Planning the US bomber fleet of the future will be a long process, and current aircraft may have to last 40 more years
Paul Lewis/WASHINGTON DC
The US bomber constituency has been watching more closely than most the outcome of this year's seemingly perpetual presidential election. Riding on the outcome is the future direction of the US Air Force's bomber roadmap. In lieu of a political kickstart for a new programme, the fleet of Northrop Grumman B-2 Spirits, Boeing B-1B Lancers and venerable B-52H Stratofortresses will soldier on for almost 40 more years.
The USAF does not plan to generate a mission needs statement (MNS) for a replacement bomber before 2014. Actual production would not start for another two decades, with initial operational capability pencilled in for 2037. By then, the air force estimates it will no longer be able to muster the 170 aircraft needed to ensure a combat-coded threshold of 130 bombers.
The cost of developing an all new B-3 bomber is steep: The Analytic Science Corporation puts the price of non-recurring research and development alone at $35 billion - excluding production. Lexington Institute chief operating officer Loren Thompson says this will be further compounded by the mounting expense of maintaining ageing B-52 and B-1 fleets out to 2037, which he contends will push the final bill close to $220 billion by 2050.
"For $47 billion, the air force could build 80 more B-2s, get rid of older planes and have a much more capable fleet of 100 stealthy bombers with greatly simplified support requirements," says Thompson. The cost of the alternate plan, including both procurement and operating an "improved B-2" alongside the Spirit over the next 50 years, is estimated by Lexington at $120 billion.
Even if a new administration expedites a decision to restart B-2 production, the first aircraft could not be delivered until after the next presidential election in 2004. It is likely to be 2020 before the final B-1s/B-52s could be pensioned off. The USAF, in the interim, would have to continue investing in upgrades to the current fleet, without which most of the bomber force would be grounded by obsolete equipment.
There are 208 bombers in the USAF inventory today, including 18 B-52s which it considers surplus but is prevented from retiring by US Congressional action. The air force is now juggling its finite resources to bolster the number of combat-coded bombers from 112 to 130 by 2005, mainly by "buying back" training and attrition reserve B-1s.
Under the present roadmap, the USAF is confident it can sustain its force of 130 bombers for a further 37 years. This, in part, is based on the optimistic prediction of losing only one B-1 every five years and one B-52 and a B-2 every decade. This could require pilots to throttle back on how hard and low they drive their aircraft, particularly the swing-wing Lancer.
B-1 attrition has been averaging one aircraft every two years, mainly as the result of pilot error, with the fleet having declined from 100 to 93 units over the last 14 years. The roadmap also assumes linear utilisation at peacetime levels, whereas in reality USAF bombers have been committed to intense periods of combat twice in the last 10 years - in the Gulf and, more recently, over Yugoslavia.
"Right now we're saying we don't need to replace the aircraft until 2037. The attrition model we use is for peacetime only, so if we do take on combat losses, if the threat changes drastically, or if the technology alters how we use bombers and the munitions we put on them, it could drive differences in that time," says Maj John Bernier, USAF B-52 programme element monitor (PEM), Directorate of Operation Requirements.
The 1999 bomber white paper outlined a series of near-, mid- and long-term planned enhancements to sustain the fleet over the next 15 years. The Kosovo conflict, in which all three types of aircraft played a significant part, has served to move many of these items further up the priority list. Funding is a perennial problem, though, and the bomber modernisation budget is still short of approximately $3.3 billion.
B-2 - The Golden Bullet
The B-2 is the youngest member of the bomber troika and by far the smallest fleet. Escalating costs and defence cuts have progressively reduced the original planned procurement from 133 to just 21 stealth bombers, with the final example being finished in 1998. Attention has since been focused on upgrading the fleet to the much more capable Block 30 configuration. By June, all but one had been completed.
The last Block 20 aircraft, the Spirit of New York, remains at Edwards AFB, California, and is employed as a test aircraft. By the time it is finally upgraded in 2002, it will in fact represent a 'super Block 30' aircraft, having been configured to test many of the B-2's future modifications. Post Block 30 improvements are targeted in three main areas - supportability, connectivity and weaponry.
Northrop Grumman B-2 programme manager Paul Marchisotto says: "The most prominent improvement is the use of advanced high-frequency material, which is a pretty significant change to the low observability system of the aircraft. It allows the use of standard access panels and fastener heads without maintainers having to fill and tape over gaps between panels and the airframe."
A higher fidelity design has produced a very small and controlled panel recess cavity, while fasteners have been tipped with magnetic radar absorbing material so as not to degrade the B-2's radar cross-section. Work that once took days to complete can now be finished in hours. The technology was originally intended for Northrop Grumman's stillborn Joint Strike Fighter (JSF) contender, before being adopted by the B-2 and later the Lockheed Martin/ Northrop Grumman/BAE Systems JSF bid.
The B-2 was conceived as an independent nuclear bomber, but with the end of the Cold War it has transitioned to a conventional role dictating better interoperability. Block 30 opened an ultra-high frequency channel of communications to the space-based Milstar. Next on the list is a Link 16 capability and a new extremely high frequency (EHF) system due to be selected by mid-2001 and to come onlineby 2008.
With US-based B-2s typically flying 30h endurance bombing missions during the Kosovo conflict, the ability to receive mid-mission updates on targets or routing is critical. As part of this effort, the B-2 is getting a new centre console 200mm x 250mm (8in x 10in) liquid crystal display (LCD) for en route flight and mission planning.
The third improvement is to further broaden the B-2's payload. Block 30 added the 900kg (2,000lb) Mk84 member of the Boeing Joint Direct Attack Munitions (JDAM) family. The B-2 can carry 16 of these precision- guided bombs and, with the addition of new smart racks, this will increase to 80 of the new smaller 225kg Mk82 JDAMs.
Bunker buster
Other new additions to the B-2 weapons bandolier include the 130kg EGBU-28 2 bunker buster replacement for GBU-37/GAM-113 and the Raytheon AGM-154 Joint Stand-off Weapon (JSOW). In the planning pipeline for integration in 2002 is the new Lockheed Martin AGM-158 Joint Air-to-Surface Stand off Missile (JASSM).
None of these programmes is yet fully funded through to completion, other than the earlier Block 30 upgrade. For this reason, the air force has resisted packaging these improvements into an all-encompassing Block 40 upgrade. The B-2 modernisation is short by as much as $500 million, forcing the programme to pursue separate upgrades incrementally rather than as a co-ordinated effort.
"We're highly constrained by funding," says Marchisotto. "We could get there quicker with everyone working on the aircraft at the same place and time, but that puts an even higher burden on earlier year costs and those are the years that are in contention right now."
Beyond fiscal year 2006, the air force has longer-term improvements in mind. These include swapping out the B-2's 1980s computer processors and proprietary avionics architecture for a commercial off-the-shelf plug and play capability. This would increase processing power and reduce support costs. As yet there is no funding, however.
One enhancement that is being given greater importance is an electronic digital engine control capability. The analogue controllers for the B-2's four General Electric F118-100 powerplants are proving increasingly difficult to support. "This is listed as a mid-term item, but we'll probably have to bring it into the budget in the next year or two as it's a 'fact of life' improvement we must make before 2004," says Maj Jeff Kindley, B-2 PEM.
Structurally, the aircraft has a long way to go before the USAF starts to eat significantly into its 40,000h airframe lifetime. The drag-rudder attachment points are predicted to fail first, followed by the aft engine deck, which is subjected to the greatest vibro-acoustic stress.
"We're undergoing an analysis of what we would do if a problem arose and we continue to look at ways to extend the life of the vehicle," says Marchisotto. "The way they are currently being used, they'll probably make 2037, but if we have more Kosovos, we will not make it."
B-1 - Interdictor Workhorse
The swing-wing B-1B provides the backbone of the USAF's conventional interdiction force, with 93 in service with the USAF and Air National Guard. The fleet is now midway through the Block D upgrade, adding anti-jam radios, a global positioning system and a 1760 databus weapons capability to enable JDAM to be carried. The depot-level retrofit is due to wrap up by early 2003.
A parallel effort is adding the Raytheon ALE-50 towed decoy to the B-1, with 22 aircraft retrofitted to date and the rest to be completed by late 2004. The wide-band repeater system made its combat debut last year in the Balkans installed on seven Lancers operating from RAF Fairford in the UK. With the USAF's entire JDAM stock committed to the B-2 during the Kosovo air campaign, the B-1 was relegated to using non-precision weapons and accounted for some 30% of all expended Mk 82 bombs.
Flight testing of the next "Block E" upgrade is due to start shortly at Edwards. This is focused on re-equipping the aircraft with a new PC-based avionics computer and new modular core software by 2005. It includes the General Weapons Interface System, providing the ability to carry a mixed load of Lockheed Martin Wind Corrected Munition Dispensers (WCMD), JSOWs and, in 2003, JASSMs.
"Block E adds the functionality to carry the three types of weapons in the bay," says Rich Parke, Boeing B-1B director of business development.. "Currently on the B-1, if you wanted to carry three different weapons, you would have to reload a mission tape in flight, which is an eight-minute type of deal. Block E allows you to take off with WCMD, JSOW and JASSM and launch nearly simultaneously."
Running almost concurrently with this will be Block F flight testing, which is due to start next April using a separate B-1 test aircraft. A third Edwards B-1 test aircraft will marry the two blocks together. At the heart of Block F is the Defensive System Upgrade Programme (DSUP). It uses the BAE Systems ALE-55 fibre-optic towed decoy, Lockheed Martin ALR-56M radar warning receiver and ALQ-210 receiver/processor to generate deceptive technique jammings technique.
Boeing is the prime integrator for all three blocks, but unlike D and E, DSUP is not fully funded and needs a further $667 million to complete production. "The air force had decided to cancel the programme as part of the 2002 budget deliberations because we couldn't afford it," says Maj Brian Donahoo B-1B PEM. "We came to a deal to fund development and then look again at the production issue in 2004."
Even less well defined at this stage is a proposed Block G upgrade, which could encompass up to a total of 15 different items. The three major enhancements in order of air force priority would be the addition of a datalink, modernisation of the B-1's cockpit and upgrade of its radar.
Integrated solution
The USAF is looking at adding both Link 16 and a beyond-line-of-sight datalink. The latter uses a satellite to supply real-time mission updates for a B-1 entering a theatre of operations at the end of a lengthy transit flight. Both Boeing-supplied Link 16 and beyond-line-of-sight datalinks have been demonstrated on the B-1 during recent experimental exercises and in Kosovo. Full funding for an integrated solution has yet to be secured.
An upgrade of the B-1's monochrome-display 1970s-based cockpit has also been discussed. Many of the aircraft's instruments are obsolete and virtually unsupportable, such as the vertical situation display. Boeing would like to fit seven or eight commercial 200mm x 250mm multifunction LCDs, militarised for night vision goggles. Moving map, situational awareness and tactical data could be displayed at any station, while an interactive attack planner would enable the crew to accept, review and modify data linked to the bomber.
The third major wish item is to upgrade the B-1's Westinghouse APQ-164 radar with new processors. "What we're proposing is putting in the major components from the [Lockheed Martin] F-16 Block 60 and going to a highly integrated SAR [synthetic aperture radar], getting a higher resolution [1m versus 3m today], more throughput and then you could also have a multiple moving target track," says Parke.
The pacing of this upgrade is largely budget-driven; these three items alone cost almost $1 billion, says Boeing. The benefits would be to significantly broaden the B-1B's capabilities into new roles such as a future controller of unmanned combat air vehicles for which its four-man cockpit would be ideal.
Boeing has also proposed an electronic warfare (EW) version of the B-1B as part of the ongoing analysis of alternatives for replacing the Northrop Grumman EA-6B. "It's got the ability to penetrate and it's got a whole punch of reserve power and volume after we complete Block F," says Parke. "Therefore it would make sense to do a Prowler type of mission."
As a supersonic low-level bomber, the B-1B has a shorter structural life than either the B-2 or the B-52. The air force has so far used up about one-third of the aircraft's current 15,200h lifespan "We've told them to restrict low-level flying to preserve the structure," says Parke. "We don't predict any major structural failures until 2037, when we would have to replace the lower wing skins."
B-52 - The Stand-off Sentinel
The B-52H is by far the oldest of the USAF's bomber trio, the last of 744 examples having rolled off out of Boeing's Wichita plant in 1962. There are now only 94 aircraft still in service, the earlier B-52G having long been retired to the boneyard. This number is set to decrease to just 76 aircraft by 2007 for the USA to comply with the START II arms reduction treaty. There is talk of converting some of the 18 spare airframes to EW platforms.
Fearing that the B-52 will be offered up as a START III sacrificial lamb, the air force plans to fly on with the remaining aircraft until 2045 and perhaps beyond. By this stage, the youngest members of the fleet will be about 80 years old. Having been conceived in the 1940s, the aircraft will have a "design-to-demise life not much less than the timespan between the Wright Brothers' flight at Kitty Hawk in 1903 and today," says Thompson.
The B-52H now has a projected airframe lifespan of 37,500h, limited primarily by the wing upper skin. The fleet averages 15,000-16,000h three times its original design limit. "Overall, the structure of the aircraft is in good shape, but avionics are way outdated and a lot of the electrical circuits are getting pretty old and creating problems," says Donnie Saal, Boeing B-52 project manager, weapons/navigation.
Boeing is undertaking a study of completely rewiring the aircraft and possibly even adding a glass cockpit. In the shorter term, an $108 million Avionic Midlife Improvement (AMI) effort is focused on "fact on life" system changes. This includes replacing the aircraft's inertial navigation system (INS) with a new strap-down Honeywell system within five years. "The current INS is unsupportable and needs to be replaced by 2005, otherwise the jets will stop flying," says Bernier. "The programme is underfunded pretty much from 2002."
Other AMI items include replacing the B-52's old processors to increase memory and throughput, as well as upgrading flight and weapon software. The aircraft will be outfitted with a new data storage device, permitting random access for the the first time.
Running concurrently with AMI is the Situational Awareness Defensive Improvement (SADI) upgrade of the B-52's low/medium- band electronic countermeasures (ECM). This will replace the broad band ALR-20 receiver with Lockheed Martin Federal Systems' ALQ-210 system. Replacement of the Dalmo Victor ALR-46 is also being considered.
The high-frequency end of the ECM Improvement (ECMI) effort is being addressed by improving the ITT ALQ-172 receiver/jammer. Independent of SADI and ECMI, the USAF's Warner Robins Air Logistics Center is funding a Northrop Grumman upgrade of the existing manual ALQ-155 receiver/transmitter, boosting power and jamming techniques.
ECMI and AMI remain underfunded by $380 million, and a further $800 million is required to retrofit the B-52 with Link 16 and EHF from 2004. Adding a datalink will serve as a building block for the planned Enhanced Bomber Mission Management (EBMM) system. "The basic objective of EBMM is to be able to reassign and re-target weapons from an airborne state," says Saal.
Despite its advanced age, the B-52 remains an indispensable member of the USAF bomber triad. While its days as a penetrator bomber are over, it offers a formidable stand-off capability, as witnessed during Kosovo. It is still the only USAF aircraft capable of carrying the Boeing AGM-86B/C cruise missile, the nuclear-tipped Lockheed Martin built AGM-129 advanced cruise missile or its AGM-142 Havenap stand-off missile.
Adding weapons to the B-52 is comparatively inexpensive because of its size and large volume. It is the first of the three bombers to be armed with WCMD, which with JDAM is now carried externally. There are plans to extend the carriage of 1760-type weapons to the bomber's internal bomb bay. Other additions to the weapons inventory will include JSOW from 2001 and JASSM in 2002-03.
Source: Flight International
