B-1B Bombers Can No Longer Fly At Low-Level And Their Annual Flight Hours Have Been Restricted

The B-1 was never designed for perpetual combat operations and it hasn't aged gracefully. Now major limits are being put on how and when they fly.

Tyler Rogoway

With the announcement of the potential imminent retirement of more than a quarter of the remaining B-1B bomber fleet, it’s a great time to look back at the rollercoaster ride the B-1 community has been on and to look forward to it’s looming sunset years. The United States Air Force is one of the world’s last remaining air arms to retain global power projection with a long-range bomber fleet and there are no signs it will give that up. B-21 Raider stealth bomber procurement is proceeding full steam ahead with the partial goal of replacing B-1s starting in the early 2030s. The sudden move by the Air Force to offer up 17 B-1s to the congressional budgetary chopping block has surprised some, but not all. So, how did we get here and how bad is the current state of the B-1B force?

On June 29th, 1985, at 1:55 PM, a B-1B nicknamed Star of Abilene was the first example of the bomber to land at Dyess Air Force Base, Texas as part of a delivery ceremony in front of an air show crowd of 45,000. Almost foretelling the B-1's legacy, legend has it that the real Star of Abilene was delayed by maintenance problems and another B-1 arrived in its place so as to not disappoint the crowd. 

With that first delivery, Dyess became, and still is, the center of the B-1 world. In 2003, 18 years later, the Star of Abilene was retired early with 33 of its stablemates as part of a plan to concentrate the B-1 budget to increase reliability. The bomber was towed through Texas’ red dirt and mud to get to the main gate for display where it remains today.

In total, 100 B-1Bs were built and 62 remain in service 35 years after the type’s introduction into service. In those three and a half decades, one of the worst kept secrets of the B-1 program was its poor reliability. 

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B-1B under construction at Rockwell's facility at Plant 42 in Palmdale, California during the mid-1980s.

The B-1B was resurrected from the canceled 1970’s B-1A program, which was originally intended to replace the B-52. When it was brought back in 1981, the bomber had become an interim measure due to the delays the Advanced Technology Bomber (ATB) program experienced. 

The ATB was funded at the time as “Aurora,” but was ultimately known to the public as the B-2 Spirit. When the B-2 was finally rolled out for the first time, it did so the same year as the 100th and final B-1B delivery, 1988. 

The B-1 dutifully took its place next to the B-52 in the nuclear deterrent role, until it stood its last nuclear alert in 1997. The bomber's first combat employment was shortly thereafter during Operation Desert Fox in Iraq in 1998.  After September 11th, 2001, B-1s quickly found their place in Operation Enduring Freedom. 

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B-1B seen sitting idle while deployed to the Middle East during the 2000s. 

In actuality, B-1s were already deployed to Guam for a global power exercise when the 9/11 attacks took place. They quickly moved to Diego Garcia in the Indian Ocean and in March 2002 the 9th Bomb Squadron from Dyess AFB participated in Operation Anaconda. Throughout operations in Afghanistan, and eventually Iraq, B-1s flew from Oman, Diego Garcia, Qatar, and other forward operating locations. Their loiter time, large payload, and ability to perform show of force flybys, as well as other unique capabilities, rapidly evolved them into one of the world’s most requested close air support platforms and a virtual flying arsenal ship. That’s a large contrast from the nuclear deterrent role for which the bomber was originally intended. 

Upgrades to precision weapons capabilities continued and proved useful. In combat, B-1s mostly employed GBU-31/B 2,000 pound Joint Direct Attack Munitions. Such large ordnance kept B-1 use in Iraq more limited. In 2007, the Sniper XR targeting pod was fitted to the right front-most external weapons hardpoint, greatly improving precision weapons delivery capabilities by self target acquisition. More recently, $1.26 billion was spent on long overdue avionics modernizations, called the IBS, or Integrated Battle Station, for the forward and aft B-1 crew stations.

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The B-1B's upgraded cockpit. 

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B-1B's upgraded rear crew station. 

B-1s were almost continuously deployed for 15 years and over 12,000 combat sorties have been flown to date. Ground commanders love the B-1 for always performing assigned taskings when needed, but the B-1 world was infamous for maintenance problems and low mission capable rates. 

In August 2019, only six of the remaining 62 B-1Bs were mission capable. The highest time B-1 has accumulated over 12,000 flight hours. Priority was given to keep jets ready for combat, but training is essential to readiness. An elaborate system including, but not limited to generating spare jets, ever-evolving maintenance inspection concepts, and cannibalization programs became essential parts of even peacetime operations as the jets continued to age poorly. A normal day on a B-1 flightline involves aircrews starting up perfectly good aircraft and routinely finding so much going wrong that they leave it for a spare, or even a spare of a spare. 

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A B-1Bs preparing to on a Red Flag mission out of Nellis AFB. Note the Sniper targeting pod on the forward fuselage pylon.

The original engineers expressed disapproval back in 1990 when they discovered active duty aircrews were performing touch and go landings. Remember, this jet was designed to sit nuclear alert. Combat jets and especially heavy bombers are purpose-built, life limited, and a finite resource. The service life expectancy of the B-1 fleet has already been extended several times. The bombers were never intended to see continuous use, to include conventional combat, for decades on end. 

Like all machines, B-1s wear out. Things like heavyweight landings have a price to pay. Even in the early days of the B-1B program, cracked longerons – the plane's backbones – and other structural problems were found. Many more structural issues have been discovered since, including wing spar tabs, lower wing skins, fuselage splices, longeron doublers, and upper wing splices.

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B-1B during phase inspection at Tinker AFB.

A single disused B-1, 85-0082, was removed from Edwards Air Force Base in 2012, partially disassembled, and trucked to Seattle where it would become a fatigue testing article, providing useful information about the health and longevity of the aircraft’s structure. Modifications, One Time Inspections (OTIs), and extensive Time Change Technical Orders (TCTOs) have since been implemented. Aircrew procedures have been updated many times as fleet management initiatives have been deployed. The B-1B scheduled inspection concept at home bases went from phase to isochronal and back again in a search for the best way to manage the aging fleet. 

Every B-1 in the United States Air Force inventory has been extensively inspected and rebuilt many times by Program Depot Maintenance (PDM) at Tinker Air Force Base in Oklahoma City. PDM generally happens every five years and jets head back to their home stations looking brand new. 

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A B-1B after a major overhaul at Tinker AFB. 

Bill Barnes, Director of the B-1 Systems Program Office, acknowledged that “It’s been flown past its certified service life and, as such, it’s developed numerous structural issues and we’ve been working on repairs for over the last four or five years.” 

In 2018, a B-1B, callsign Hawk 91, had a series of problems over Texas that resulted in the aircraft commander calling for the entire crew to eject. The first ejection summarily failed and the crew decided to stay together and land the jet in Midland, Texas. There were already issues with egress documentation and maintenance in previous years, but this failed ejection was traced to a part. Fleetwide groundings ensued. Three weeks later, the grounding was gradually lifted as the fleet was inspected and repaired as necessary. 

In addition to serious egress system problems, critical structural discrepancies have been a primary focus of the B-1 Systems Program Office at Tinker. Recently the 766th Aircraft Maintenance Group there stood up a dedicated repair line just to address B-1 structural issues. Before B-1s leave, they undergo 5,000 man-hours of repairs in only 30 days under phase 1. Phase 2 will begin in April 2020 and B-1s will receive 14,000 hours of repair work each. To meet these increased maintenance goals, the Tinker B-1 PDM will need to increase its workforce by 50 percent. The goal, at least in theory, is to keep the B-1 structurally capable of flying until 2040.

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A technician gives a tired Bone some much needed TLC at Tinker AFB.

A further implementation intended to keep the B-1 fleet going is a yearly flight hour limit imposed by General Timothy Ray, the Commander of Global Strike Command. Each aircraft will be expected to fly less than 300 hours per year unless waivered, according to a B-1B Fleet Management Policy Letter sent out to Ellsworth and Dyess Air Force Bases in January of 2020.

Global Strike Command stated the following to The War Zone regarding the B-1B’s material condition: “Over the last 35 years, the B-1B Lancer community has continuously reinvented itself as a premier long-range precision strike platform. However, continuous bomber support over the last 20 years has taken a toll on the airframe’s structure due to overuse in a manner not commensurate with it’s planned design.”

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B-1B undergoing an engine swap of one of its four F101 afterburning turbofans. 

One of the most taxing flight profiles on the B-1B airframes, according to the engineers, is low-level terrain-following flight. The ‘whiskers’ at the front of the jet are known as the Structural Mode Control System vanes (SMCS vanes), a further evolution of the YF-12’s shaker vanes tested at Edwards Air Force Base in the 1970s. 

SMCS Vanes react to a set of accelerometers in the nose and spine with hummingbird-fast movements intended to dampen structural oscillations, increasing airframe life and improving ride quality. The B-1B’s original mission was to penetrate under the radar at low-altitude and high-speed in any weather, day or night.

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SMCS or not, cruising at 540 knots at 500 feet above ground level regularly for 35 years has worn the B-1 fleet out in ways flying level at 20,000 feet and dropping JDAMS in combat never has. Almost all the low-level flying has been stateside during peacetime. Confusingly, the idea of using a B-1’s terrain-following radar and low-level capability to penetrate soviet air defense went away a long time ago. 

Nonetheless, B-1 aircrews continued to train for the entire life of the bomber by frequently flying low-level routes. Why? One reason is that it’s fun. Has a B-1 ever flown an actual combat low-level ingress to penetrate contested or denied airspace? It’s unlikely, but I stand to be corrected.

More to the point, the B-1 aircrew low-level training requirement has ended over structural longevity concerns. Lieutenant Colonel David Faggard, Air Force Global Strike Command top spokesperson, said: “We’re working closely with aircrews, maintenance, industry engineers and combatant commands to identify and determine what, if any, changes may be made as we balance operational necessity today with the longevity of the B-1 airframe for the future.” Faggard declined to comment on specifics, but The War Zone understands that a 5,000-foot floor for B-1 operations has now been implemented. 

The B-52 community largely gave up low-level training a long time ago. In their case, they had a much larger fleet, with 744 examples built and providing data points, so the accelerated airframe wear caused by low-level training couldn’t be ignored. The B-52, like the B-1A, and unlike the B-1B, was built from the outset for high altitude missions, which they may end up having flown for an entire century before they are retired. Meanwhile, the B-1 world is finally and quietly entering its twilight years.

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We reached out to an engineer associated with the B-1B program, who told us the following:

“In my own opinion after seeing in excess of 20 years of B-1 operations, we’ve accomplished more than the aircraft was really ever intended for, even if it wasn’t used in the originally conceived methods. The B-1 has been maligned, underfunded, and often placed under the charge of those who managed it poorly and didn’t represent it well when it came to sustainment and actual preventative measures for fleet health."

"The aircraft has largely overflown its original estimated service life and as B-1 operations will eventually dwindle into the twilight, many people will never know the amount of effort poured into keeping it flying despite the conditions, which forced it’s handlers to keep moving the goalposts. We were promised better systems through upgrades only to have them fail and no spares available. Procurement and sustainment contracts for critical components often took years only to have those parts not fit or fail sometimes out of the box."

"I’m anxious to see what’s coming, but also somewhat saddened by the sober knowledge I’ll watch these aircraft depart on their final flights.” 

Tyler Rogoway

U.S. Air Force General Timothy Ray, commander of Global Strike Command seems to agree B-1s were overextended. He said, “The ongoing inspections and TCTOs [Time Compliance Technical Orders] were a much-needed step back even though we lost a lot of flying.” He also mentioned that he’s hopeful mission capable rates will improve.

The most recent combat employment for the B-1B Program was a somewhat mysterious October 2019 rapid deployment by Bones from Ellsworth to Saudi Arabia, where the bombers supported the operation that resulted in the death of Bakr Al Baghdadi. During that mission, B-1s mostly lied in wait as F-15Es did the heavy lifting with stealthy JASSMs missiles.

As late-life maintenance obligations and complications pile up, B-1s have seen fewer and fewer deployments. When they deployed in 2019, they did so briefly and in small packages. More short strategic bomber rotations are planned. General Ray commented, “The deployments are short, they’re crisp, they’re not long and enduring." He doesn’t believe the missions will keep B-1s from undergoing maintenance. 

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Crews work on a B-1B deployed to the Middle East in support of the Global War On Terror. 

Regardless of decreasing expeditionary and combat use, a recent “expanded carriage demonstration” performed by the 412th Test Wing at Edwards Air Force Base hints at the potential for keeping the B-1B relevant until it is replaced by the B-21 Raider. But realizing that potential will cost even more money for a jet that is already being drawn down and is costing the Air Force plenty.

The Air Force’s new B-21 Raider stealth bomber is expected to be flying at Ellsworth AFB starting around 2025, if everything goes as planned, gradually phasing out and replacing B-1s sooner than later. 

The B-21s certainly has large shoes to fill, but from the outset of recent acquisitions such as the F-35, the Air Force has placed a strong emphasis on ease of maintenance and reliability, whether or not that will actually materialize is another question altogether. B-1 retirements are scheduled to begin in 2032 and go through 2038. What will the B-1’s golden years look like? With all the work being done at Tinker to keep B-1s able to fly until 2040 and the recently implemented flight restrictions, it appears that the B-1 fleet will be handled with deliberate gentleness. 

Tyler Rogoway

With all this in mind, enjoy seeing B-1s at air shows while you can. As of February 2020, the Air Force is already telling Congress it’s unwilling to pay for sustainment and structural improvement costs for 17 of the 62 B-1s and wants to send them to the boneyard at Davis Monthan AFB by the end of the year. It will either be forced by lawmakers to pay for keeping the bombers flying or the sunset years of the B-1 fleet will consist of 45 of the original 100. However many are left, they will be carefully operated and delicately maintained to last as long as needed. One more unpredicted fleet-wide structural problem could be more than the Air Force wants to pay for and it is very possible the fleet could be drawn down before the current plans dictate, depending on how it actually ages. 

The pride of the B-1 universe has always been deeply rooted in its combat-proven ability to get whatever is asked of it done in the face of complex maintenance challenges. Inarguably, B-1s are very, very used. A day when the final B-1 flight will take place is now on the horizon and elaborate sustainment practices will be increasingly necessary to keep that date from coming to pass sooner than anyone currently wants. 

Tyler Rogoway

Contact the editor: Tyler@thedrive.com