A report released by the U.S. Government Accountability Office (GAO) and analyzed by Business Insider on 16/6 reveals that both the KC-135 refueling aircraft and the newer KC-46A Pegasus model have failed to meet mission capability and operational readiness standards for financial years 2019-2025.

The GAO stated that the U.S. Air Force has identified operational sustainment risks for its refueling fleet but has not yet conducted a comprehensive assessment or developed a plan to mitigate these issues. These risks include "shortages of critical repair parts, personnel for aircraft maintenance, and infrastructure limitations".

U.S. KC-135 aircraft conducting a refueling mission in the Middle East in 12/2025. Video: USAF

Specific figures on annual mission capability rates and readiness levels were not disclosed, as the Pentagon believes these statistics are too sensitive to be made public.

The U.S. military has heavily utilized its refueling aircraft fleet over the past year, from the strikes on Iranian nuclear facilities in 6/2025, the raid on Caracas to apprehend Venezuelan President Nicolas Maduro in 1/2026, to the outbreak of conflict in the Middle East in late 2/2026.

Aerial refueling capability is crucial for long-range offensive operations. The U.S. refueling fleet must maintain an almost continuous airborne presence to provide timely fuel to forces engaged in missions.

During the strikes on Iranian nuclear facilities last year, six U.S. F-16 pilots reported returning to base with "extremely low" fuel after encountering refueling issues early in their mission.

Open-source statistics indicate that the U.S. lost at least 7 KC-135 refueling aircraft during six weeks of conflict with Iran, including one that crashed due to a mid-air collision with another aircraft over Iraq, resulting in the deaths of six service members.

U.S. KC-135 refueling aircraft taking off from a base in the Middle East in 4/2026. Photo: USAF

The U.S. Air Force tracks readiness indicators and mission capable rates. However, these indicators lack sufficient detail to determine if an aircraft can perform its most critical role: providing logistics support to fellow aircraft.

A refueling aircraft is considered mission capable if it can perform at least one assigned task, though not necessarily refueling other aircraft.

Military experts have previously expressed concern about the readiness of the U.S. refueling fleet. John Venable, a retired U.S. pilot and expert at the Mitchell Institute for Aerospace Studies, believes the Air Force would struggle to provide support for a large-scale operation given the current condition of its refueling aircraft.

Pham Giang (According to Business Insider)