AFRL Wants to Capture College Creativity in Maturing AI for Autonomous Systems

Nov. 24, 2021 | By Amanda Miller

An $88 million deal with the University of Dayton will hopefully “add a unique fresh look” at maturing artificial intelligence for Air Force autonomy applications.

The agreement between the Air Force Research Laboratory and the University of Dayton Research Institute—a program called Soaring Otter—expands on what Kelly Miller of the AFRL Sensors Directorate characterized as “existing research challenges.” Ranging from students to “extremely experienced technical experts,” Miller told Air Force Magazine by email that the university group’s “very diverse and capable teammates” factored into its selection.

“University partners are always a good way to get fresh ideas and re-energize the research, looking at different perspectives to solve a nagging problem,” Miller said.

Without naming any specific programs the research might benefit or offering any concrete expected outcomes, Miller said the researchers bring the “unique fresh look at complex problems” related to three of the five “transformational capabilities” the Air Force listed in its Science and Technology Strategy released in 2019:

Global persistent awareness, “which may include advances in ‘multimodal sensing’ and developing new laser and multistatic radars,” according to the Air Force
Resilient information sharing, “which may include developing mesh networks and ‘agile systems with real-time spectrum awareness’”
Rapid, effective decision-making, “which may include advances in artificial intelligence, machine learning, and predictive data analytics.”

Miller said Soaring Otter will involve “fundamental through advanced research areas” and “provide expertise in several areas including machine learning”—a branch of artificial intelligence—“to advance, evaluate, and mature Air Force autonomy capabilities.”

In its announcement of Soaring Otter, the university said technologies such as machine learning, artificial intelligence, and neural networks can help autonomous systems gather and process information and “then use the information to solve a problem or execute an action to achieve a goal.”

The name Soaring Otter symbolizes the program’s aim of “making major advancements, taking the technology to the next level, reaching the unexpected,” said Miller, who also acknowledged a personal interest in otters.

At the same time AFRL has brought in the University of Dayton to aggressively advance AI specifically for autonomy, the Department of the Air Force has taken up residence at the Massachusetts Institute of Technology to help advise and do research as part of 10 AI research projects while exposing more people from around the Air Force and Space Force to AI.

Average Age of USAF Aircraft Drops Slightly, But Eight Fleets Now Exceed 50 Years Old

Nov. 23, 2021 | By John A. Tirpak

Purchases of new F-35 fighters, KC-46 tankers, and C-130 transports in recent years have made only a small dent in the age of the Air Force’s fleet, down to 29.1 years across all types after hitting 30.55 years in 2020. But the service operates eight fleets exceeding an average of 50 years, and one—the KC-135—now exceeds 60.

According to data supplied to Air Force Magazine, the AT-38/T-38 trainers, the B-52 bomber, and aircraft based on the C-135 series—the KC-135, NC-135, RC-135, TC-135, and WC-135—are all in their mid-to-late 50s, with the KC-135 ringing in at 60.35 years of age. The B-52 is not far behind the Stratotanker, with an average age of 59.8 years. The data were current as of Sep. 30, the end of fiscal 2021.

Altogether, the Air Force operates eight fleets more than 50 years old; 13 more than 40 years old; 22 fleets older than 30 years; and 31 fleets more than 20 years old, on average. The remainder average less than 20 years old.

The raw numbers don’t tell the whole story, however. For example, the E-8 Joint STARS fleet is listed as having an average age of 20.8 years, but that only dates the inventory to when the Air Force acquired it; the Joint STARS were built on ex-commercial 707s that had already seen long service but were reconditioned before being configured as E-8s. The C-5M fleet is based on C-5As built in the 1960s and ’70s and C-5Bs built in the 1980s, then modified to the Super Galaxy configuration with new engines and structural enhancements. That fleet is listed as 35.14 years old, on average.

The youngest fleets in service are the KC-46, at 1.48 years old; the HC-130, at 4.0 years old; and the F-35, at 4.34 years in average age across some 302 aircraft. The Air Force also has a single AT-6 at less than a year old and three aircraft listed as “P-9A”—possibly PC-9 trainers—at five years old. The average age of the MQ-9 Reaper fleet of remotely piloted aircraft is given as 6.05 years across a fleet of 323 airplanes. Although the Air Force has accepted at least one MH-139 VIP/missile field support helicopter for testing, it is not listed on USAF’s tables. The two F-15EX fighters delivered this year are listed as “0.5” years old.

Air Combat Command’s F-15Cs ring in at 37.69 years old, and the F-15E Strike Eagles are 30.99 years old, on average. When they were new, both fleets were initially expected to serve about 12-15 years.

The B-1B and B-2A bombers are now 34.05 years old and 27.29 years old, respectively. Although the service retired 17 B-1Bs in fiscal 2021, that didn’t affect the average age much because those drawn down were already among the youngest of the fleet, built over a four-year period in the 1980s. Similarly, the 20 B-2s were all built in the mid- to late 1990s. The B-52Hs will likely reach 100 years of service, as they will soon be equipped with new engines and radars and are planned to serve into the 2050s.

Other types targeted for replacement in the coming few years include the E-4B flying command post, now at 47.38 years average age, and the E-3 AWACS at 42.99 years; USAF leaders have spoken in recent months about replacing the AWACS with the E-7 Wedgetail now serving in Australia’s air force. Although the AT-38/T-38 fleet is nearing 60 years, the Air Force anticipates it will take until the early 2030s to replace them with the T-7A RedHawk, and the last T-38Cs, upgraded with new displays, wings, and other improvements, may reach 70 years of service.

“The excessive age of the Air Force aircraft inventory is the result of decades of neglect,” said retired Lt. Gen. David A. Deptula, head of AFA’s Mitchell Institute for Aerospace Studies.

“Recapitalization and modernization … was deferred due to choices” made by Pentagon leaders “in favor of near-term priorities,” resulting in the gradual aging of the inventory over three decades, he told Air Force Magazine.

For the last 27 years, the Department of the Air Force was given less funding than the Departments of the Army or Navy, Deptula noted.

“The situation is now chronic and must be addressed,” he said. An Air Force that’s “relevant to dealing with the threats facing the nation … [is] fundamental to any successful joint military operation.”

The Pentagon, he said, can “no longer ‘kick the can down the road.’ The Air Force must be resourced to modernize its force, or its fragility will limit our ability to execute the national defense strategy.”

Upgraded Missile Warning Satellites Come ‘Another Significant Step’ Closer to Reality

Nov. 23, 2021 | By Amanda Miller

The Space Force’s “go fast acquisition” of three new missile warning satellites passed a system-level critical design review Oct. 28 that judged how the satellites and associated ground systems will work together and how the new equipment will work with existing missile warning systems.

Lockheed Martin received the contract to design the Next Generation Overhead Persistent Infrared (OPIR) Geosynchronous Earth Orbit satellites, which it calls NGGs, in 2018 for $2.9 billion. They’re the first batch of modern satellites meant to improve on and eventually replace the current Space-Based Infrared satellites, also built by Lockheed Martin. The contract was modified to add $4.9 billion in January 2021 for production and storage of the satellites, engineering related to launch, an interim ground system, and early on-orbit checkout of the satellites.

The satellites themselves and the payloads for the first two had already passed critical design reviews, Lockheed Martin said in a news release Nov. 23. The system-level review represented “another significant step” toward the first launch, planned for 2025, the company said. The review “specifically addressed the integration between the space and ground segments in addition to the integration of the Next Generation Interim Operations Ground System” with legacy systems.

The satellites are designed with “improved warning” features to detect missiles that move faster or create a dimmer infrared signature than current systems are designed to track, according to the release. The satellites were designed within the framework of Lockheed Martin’s LM 2100 Combat Bus, which can weigh from 5,070 to 14,330 pounds, according to Lockheed Martin. The satellites will also feature “enhanced resiliency and cyber hardening,” according to the company.

Upgrading the U.S.’s missile warning systems matters now because other countries are “finding ways to make missile warning more difficult,” said Joseph Rickers, Lockheed Martin’s vice president and program manager for the three NGG satellites, designated as Block 0, in the release. “They are also posing threats to space assets themselves.”

The Russian government acknowledged testing an anti-satellite weapon Nov. 15 that not only showed it could destroy a satellite in low Earth orbit but also created an extensive new debris field that U.S. officials and other world governments said will place space missions at more risk for years to come.

NGG satellites will travel in geosynchronous Earth orbit, farther than the Russian anti-satellite weapon system is suspected of being able to reach.

The Next-Gen OPIR isn’t the only effort attempting to field new missile-warning satellites. The Space Development Agency is planning a “Tracking Layer” as part of its National Defense Space Architecture of smallsats.

Eight wide-field-of-view infrared satellites are planned as part of a 28-satellite constellation in low Earth orbit that the SDA pegged for launch in 2022. The 28 are expected to form “the initial kernel” of the architecture that could ultimately number close to 200, with 40 to detect missiles. L3 Harris and SpaceX received $193 million and $149 million respectively to each build four of the infrared satellites. A test of an infrared sensor launched in August.

Data Hackathons to Help Expand Digital Engineering in the Testing Community

Nov. 23, 2021 | By Amanda Miller

So-called “hackers” from three commands competed in a hackathon Nov. 1-5 to help the Air Force Test Pilot School figure out how to manage stores of data in an expansion of digital engineering.

The Air Force Test Center, which operates the school, wants to expand digital engineering from something largely done for testing “into a more collaborative approach between the test units, program offices, and contractors,” according to a news release by center. “This requires appropriate data collection, storage, transport, and sharing at the right security levels.”

Digital engineering, put simply, leaves behind blueprints in favor of continuously evolving digital models.

About 40 troops, government civilians, and contractor employees “merged their different abilities” and came up with ideas for how to analyze data across different data sets, to share data, and to “automate certain activities for increased speed,” said Air Force Col. Keith M. Roessig, the center’s vice commander, in the release.

The hackathon also provided an opportunity for professional development—experience in cloud computing, software coding, and data analytics—as well as to “build a technical community,” the center said.

The hackers “all did a great job of recognizing each other’s strengths and using that knowledge to assign tasks,” said Brandon Stiles, chief engineer for the Test Support Division of the Air Force’s Arnold Engineering Development Complex, Tenn., one of the three commands that took part, along with the 412th Test Wing at Edwards Air Force Base, Calif., and the 96th Test Wing at Eglin Air Force Base, Fla.

They collaborated remotely over the Air Force Chief Data Office’s VAULT cloud platform, which gets its name from its description as making data “visible, accessible, understandable, linked, and trustworthy.”

The participants “were key in helping to examine test data formats from other test mission areas and demonstrating the ability to quickly convert data formats that could be used with Python automated analysis tools,” Stiles said.

Now the center plans to stage quarterly hackathons with the next goal “to not only have more participants, but to work with squadrons and hopefully get a bigger mission impact,” said the Capt. Troy Soileau, chief data officer of the 96th Cyber Test Group, in the release. The next hackathon could be as soon as the first quarter of 2022.

The Air Force first launched a white-hat hacking program in 2017, following up on the Defense Department’s first Hack the Pentagon event. Last year, hackers were invited to take control of a DOD satellite in the first-ever event focused on space-based capabilities.

Air Force Extends Deadline to Apply for the Rated Prep Program

Nov. 23, 2021 | By Amy Hudson

Active-duty Airmen who want to become pilots, combat systems officers, air battle managers, or remotely piloted aircraft pilots now have until Dec. 31 to apply for the Rated Preparatory Program.

The program gives Airmen who are interested in cross-training into rated career fields a chance to learn basic aviation skills. It is slated to run March 20-25 and March 27-April 1 in Denton, Texas, according to a USAF release.

“The Rated Preparatory Program provides a unique opportunity for officers and enlisted personnel to become rated officers,” said Brig. Gen. Brenda P. Cartier, Air Education and Training Command’s director of operations and communications.

The Air Force launched the program in partnership with the Civil Air Patrol in 2019 in an effort to tackle the service’s lingering pilot shortage.

Chief of Staff Gen. Charles Q. Brown Jr., a former F-16 instructor pilot at the U.S. Air Force Weapons School and the first Black uniformed leader of any U.S. military service, has pushed the Air Force to diversify the entire force. However, he’s acknowledged that the service has made little progress with its mostly white and male pilot corps.

“When I was a captain, I did an interview for Air Force Times, and it talked about the percentage of African Americans that were pilots,” Brown said during a December 2020 virtual town hall on racism and discrimination. “It was 2 percent. That was 30 years ago. You know what it is right now? It’s still 2 percent.”

There are many reasons the Air Force has struggled to get more minorities in its cockpits, including the prohibitive cost of flying outside of the military and a lack of exposure to aviation or to other people who fly.

“Through RPP, qualified Airmen gain skills they may have not had the opportunity or resources to gain before entering the Air Force,” Cartier said in the release. “We want to provide our Airmen the tools to pursue their lifelong dream of flying in the Air Force—a dream they may have never thought possible.”

Airmen selected for the program will receive ground training as well as eight flight hours in a Civil Air Patrol Cessna 182 Skylane as well as time in simulators. The idea is to make participants more competitive for rated selection boards, according to the release.

Kathryn Gifford, AETC’s rated diversity improvement program analyst, said RPP graduates have improved their Air Force Officer Qualifying Test and Test of Basic Aviation Skills scores by about 40 percent. Both tests are considered by rated selection boards.

“Of the 93 RPP students trained in fiscal years [2019 and 2020], 70 applied to the undergraduate flying training board, with 55 (78 percent) applicants selected for a rated position,” Gifford said.

Officers who want to attend RPP must meet the following requirements, according to the release:

“Be of high moral character”
Receive permission and endorsement from their group commander or a higher-level leader
Pass the Air Force physical fitness test
Receive their Pilot Candidate Selection Method initial scoring results prior to RPP, then agree to retake the AFOQT and TBAS two to four weeks after completing the course.
Have less than five hours of civilian flight time. (Those with more than five hours will be considered on a space-available basis only.)
Obtain the Air Force flight physical for the career field they are looking to cross-train into

Enlisted personnel must:

Be under 33 years old as of March 20, 2022
Earn a bachelor’s degree with at least a 2.5 grade point average
Agree to get your commission as soon as possible after completing RPP.

Editor’s Note: This story was corrected on Nov. 24 to note that officers with more than five hours of civilian flight time will be considered on a space-available basis.

Space Industry Experts Think DOD Can Help Spur More Private Investment

Nov. 22, 2021 | By Amanda Miller

Increased Pentagon spending on commercial space technology can prompt private investors to invest more, continuing record investment in the U.S. space sector, according 232 experts attending the State of the Space Industrial Base 2021 Workshop. They cited sustaining investors’ confidence as a “major concern” requiring “urgent action.”

The report “State of the Space Industrial Base 2021: Infrastructure and Services for Economic Growth and National Security,” written by five defense leaders, draws its conclusions from the working sessions of the workshop attendees.

Brought together by NewSpace New Mexico, the group’s goal was to advise on how to “nurture and grow a healthy space industrial base and national security innovation base.” The five authors—Space Force Brig. Gen. John M. Olson, mobilization assistant to the Chief of Space Operations; Space Force Col. Eric J. Felt, director of the Air Force Research Laboratory’s Space Vehicles Directorate; Joel B. Mozer, chief scientist of the Space Force’s Space Operations Command; Steven J. Butow, the Defense Innovation Unit’s space portfolio director; and Thomas Cooley, chief scientist in the Air Force Research Laboratory’s Space Vehicles Directorate—released the conclusions Nov 18.

The group also called on the Defense Department to more than double the share of its overall acquisition budget used to acquire commercial services, seeking an increase from “single digit percentages” to 20 percent.

The report summarizes the “collective voice” of all 232 experts, many of whom work for space companies. Other urgent concerns include “adequate resourcing to accelerate innovation” and “attention to brittle supply chains.” They also want DOD to provide vendors clearer “strategic guidance.”

U.S. space companies are “the subject of intense predation” of intellectual property by foreign investors, the report said. A mandate in the 2021 National Defense Authorization Act to report on space competition with China is “comprehensive,” but the White House should further consider these matters as part of strategic “supply chain planning.”

The report highlights “major opportunities,” such as the military’s interest in joint all-domain command and control (JADC2) as well as developments in cislunar space. Its recommendations include:

Spur investment beyond launch. Private investment in commercial space is concentrated in launch services, and participants say “too little capital [is] flowing into other verticals ready for investment.” The authors seek “defense and intelligence contracts significant enough to sustain current private investment levels” as necessary to “secure American leadership” in commercial space. Private investment in space infrastructure alone reached $4.5 billion in the second quarter of 2021, a record, but DOD could build on that and help attract even more private money for in-space servicing, mobility, and logistics firms.
Start building the cislunar ‘space superhighway.’ Transportation and communications infrastructures “are fundamental antecedents to much broader economic activity,” the report said. “Although the nation is contemplating a multi-trillion, once-in-a-generation infrastructure plan to ‘win the future,’ no part of it addresses the emerging in-space infrastructure or China’s desire to surpass the U.S. in building it.”
Adopt a hybrid military-civil architecture for JADC2. A hybrid architecture can “harness commercial capabilities … to enhance the resilience” of DOD’s satellite communications architecture, the report said.
Buy more commercial services. Policies, budget processes, and the “lack of procurement innovation incentives” stand in the way of “more agile and rapid innovation” across the DOD in “various technology valleys of death,” the authors said. Workshop participants judged that such a commitment “requires policy and incentives that drive toward a goal of 20 [percent] non-traditional commercial service acquisitions.”

‘The Clock Is Ticking’ as Ukraine Seeks Air Defense Aid

Nov. 22, 2021 | By Abraham Mahshie

With some 90,000 Russian troops massing on Ukraine’s eastern border and holding large-scale military exercises in the area, worries are growing that Russian President Vladimir Putin is preparing a possible invasion or other military actions against Ukraine. Ukrainian Minister of Defense Oleksii Reznikov visited Washington Nov. 18-19 seeking military assistance, but some fear a mismatch between the urgent situation and the slow pace of major international arms sales.

Russia’s joint exercises with Belarus included a presence northeast of Kyiv, which makes this situation different from prior mobilizations, including Russia’s 2014 invasion of southeastern Ukraine, said a senior Senate staffer, who asked not to be named. That southern region is still held by Russian-backed separatists, fueling a low-intensity conflict that persists in violation of the Minsk agreement that ended the invasion.

What’s different this time, the staffer said, is that in 2014, Putin “didn’t really use airpower because he was looking for some deniability.” This time, however, Putin has set up a different course of action. “If he goes this big, he’s not going to care about deniability,” the staffer said.

As winter approaches, the muddy fields, lakes, and rivers of Eastern Ukraine are freezing over, so mechanized vehicles and close air support left at the border after Russia’s exercises will have an easier route to travel.

To counter that, Ukraine will need counter-air, counter-artillery, and anti-tank weapons, said the staffer, who met with Reznikov during his recent visit to Washington.

“We did have a discussion about the counter-air,” the staffer said, but the minister seemed to be after “the Patriot-size stuff,” while short-term needs might be greater. “I would be worried about the next two months and getting everything we can that can make a difference,” the staffer said.

Getting approval to sell a complex air defense system such as the Patriot will take too long, he said, when the U.S. or NATO partners can offer man-portable air-defense systems such as the Stinger, which is still effective against slower-moving aircraft.

Marine Corps Lt. Col. Anton T. Semelroth, a Pentagon spokesperson, said in a written statement that U.S. assistance to Ukraine is ongoing. Investment reached $400 million this year and a total $2.5 billion since 2014. Another $300 million is anticipated in the 2022 National Defense Authorization bill, which is expected to clear the senate in early December.

“The United States has previously announced security assistance support in these domains,” Semelroth wrote, citing “air surveillance radars, counter-artillery radars, counter-unmanned aerial systems, and armed patrol boats.”

Asked by Air Force Magazine what systems he is seeking from the U.S., Reznikov said only that he sought air and naval defenses.

The Threat from Belarus

Close relations between Putin and Belarusian strongman Vicktor Lukashenko gives Russia a useful partner in the neighborhood. Belarus’ open invitation to Middle Eastern migrants to travel through it on tourist visas fueled a migrant a crisis earlier this month on the border with Poland involving tens of thousands of Polish and Lithuanian troops.

Wojciech Lorenz, defense analyst for the Polish Institute of International Affairs, said this was a new type of hybrid warfare and should be seen as a warning to Europe that it should cease assisting Ukraine.

Lorenz said Belarusian forces provoked Europeans on the border, using lasers to temporarily blind security patrols, firing stun grenades, and shooting blanks into the air. The psychological campaign seems designed to provoke a response which could then be used by Russia to suggest that NATO is planning to invade Belarus.

“We have seen major escalation,” Lorenz said in a phone interview from Warsaw. “By increasing the credibility of escalation against Poland, the Baltic States, and NATO through Belarus, they wanted to send a signal: ‘Stay away, because you will have military escalation on your borders, so do not offer any support to Ukraine.’”

Lorenz said Russia could be trying to press Ukraine to reenter negotiations and to seek autonomy for the breakaway states of Donetsk and Luhansk. “Of course, because [the two states] would be controlled by Russia, with their special status in this federalized Ukraine, they would just block any decision that is not in Russia’s interests,” Lorenz said.

Lithuanian military attaché Brig. Gen. Modestas Petrauskas does not believe the migrant crisis poses a military threat to Europe, but he told Air Force Magazine that it has the potential to destabilize the region.

“We are one of the most tense regions in the entire NATO [area of responsibility], the eastern flank,” he explained. “Anything which can have a potential of escalation or misunderstanding is sort of impacting the overall security situation.”

The Senate staffer likewise does not believe the Belarus migrant crisis is of military concern but said it does divert Ukraine’s attention from the Russian troops to its east.

“I don’t see that as a valid threat,” the staffer said. “What I do see is Belarus is a threat from the north to Ukraine and the pretext being used to put troops there.”

“The clock is ticking,” he said. “If we’re going to do something, that decision needs to be made and move out.”

US Has ‘a Lot of Catching Up to Do’ in Hypersonics, Space Force’s No. 2 Says

Nov. 22, 2021 | By Greg Hadley

One day after the Space Force’s second in command warned that the U.S. is “not as advanced as the Chinese or the Russians in terms of hypersonic programs,” a media report indicated that China’s likely test of a nuclear-capable hypersonic weapon this summer included an added capability.

Financial Times, citing anonymous sources familiar with the matter, reported Nov. 21 that in July, China launched a hypersonic glide vehicle into space, part of a suspected orbital bombardment system that now is said to have fired a missile while flying at least five times the speed of sound.

The ability to fire a projectile off a supersonic platform is “a capability no country has previously demonstrated,” Financial Times reported. The Wall Street Journal subsequently reported the news as well.

The Defense Department has yet to comment on the latest development, though Chairman of the Joint Chiefs of Staff Gen. Mark A. Milley and Vice Chairman Gen. John E. Hyten have both previously confirmed the nuclear-capable hypersonic test—Hyten said such a weapon looks like a “first-use” weapons in a nuclear scenario.

Space Force Gen. David D. Thompson, vice chief of space operations, spoke at the Halifax International Security Forum on Nov. 20, just before the latest reporting on the additional projectile. But when asked about the hypersonic test more broadly, he noted that the U.S. has “a lot of catching up to do very quickly.”

“The Chinese have had an incredibly aggressive hypersonic program for several years,” Thompson added. “And I agree with Gen. Hyten—it’s a very concerning development. I don’t know if it’s a first-use weapon. I will tell you, it greatly complicates the strategic warning problem.”

Thompson explained the challenges to the strategic warning system by likening the Chinese hypersonic missile to a “magic snowball.”

Ballistic missiles follow predictable trajectories, allowing defense systems to track them more easily. By comparison, a hypersonic missile “changes that game entirely,” Thompson said. Using the example of a snowball fight, he explained that with a hypersonic missile, “I can throw that snowball in this direction, I can throw it in that direction, I can throw it in this direction—and it will maneuver back and it’ll hit you. In fact, it might even fly by you, turn around, and hit you in the back of the head. That’s what a hypersonic glide vehicle does. Combine that with a fractional orbital bombardment system, and I’m going to throw the snowball that way, and it’s going to go around the world, and it’s going to come hit you in the back of the head.”

Such a capability makes the world a “much more complicated place,” Thompson said, especially as the Pentagon works to catch up.

Gillian Bussey, director of DOD’s Joint Hypersonics Transition Office, has said the Army will field the military’s first hypersonic weapon in a “year or two.”

Fighter Mission Capable Rates Fell in 2021

Nov. 22, 2021 | By John A. Tirpak

Mission capable rates dropped in 2021 for every Air Force fighter type except the A-10, reversing progress in 2020, according to data released to Air Force Magazine.

“Mission capable” rates are a common measure of readiness and relate to an aircraft’s ability to perform at least one of its core missions; for example, the multirole F-16 is tasked for air-to-air combat, ground attack, or suppression of enemy air defenses. By contrast, “full mission capable” refers to an aircraft that is ready to perform all of its assigned missions. Full mission capable rates were not provided.

The Air Force aims for MC rates between 75 percent and 80 percent on most aircraft, but none stood at that level as fiscal 2021 ended.

The declines are noteworthy even though the Air Force has sought to de-emphasize the rates and instead focus on unit readiness as a more accurate way to evaluate combat capability. Also noteworthy is that 2020’s gains were achieved at the height of the COVID-19 pandemic, when greater restrictions were placed on the physical proximity of workers in backshops and depots.

The F-35A rate declined from 76.07 percent to 68.8 percent from 2020 to 2021 as an increasing number of F-35s came due for their first big engine overhauls. A shortage of engines has grounded about 40 F-35As over the past year, a level that the F-35 Joint Program Office predicts could hold for several years.

Still, the F-35A mission capable rate remained above that of 2019, when it was just 61.6 percent.

With operating costs disappointingly high, the Air Force has throttled back on new F-35A purchases until the more capable Block 4 version is ready and operating costs can be brought down to a more sustainable level. Congress has gone along, with members recognizing that adding airframes has only exacerbated a shortage of parts and made it harder to achieve objective mission capable rates.

The next biggest drop struck the F-15E fleet, which saw MC rates fall three percentage points, from 69.21 percent in fiscal 2021 to 66.24 percent. The decline continued a trend; in fiscal 2019, the Eagle’s MC rate was 71.29 percent.

The F-15C and D rates also fell. The C model declined to 69.48 percent from 71.93 percent, and the D model fell from 70.52 percent to 68.56 percent. As with the E model, the C and D declines continued a trend dating to 2019, when rates were in the 70s. The Air Force’s F-15C fleet is beyond its planned service life, and the jet is encumbered with numerous operating restrictions and “vanishing vendor” parts shortages.

The F-16C and D fleet similarly shed percentage points: The C model turned in an MC rate of 71.53 percent in fiscal 2021, down from 73.9 percent in fiscal ’20. The D model came in at 69.32 percent, down from 72.11 percent. Both aircraft were above 70 percent in fiscal 2019.

The stealthy F-22 continued to hover at just over 50 percent, reflecting the fleet’s relatively small size and numerous challenges. The Air Force said the rate was just 50.81 percent in 2021, about one percentage point down from 2020, and just about equal to 2019, when it was at 50.57 percent. The Air Force has chalked up low F-22 MC rates in recent years to challenges caring for the jet’s low observable systems as well as continuing repercussions from severe damage inflicted on about 10 percent of the fleet by Hurricane Michael in 2018. Parts obsolescence is also an issue.

The venerable A-10s are the healthiest, if least capable, jets in the fighter force. Perhaps benefitting from an ongoing re-winging program, the A-10 MC rate ticked up from 71.2 percent in fiscal 2020 to 72.54 percent in fiscal 2021. The A-10 is generally less sophisticated than the other fighters, with fewer sensor systems, and its maintainers are generally more experienced, as most Warthogs belong to the Air National Guard and Air Force Reserve.

When Jim Mattis was Defense Secretary early in the Trump administration, he ordered the Air Force and Navy to raise MC rates for fighter aircraft to 80 percent. The Air Force never achieved that goal, saying at the time that MC rates were not a meaningful indicator of overall readiness for war. A frontline deployed unit typically is close to 100 percent mission capable because parts are prioritized for such units, while squadrons recently returned from deployments can see MC rates decline rapidly.

Editor’s note: This story was updated at 8:12 p.m. Nov. 22 with the correct F-15D rates.