ACC’s New Readiness Metric
By Matthew Cox
AURORA, Colo.
When Air Combat Command began developing a simplified aircraft readiness metric two years ago, the aim was to turn voluminous data points into a single number that could enable commands at every echelon to know exactly how many planes they could get off the ground on any given day.
Now, with Gen. Kenneth S. Wilsbach, the former ACC commander, as Air Force Chief of Staff, that system is spreading to other major commands.
Readiness Informed Metrics, or RIM, goes beyond mission capable rates and other averages to focus instead on how much airpower a unit can generate. ACC’s endorsement now has Air Mobility Command adopting the concept as well.
Ask any commander to explain readiness measurements and the answer is usually “complex.” Mission capable rates are one of the best known metrics: Aircraft are deemed mission capable when they are able to perform at least one of their core missions, such as counterair, electronic warfare, ground attack, and data collection, as in the case of an F-35A Lightning II. In 2024, the mission capable rate for F-35As was 51.5 percent. But rates are averages, and don’t speak to what units can do at a specific moment in time. So a squadron deployed for combat operations can show a 90 percent MC rate in theater, when its parts needs are prioritized, and fall well below 50 percent when it returns and is no longer at the front of the line. The Air Force stopped publicly releasing mission capable rates after 2024.
Break rates and fix rates—the percentage of aircraft requiring maintenance before they can be made mission capable, and the time required to make those repairs—are additional measures used by commanders to understand fleet readiness. While this provides more granular detail, these closely guarded numbers are also averages.
RIM boils all that down to a single number that tells if a unit can generate its assigned airpower requirements or, if not, how short of the goal it is. Squadron numbers can be rolled up into wings, wings into Numbered Air Forces, NAFs into a majcom, providing leaders at each level a way to understand their organization’s readiness in comparison to their requirements.
RIM also arms higher-level commanders to more easily communicate risk to headquarters, combatant commands, and the Joint Staff and could potentially be used as a transparent means of communicating readiness to Congress in terms of resource needs, said Brig. Gen. Brian S. Laidlaw in one of the most detailed explanations of RIM to date.
“We still track fixed rates; we still track break rates; we still track how long it takes to get the jets back—all of those numbers are still valid,” Laidlaw told Airmen at AFA’s 2026 Warfare Symposium in February. “They are foundational to what we do, but we need to pick one [number] that we can rally around, that’ll help us tell the story, that will align the enterprise.”
RIM settles on “mission capable airplanes—something that we could see, something that we could touch, something that we can communicate across the enterprise and say, ‘this is the minimum number of mission capable airplanes that we need,’” Laidlaw added. “That’s the key to getting ready, since that became our North Star.”
Laidlaw’s comments align with Wilsbach’s emphasis on readiness—to “fly and fix to fight and win our nation’s wars,” as he has said since becoming chief in November.
Air Force fighter, bomber, tanker, and other crews have been operating at a high tempo for the past year, beginning with Operation Rough Rider against the Houthis in Yemen, and following through with the Midnight Hammer raid on Iran’s nuclear infrastructure last June, Absolute Resolve against Venezuela in January, and since Feb. 28, Operation Epic Fury against Iran.
Compared to the 1980s, today’s Air Force operates with smaller squadrons and wings, each with fewer mission capable aircraft than in earlier generations. During the Cold War, each fighter wing had three squadrons of 24 fighters, and mission capable rates averaged 80 percent. When a wing deployed, it sent two squadrons, each fully manned and with 24 mission capable aircraft, leaving behind the third wing which donated jets and crew to ensure the deployed squadrons were fully ready.
Today, fighter wings have just two squadrons, typically fewer than 24 aircraft each, and mission capable rates are just 60 percent or less. Deployed units send just 12 aircraft forward in a typical deployment, notes John Venable, a senior fellow at the Mitchell Institute for Aerospace Studies and a retired Air Force colonel.
Laidlaw recalled flying as a young officer in F-15C Eagle squadrons with 24 jets in the early 2000s. “When we did our phase one and our phase two exercises, if you didn’t generate 24 aircraft during your exercise, someone was going to have to answer to that—that was the bar,” Laidlaw said. “Over time, we haven’t necessarily been able to do that.”
Before implementing RIM, ACC officials analyzed years of readiness data, finding that mission-capable rates slowly degraded over time. Said Laidlaw: “What we saw when we looked at this was, over time, [how] we defined success was largely based on the previous year’s performance.” The net effect was that “year after year, you see [USAF] setting the goal post lower and lower.”
With RIM, however, “we tie [readiness] directly to a mission, directly to a requirement,” Laidlaw said. “Everyone can see that it’s a whole number. Either I have the number of airplanes that I need to do what I’ve been tasked to do, or I do not have the number of airplanes I need to do my tasking.”
That delivers a level of clarity that isn’t there when leaders juggle percentages. Laidlaw would not provide specific RIM data, noting those figures are classified. But he did offer a hypothetical: a wing commander with 200 assigned aircraft and a RIM requirement of 150. “You know that you have to have 150 mission capable aircraft every day,” Laidlaw said.
“When you show up at work in the morning and you look out the window and you look across the flight line, and there’s only 100 airplanes out there that are mission capable,” this much is clear: “We’re 50 airplanes short.”
Unlike other measures, which may look different depending on where in the wing you sit, RIM is the same for everyone: “It doesn’t matter if you’re wearing pilot wings, if you’re wearing a maintenance badge, if you are from any one of the support agencies that are absolutely critical to building those mission capable rates, you get it immediately. … It’s simplicity.”
What RIM also does is clarify the picture for senior commanders, Laidlaw said. ACC Gen. Adrian L. Spain chairs a video teleconference with ACC’s wing commanders twice a month, and senior leaders from operations and sustainment also listen in.
“Each wing commander puts up there one slide front and center, prominent, large, and he or she gets to answer the question: Am I meeting my RIM, or am I not meeting my RIM number?” Laidlaw said. “It is clear as day. Everybody gets to see it up and down the chain of command.”
Each commander is allowed three “detractors” that are keeping them from meeting the RIM target. When, at a recent meeting, one commander had an “abnormally high depot rate,” it was clear the issue is not under his control.
“We’ve got to modernize to generate readiness for the future,” Laidlaw said. “Well, that decision was made, in some cases, months, even years ago, by different commanders.”
That’s where Spain, as the overall commander, can step in and say, “Here’s my risk decision. We’re going to prioritize this and this,” Laidlaw added. “Everyone up and down the chain sees it … and now we go and we execute.”
Brig. Gen. Derek M. Salmi, director of operations for strategic deterrence and nuclear integration at Air Mobility Command said AMC is now working to incorporate RIM into its processes, while tailoring the concept to the mobility mission.
“We recognize the value of RIM as a very powerful … view of what the requirement is,” Salmi said, adding that the command has “spent a lot of time ensuring that our North Star number is correct, so we are shooting for the right target.”
Like ACC, AMC has incorporated RIM into its regular commanders updates.
“Every week, our maintenance professionals pick one of our major bucket systems, and we deep dive into it using the North Star number,” Salmi said. The process is “aligning everyone to what the clear target is, what levers we’re trying to pull all the way down to the wing level—to include more resources, more personnel, more equipment. So we’re aligned and not working at cross-purposes.”
While it remains unclear if RIM will be adopted in all the majcoms, under Wilsbach’s leadership, the service has begun to use similar concepts as he ramps up the focus on readiness. In early February, Lt. Gen. Kenyon K. Bell, deputy chief of staff for logistics, engineering, and force protection, said at the Mitchell Institute for Aerospace Studies’ Airpower Forum that his command is using a new framework, the “Air Craft Readiness Machine (ACRM),” to identify a North Star for tracking the availability of each aircraft in the USAF fleet as a means for prioritizing resources.
Pilot Readiness
RIM and ACRM are all about airplanes. What neither addresses is the people factors that squadron and wing commanders must watch, such as how frequently their people are flying.
Squadron commanders, whose focus is on their unit, rather than across a wing or majcom, find it difficult to separate materiel readiness—how many jets they can put on the ramp—and overall readiness—how many pilots can fly those jets off the ramp for real-life missions.
Air Force Lt. Col. Ryan Stillwell, a former B-1B Lancer squadron commander, said the two are intimately intertwined. Readiness assessments “should be based on how many sorties I need a month to keep my aircrew current and ready,” he argued.
To Stillwell, currently an education fellow at Mitchell, if the only goal is to maximize the number of mission capable jets, “you’d barely ever fly,” he said. “You would fix them and put them in a hangar, almost like a classic car. But that’s in conflict with why we have to fly these airplanes: The whole point of higher MC rates, or in this case, number of MC aircraft, is to be able to fly them.”
Another former B-1B squadron commander was similarly skeptical. Units track aircraft maintenance levels and crew flying hours very closely and that classified report “is pushed every month right from the squadron level and is reviewed by the majcom commander,” the former officer said. “But I’ll be completely frank with you: I personally never saw it drive any change at my level in the unit. … Something actually has to happen … to drive change.”
Multiple former commanders said the reality is that squadrons will take on missions regardless because squadrons will “always find a way to get it done,” one said. You don’t go into anything intending to fail or to not give it your best effort, despite the constrained resources. You’re still going to find a way to do it.”
That said, former commanders acknowledged RIM can help higher-level leaders, including civilians lacking in knowledge about detailed maintenance statistics, get a clearer picture of how many combat assets units can generate.
“This isn’t a panacea that will fix all the readiness problems,” Stillwell said. But RIM can provide a “more consistent way to report the true state of the force … that everybody can understand, whether it’s within the Air Force, or within a command from the Pentagon, all the way up to Congress.”