Aircraft mission capable rates, explained

A mission capable (MC) rate is the share of time an aircraft can fly and perform at least one of its missions. That is the Government Accountability Office (GAO) definition in GAO-23-106217, a November 10, 2022 report on 49 military aircraft. The Army also tracks a stricter status, fully mission capable (FMC), meaning able to perform all assigned missions. AR 700-138, the Army logistics readiness regulation dated April 23, 2018, sets goals for manned aircraft of 75 percent FMC and 80 percent MC. GAO found that the CH-47F Chinook met its MC goal in none of fiscal years (FY) 2011 through 2021.

The Army's status categories

AR 700-138 is the current edition and supersedes the edition of February 26, 2004. The regulation calls aviation weapon system readiness the primary mission of all aviation maintenance and logistics personnel. Paragraph 3-1 defines the statuses:

• FMC. The aircraft has the minimum required subsystems and equipment listed in the regulation's table 3-2, all completely functioning and capable of all assigned Department of the Army missions.
• Partially mission capable (PMC). The aircraft can perform only a limited number of missions or is limited in performing them.
• Not mission capable (NMC). The aircraft fails the table 3-2 minimums. All NMC time is either maintenance (NMCM) or supply (NMCS).

NMCM time covers troubleshooting, waiting shop, repair, and final inspection. NMCS time starts when a requested part is not available and stops when maintainers receive it. Table 3-2 lists equipment such as the attitude indicator and radar altimeter, and a note requires the Autonomous Flight Control System (AFCS), as the regulation names it, and both vertical gyros to be operative on the CH-47 and UH-60. A subsystem that is down adds PMC time, while a grounding condition adds NMC time. Units report monthly, from the 16th of one month to the 15th of the next, with a commander's statement for each aircraft that misses Army goals.

Goals and readiness levels

AR 700-138 table 3-1 sets the worldwide manned aircraft goals: FMC 75 percent, MC 80, PMC 5, NMCS 10, and NMCM 10. Ground and missile equipment carry a 90 percent FMC goal and unmanned aircraft 80 percent. The regulation ties the 75 percent aircraft figure to readiness level R-1 under AR 220-1, the unit status reporting regulation dated August 16, 2022. AR 220-1 table 5-3 rates aircraft at R-1 from 75 to 100 percent FMC, R-2 from 60 to 74, R-3 from 50 to 59, and R-4 below 50.

Public numbers are scarce for a reason. AR 700-138 designates equipment availability rates, including MC, FMC, NMCM, and NMCS, as Unclassified/For Official Use Only. GAO-23-106217 states that it is the public version of a September 2022 report that the Defense Department (DOD) deemed partly Controlled Unclassified Information, so it omits the rates themselves. GAO reports how many years each aircraft met its goal instead, and does not discuss FMC rates.

What GAO found in 2020 and 2022

The 2022 report found that only four of 49 aircraft met their MC goal in a majority of FY2011 through 2021, and 26 met it in no year. The Army's AH-64D/E, CH-47F, and UH/HH-60 each scored 0 of 11. GAO also found that the average MC rate for the selected Army aircraft had risen over the period, while the Air Force, Navy, and Marine Corps averages fell.

The CH-47F profile counts 417 aircraft and 58,125 flying hours in FY2020 and an average age of 8.7 years in FY2021. Program officials told GAO that a revised scheduled maintenance plan began in June 2019, moving heavy inspections from 200 and 400 flying hours to 320 and 640. Officials expected a 2.5 percent cut in scheduled downtime and a similar rise in MC rate, with the whole fleet on the plan by July 2022. Officials linked a recent rise in NMCM to fleet induction into that plan, short full-time maintainer staffing in Army National Guard units, and a shift from contractor to active-duty maintenance. On supply, they named low-demand parts such as airframe components and outer skins.

The earlier GAO-21-101SP, from November 2020, scored the CH-47 at 0 of 9 years for FY2011 through 2019. That report said the MC share rose as CH-47Fs replaced CH-47Ds, which needed more unscheduled maintenance, and that the D model retired in 2018.

Later GAO updates

GAO has carried the series forward in testimony. GAO-25-108104, dated March 12, 2025, reports that DOD missed FY2024 MC goals for 42 of 45 aircraft. The CH-47F missed its goal in every year from FY2015 through FY2024. Citing program officials, GAO attributes the maintainer shortage to Army National Guard units without enough full-time maintainers.

GAO-26-108888, dated March 4, 2026, draws on ongoing work. For FY2024 it counts only Army and Air Force aircraft, and 25 of 27 missed their goals. The CH-47F again missed its goal in every year from FY2015 through FY2024, but this testimony names depot maintainer shortages. The Navy and Marine Corps shifted toward counting mission capable aircraft, so GAO could not score them against annual goals after FY2021 and FY2022. GAO said it planned to report on that aircraft sustainment work in summer 2026.

What to check

• Does a readiness claim use MC or FMC? GAO's public reports use MC; the Army's 75 percent goal and AR 220-1 levels use FMC.
• Which GAO report and period does a figure cite: FY2011 through 2019, FY2011 through 2021, or FY2015 through FY2024?
• Is an aircraft-level rate in a public document? AR 700-138 designates availability rates Unclassified/For Official Use Only, and GAO omitted them.
• Does a CH-47F maintainer-shortage claim say whether it means Guard full-time maintainers (2025 testimony) or depot maintainers (2026 testimony)?
• Does a maintenance plan reflect the 320 and 640 flying-hour inspections GAO described, or the earlier 200 and 400?

Azcuna's ELLMENT for the CH-47 puts the Chinook's public technical manuals, the Army sling-load manuals and a unit's own SOPs on a laptop or tablet that answers a repairer's or flight engineer's question with no network and cites the manual and page. Azcuna submitted it as a concept white paper to the Army's xTech|Search 10 competition in October 2026.

Sources

1. 1AR 700-138, Army Logistics Readiness and Sustainability · Headquarters, Department of the Army (April 23, 2018)
2. 2AR 220-1, Army Unit Status Reporting and Force Registration - Consolidated Policies · Headquarters, Department of the Army (August 16, 2022)
3. 3Weapon System Sustainment: Aircraft Mission Capable Rates Generally Did Not Meet Goals and Cost of Sustaining Selected Weapon Systems Varied Widely (GAO-21-101SP) · U.S. Government Accountability Office (November 2020)
4. 4Weapon System Sustainment: Aircraft Mission Capable Goals Were Generally Not Met and Sustainment Costs Varied by Aircraft (GAO-23-106217) · U.S. Government Accountability Office (November 10, 2022)
5. 5Military Readiness: Implementing GAO's Recommendations Can Help DOD Address Persistent Challenges across Air, Sea, Ground, and Space Domains (GAO-25-108104) · U.S. Government Accountability Office (March 12, 2025)
6. 6Military Readiness: DOD Should Take Further Actions to Address Challenges Across the Air, Sea, Ground, and Space Domains (GAO-26-108888) · U.S. Government Accountability Office (March 4, 2026)

Where this shows up in our work

• ELLMENT for the CH-47 Chinook answers a repairer's or flight engineer's question from the Chinook's manuals and the Army sling-load manuals and cites the page, with no network.
• TRACE, the offline S1000D and IETM viewer opens S1000D, MIL-STD-3001 and PDF technical manuals on a tablet with every marking intact.