Is there hope for a program's future if it is not in the sacred Top Three priorities of the U.S. Air Force—the F-35 Joint Strike Fighter, the KC-46 aerial refueler and the long-range bomber?

For months, the USAF's message has been tightly controlled. Keep those three programs moving forward; anything else is subject to cuts or, if it is a new start, indefinite deferral. But Gen. Mark Welsh, Air Force chief of staff, revealed a peek into his priorities beyond the dramatic sequestration cuts that have derailed military spending plans in recent months.

Aside from his Top Three, Welsh says he would like to start projects to replace the aging E-8C ground-surveillance and T-38 fast-jet trainer fleets. Industry is already prepared for both—with primes and subs pairing off to pursue these projects. But first, Congress must provide a funding profile that will support them, Welsh notes.

Thus, the Air Force is developing two potential budgets—“high” and “low” proposals. The latter takes into account a worst-case scenario of sequestration impacts stretching through fiscal 2015. The former allows for at least some new-start work, though not as much as the service had hoped.

The E-8C Joint Stars fleet is housed on aging Boeing 707 airframes, all of which were purchased as used platforms before being modified with mission systems in the 1990s and 2000s. So, their service life is hampered and maintenance cost is high. That, coupled with a desire from combatant commanders for more and better ground surveillance—tracking ground vehicles to individuals on foot—is behind the need. An analysis of alternatives conducted by the service has pointed to a solid business case for housing the next system on a business jet to access both its speed and low operating cost. And significant advances have been made in active, electronically scanned array radars to allow for multimode detection and tracking of many targets simultaneously.

The E-8Cs are housed on the oldest of the USAF's 707s, but it is likely that the service could embark on a larger recapitalization project to eventually put the E-3 Airborne Warning and Control System air surveillance and RC-135 Rivet Joint signals intelligence missions on the same business jet platform.

Industry teams are ready for the T-X program to buy 350 T-38 replacements; the Air Force has slipped the competition, delaying fielding until at least 2023. BAE Systems/Northrop Grumman with the Hawk T2, General Dynamics/Alenia Aermacchi with the M346, and Lockheed Martin/Korea Aerospace Industries with the T-50 are all competing. Boeing, said to be in talks with Saab for a partnership, is eyeing a brand-new design. Gen. Edward Rice, head of the Air Education and Training Center, says he cannot recommend a quick start to T-X in this budget environment because the T-38 is still safe to fly.

Up for cuts are several mainstay Air Force programs. The service is pursuing as many “vertical” cuts, or wholesale fleet terminations, as possible, because the savings are more profound than simply slicing a portion of a fleet. With a vertical cut, the service divorces itself from the cost not only of the aircraft, but also of an entire training and supply chain.

Potential vertical cuts include the A-10 fleet and MC-12W Project Liberties. Both conduct niche missions. “If funding weren't an issue I would love to have that capability, [but] there are other things I need more desperately than the MC-12,” says Gen. Mike Hostage, who heads Air Combat Command. The L-3 Communications MC-12Ws were just fielded in 2009 to satisfy an urgent need for more intelligence collectors in Iraq and Afghanistan.

A-10s, by contrast, have been lauded for decades by the Army for their precise close air support (CAS). The Air Force has tried before to kill the A-10 fleet during budget crunches, but Army officials often convince Congress to keep them. Hostage says that with targeting pods and precision-guided munitions, CAS can be had through a variety of platforms. “While they were not happy, [Army leaders] understand we are in a fiscal crisis,” he says. “I am not backing away from the mission. I am just adjusting the way I'm doing it.”

Several other fleets are facing partial cuts. These include the Lockheed Martin C-130 and General Atomics MQ-9 Reaper unmanned aircraft. “We are trying to convince [the Office of the Secretary of Defense] that the 65 [combat air patrol] challenge . . . is not the force structure the nation needs or can afford,” Hostage says. “Predators and Reapers are useless in a contested . . . environment [and] I need anti-access capability.” Hostage did not reveal what the right number of Reapers would be.

Likewise, the service may shed old, excess C-130s, even while proposing another multi-year deal of the new “J-model” of the tactical transports. Presently, the Air Force has approximately 340 C-130s, but USAF Gen. Paul Selva, head of Air Mobility Command, says the requirement is closer to 300.

Selva is also proposing an early retirement to the KC-10 refueler fleet. It could retire early as the Boeing KC-46 comes onboard. The KC-10 provides more refueling capacity than the KC-135 and was once uniquely capable of providing fuel to Navy and Marine Corps jets that use the probe and drogue receiver interface. Now, however, the service has outfitted the majority of its KC-135s into the R configuration, which allows for the workhorse tanker to conduct such missions.

The topline requirement for tankers is 479 aircraft, so it is possible the USAF could reduce the KC-10 fleet as early as the first 18 KC-46s are introduced into service in 2017.

Also up for a reduction is the C-5A fleet. C-5As have notoriously low reliability; by contrast, the C-5M—which includes new engines through a Lockheed Martin program—has proved to be highly reliable. Congressional members have held retirement plans for the fleet at bay in hopes of protecting missions at their home-state Air Force bases.

Selva says the C-5M, a modernization that includes new engines for the strategic airlifter, is highly reliable and, as such, is not being eyed for a cut. Likewise, the C-17 fleet appears safe.

Budget drills are likely to examine other possible cuts until the final proposal is delivered to Congress early next year.

See how U.S. Air Force programs are faring amid budget uncertainty and other factors at AviationWeek.com/afa2013