) and B-52H test pilot during the first ARRW test flight, said: “The B-52 continues to prove itself as a critical workhorse in the development of new capabilities for the nation. By virtue of [its] large external carriage capacity, it is an excellent platform for testing new vehicles and weapons, supporting the current and future needs of the operator… The [bomber] has a rich history of hypersonic testing, including the X-15, X-51 and many other experimental and research aircraft. [The ARRW] test and the increase in future hypersonic weapons continue that legacy.”

The service has scheduled the AGM-183A to reach an early operational capability in 2022, just four years after the project was commissioned. Will Roper, assistant secretary of the USAF for Acquisition, Technology and Logistics explained: “We’re using the rapid prototyping authorities provided by Congress to quickly bring hypersonic weapon capabilities to the warfighter. This type of speed in our acquisition system is essential – it allows us to field capabilities rapidly to compete against the threats we face.”

Introducing the B-52J?

The USAF is following a very rapid process in modernising the B-52H with many of its programmes taking place over a couple of years.

Bearing in mind the scope of the recapitalisation, the air arm has hinted that the modernised aircraft might receive a B-52J designation, though this has yet to be confirmed. Once thing is certain, though the type will outwardly retain its famous profile, the BUFF of tomorrow will be a completely different platform to that of its origins. These modifications will provide the stepping stones needed for the USAF to keep the B-52 reliant, relevant and viable for the next 30 years.