F-35A vs F-15K: Why the Newest Stealth Fighter Faces More Parts Swaps?

Translation resultParts shortfalls for the F-35A — a core air-defense asset that South Korea’s Air Force has operated for only seven years — have led to a severe cannibalization problem, with technicians regularly stripping parts from one jet to install in another.On April 18, the office of People Power Party lawmaker Kang Sun-young, a member of the National Assembly’s Defense Committee, released an analysis of Air Force data titled “Status of Cannibalization by Fighter Type Over the Past Five Years.” The report found roughly 420 cannibalization incidents involving South Korea’s F-35As from 2021 through April 2026.Incidents surged last year and are trending upward, prompting concern inside and outside the military. Annual per-aircraft cannibalization rates and the corresponding incident counts cited in the report are: 2021 — 1.1 per aircraft (40 × 1.2 = 48 cases); 2022 — 0.6 (39 × 0.6 = 23.4); 2023 — 2.4 (39 × 2.4 = 93.6); 2024 — 1.8 (39 × 1.8 = 70.2); 2025 — 3.5 (39 × 3.5 = 136.5); and through April 2026 — 1.2 (39 × 1.2 = 46.8). Converted to annual case numbers, that totals 418.5 incidents over five years.Cannibalization refers to taking an identical part from a grounded aircraft of the same type and installing it on a flight-ready jet. Put simply: if Aircraft A suffers a fault and spares are scarce or supplier deliveries are delayed, crews take the same part from Aircraft B to return A to service.The Air Force purchased 40 F-35As beginning in 2019 and currently operates 39; one was retired in January 2022 after an expensive repair following a bird strike. Observers say it is notable that the F-35A — a modern stealth fighter in service only seven years — has been cannibalized about three times more often than the older F-15K, which has been in service for nearly two decades. That disparity has raised questions about the F-35A’s mechanical characteristics, maintenance practices, or parts-supply system.Rep. Kang warned, “To deter North Korea’s advancing nuclear and missile threats, modern fighters like the F-35 must be kept at constant high readiness. Cannibalization may be a stopgap response to parts shortages, but it undermines Air Force operations. A fundamental solution is urgently needed.”An Air Force official pushed back, saying, “The F-35A contains 200,000 to 300,000 parts. When an unexpected failure occurs, sourcing replacements can take a long time. Until we secure replacement parts, we must cannibalize identical parts from aircraft already under maintenance to maintain acceptable readiness rates.”Another key platform, the F-15K — procured beginning in 2005 and currently fielding 59 aircraft — logged roughly 340 cannibalization incidents over the past five years. Reported annual per-aircraft rates were: 2021 — 0.4 (59 × 0.4 = 23.6); 2022 — 0.8 (59 × 0.8 = 47.2); 2023 — 0.6 (59 × 0.6 = 35.4); 2024 — 1.2 (59 × 1.2 = 70.8); 2025 — 1.9 (59 × 1.9 = 112.1); and through April 2026 — 0.9 (59 × 1.2 = 56.1). That sums to about 345.2 incidents over five years.Compared side by side, the F-35A shows roughly 70 more cannibalization incidents than the older F-15K, despite the F-15K’s longer service life — a gap that underscores concerns about the F-35A’s sustainment situation.The Air Force’s most numerous fighter, the (K)F-16 (about 160 aircraft), recorded roughly 1,050 cannibalization cases over the past five years — the highest total of any type. The domestically produced FA-50 light attack jet logged about 340 incidents in the same period. The oldest fighter in the fleet, the F-5 light fighter, and the KA-1, which performs light attack and tactical control duties, each recorded about 70 cannibalization cases.Even high-end ISR platforms are affected. The Global Hawk (RQ-4), four of which were acquired beginning in December 2019 to bolster surveillance and reconnaissance — a capability tied to the transfer of wartime operational control — also reportedly undergoes frequent cannibalization because replacement parts are difficult to obtain.Responding to criticism that newer aircraft are being cannibalized more often than older types, the Air Force said that cannibalization is practiced by other air forces, including the U.S. Air Force, and that Seoul limits the practice under the authority of approving officials to preserve acceptable operating rates.