The Government Accountability Office published report GAO-26-109154 on June 10, 2026, finding that the Air Force's two primary aerial refueling tankers — the KC-135 Stratotanker and the KC-46A Pegasus — both failed to meet their availability and mission-capable-rate goals in every fiscal year from FY2019 through FY2025, a six-year consecutive streak of missed targets driven by chronic parts shortages, an underdeveloped maintenance workforce, and unresolved engineering deficiencies on the KC-46A.
Six Years of Missed Readiness Targets
The KC-135 Stratotanker, the backbone of the tanker fleet, recorded a mission-capable rate of just under 68 percent in fiscal year 2024. The newer KC-46A Pegasus fared worse, posting a 62 percent mission-capable rate for the same period. Both figures fell short of the Air Force's stated readiness goals, continuing a pattern the GAO documented across six fiscal years. The report, titled "Aerial Refueling Tankers: Air Force Needs More Focused Metrics and a Risk-Based Mitigation Plan to Improve Sustainment," is one of the most pointed assessments of tanker readiness the oversight body has issued in recent years.
Parts shortages are the primary driver of degraded readiness on both platforms. On the KC-135, some replacement components are no longer in production, forcing maintainers to rely on cannibalization, secondary markets, or time-consuming fabrication alternatives. On the KC-46A, the GAO found higher-than-expected part failure rates tied to military modifications applied to the commercial Boeing 767 airframe, modifications that introduced stress and failure patterns the commercial 767 design was not originally engineered to absorb.
The readiness picture is further complicated by a measurement blind spot the GAO identified in current Air Force metrics. The existing mission-capable-rate framework does not specifically assess whether an aircraft can perform its primary refueling mission. A tanker categorized as not fully mission capable may still retain the ability to offload fuel — meaning the reported rates may understate or mismeasure the fleet's actual refueling availability in any given period. GAO recommended the Air Force implement metrics that specifically capture refueling mission capability and require regular reporting on those metrics to leadership.
KC-46 Engineering Deficiencies Persist
The KC-46A has carried a list of unresolved deficiencies since its initial delivery, but two hardware issues remain central to contractor and Air Force planning. The Remote Vision System — the camera-and-display assembly that boom operators use to guide the refueling boom — has required a full redesign. The RVS 2.0 upgrade, intended to correct image distortion and depth-perception problems that created safety concerns during contact operations, was previously scheduled for fielding in summer 2027. That timeline has slipped again; the GAO found the current projection for RVS 2.0 fielding is now early 2028.
A second hardware fix involves the boom telescoping actuator, which became stiff during operations and has been redesigned. The actuator issue affects the mechanical reliability of the boom itself — the primary fuel transfer interface between the tanker and receiver aircraft. Both represent continuing obligations for Boeing as the prime contractor and for the Air Force's KC-46 program office.
Workforce readiness compounds the hardware problems. At some Air Force bases, approximately 75 percent of tanker maintainers lack the experience levels necessary to fully support the aircraft they are assigned to maintain. That figure, drawn from the GAO's fieldwork, reflects both the overall pace of personnel turnover in the maintenance career fields and the added complexity of sustaining a platform still working through engineering corrections.
What It Means for Contractors
The GAO's four recommendations, all concurred with by the Department of the Air Force, create a direct compliance and business development roadmap for industry participants in the tanker sustainment ecosystem.
- Metrics and reporting requirements: The Air Force must implement metrics that specifically measure refueling mission capability and report on them regularly. Contractors holding performance-based logistics or availability contracts tied to mission-capable rates should expect contract language to evolve as the Air Force redefines how it measures readiness. Any recompete or modification on KC-135 or KC-46 sustainment vehicles should be tracked closely for updated performance thresholds.
- Risk assessment and mitigation planning: GAO directed the Air Force to conduct a service-wide comprehensive risk assessment of tanker sustainment and develop a risk-based mitigation strategy. For prime contractors and their supply chains, this is a signal that the Air Force will be mapping supply risk at the component level — creating potential task order opportunities for DLA-linked parts procurement, diminishing manufacturing source programs, and alternative sourcing studies for obsolete KC-135 components no longer in production.
- KC-46 production modifications: The higher-than-expected failure rates on militarized KC-46 components indicate the Air Force and Boeing will face additional engineering change proposals in the near term. Suppliers to the KC-46 program with parts affected by military modification loads should anticipate qualification testing requirements and potential contract modifications as failure data matures.
- Workforce development: The 75 percent inexperience figure at some bases is a policy gap that has historically opened doors for contractor logistics support and contractor maintenance augmentation task orders. Firms with Air Force maintenance training contracts or base operating support vehicles should monitor the Air Force's response to this finding as it develops its mitigation strategy.
- RVS 2.0 and boom actuator contracts: The revised 2028 fielding date for RVS 2.0 extends the period of Boeing's corrective action obligation and continues to affect the KC-46's operational ceiling. Suppliers and subcontractors in the RVS and boom actuation supply chains should be aware that schedule pressure on the 2028 target will intensify over the next 18 months.
The Air Force's concurrence with all four GAO recommendations is noteworthy because it carries an implicit commitment to respond with corrective action plans within an established timeframe. GAO will track implementation and report on progress in future high-risk and defense readiness assessments. Contractors whose program offices interact directly with the tanker program — Air Force Materiel Command, Air Mobility Command, and the KC-46 System Program Office at Tinker Air Force Base — should expect increased reporting cadence on sustainment performance beginning in fiscal year 2026.
The broader readiness picture for aerial refueling capacity matters to nearly every major Air Force and joint operational plan. Tanker availability determines strike range, ISR persistence, and airlift throughput across all combatant commands. A fleet that has missed its readiness targets for six straight years represents both a sustained operational risk and a sustained market signal: sustainment investment in this portfolio is not discretionary.
