B-1B upgrades get $146.9 million as USAF bridges to B-21

The Air Force is paying more to keep its B-1B Lancers flying while it waits on the B-21 Raider, Simple Flying reports. On Sept. 25, Thomas Instrument of Brookshire, Texas, won a $23.5 million contract to overhaul control surface sensors on the bombers through September 2031.

The sensor work sits alongside the service's fiscal 2027 request, which includes $146.9 million for modifications to B-1Bs already in service. Simple Flying reports that is effectively double the $73.9 million requested a year earlier. The aim is to keep the B-1 flying until at least 2037.

The immediate problem is airframes. Simple Flying reports the Air Force recently fell below 5,000 total aircraft, the lowest count since World War II. B-52 modernization is delayed, and Operation Epic Fury exposed gaps in the current inventory.

The sensors regulate the Lancer's flap brakes. Tinker Air Force Base in Oklahoma handles logistics for the program, and Thomas Instrument builds the parts in Texas, Simple Flying reports.

The $23.5 million is a ceiling, not a commitment. Simple Flying reports that no defense dollars were obligated when the award was announced, and that earlier work on the same systems ran around $700,000 to $900,000.

Thomas Instrument also won a separate contract worth just over $25 million for B-1B hydraulic heat exchangers. Simple Flying reports it was the sole bidder for the flap sensor work and one of two bidders on the heat exchanger contract.

A thin supplier base

That narrow field of bidders is a known problem with older aircraft. Simple Flying notes the B-21 is meant to fix it through open systems architecture and modular design, which should make this kind of retrofit cheaper and less complex.

The retirement plan reversed

The Air Force once planned to retire the B-1B and the B-2 in the early 2030s as B-21s arrived. Fiscal 2027 documents reverse that, proposing $342 million for B-1 modernization across 2027 to 2031, and nearly $1.7 billion for the two bomber types together. The B-2 accounts for $1.35 billion of that.

Demand drove the change. Simple Flying reports the Mitchell Institute for Aerospace Studies has noted rising demand for bombers on routine task force rotations and operations like Midnight Hammer. After the June 2025 strike on Iran's nuclear sites, the service made a record request above $1.5 trillion.

The fleet is down to 44 aircraft

The active B-1 fleet is 44 aircraft, down from a production run of 100. The fiscal 2026 defense authorization bill barred any more B-1B retirements through 2030, and lawmakers have since required the same fleet count through 2037.

Availability is tight. Simple Flying reports the mission-capable rate stood at 43%, down from 55% in fiscal 2022, which leaves roughly 19 aircraft ready on a typical day. Air Force Global Strike Command started the North Star Readiness Campaign, aimed at supply chains and depot maintenance.

The B-1 carries 75,000 pounds (34,019 kg) of weapons, the largest conventional payload in the Air Force inventory. It lost its nuclear mission under legacy treaties, though Simple Flying reports lawmakers are weighing feasibility reports on restoring it.

B-1Bs flew nonstop strike missions from Ellsworth Air Force Base in South Dakota during Operation Epic Fury, the campaign against Iran. At the peak, about two dozen bombers went to RAF Fairford in England, 18 of them B-1Bs. Simple Flying reports that was 41% of the 44-aircraft fleet. The aircraft were ordered home after a security threat to the British base.

The structural work

The largest known structural effort is the BackBONE Project. A B-1B returned to service after crews replaced its forward intermediate fuselage, a 33-foot (10.1 meter) section of the upper spine ahead of the variable-sweep wings.

The National Institute for Aviation Research at Wichita State University worked on the engineering, using digital sequencing and a physical prototype before maintenance crews cut into the aircraft. Planners set a 12-month turnaround and finished ahead of schedule, Simple Flying reports.

What to watch

The first B-21s are due at Ellsworth Air Force Base in 2027. A $4.5 billion funding injection raised initial production capacity by 25%, and Simple Flying reports the line is expected to settle near seven aircraft a year. Discussions have begun about raising the planned fleet from 100 to 145 or 185.

Replacing the 44 B-1Bs one for one would take more than six years of factory output before the 19 B-2s are addressed. Two milestones decide whether the stopgap holds. The first is funding: whether lawmakers back the B-1 modernization programs. The second is timing: whether the initial B-21s reach the fleet on schedule next year.

• B-1B Lancer
• B-21 Raider
• bomber fleet
• Thomas Instrument
• US Air Force