F-35 Proves Nuke Drop Performance in Stockpile Flight Testing

November 20, 2025

Two B61-12 joint test assemblies loaded on an F-35 aircraft for a flight test on Aug. 19. (Image: Craig Fritz)

Sandia, in conjunction with the National Nuclear Security Administration (NNSA), conducted a series of recent stockpile flight tests at Tonopah Test Range in Nevada, with support and aircraft generation from Hill Air Force Base in Utah.

The tests, conducted Aug. 19-21, yielded positive results as inert units of the B61-12 nuclear gravity bomb were successfully carried and dropped by an F-35, marking a significant milestone in evaluating the weapon’s performance. In late 2024, NNSA completed a multiyear life extension program for the B61-12, extending the bomb’s service life by at least 20 years.

A Sandia technologist keeps a watchful eye prior to loading a B61-12 joint test assembly into an F-35 aircraft for thermal conditioning tests. (Image: Craig Fritz)

The August tests were the only B61-12 stockpile flight tests of joint test assemblies on an F-35 aircraft, solidifying the end-to-end reliability of the aircraft, crews and weapon system during missions.

However, that was not the only significant first during these tests. The series also included the first-ever thermal preconditioning of a joint test assembly for carriage on an F-35 aircraft prior to its release, validating B61-12 environmental requirements in a real-world combined environment. Stockpile flight tests support the NNSA laboratories’ annual assessments and exercise warfighter capabilities.

An F-35 aircraft, loaded with a B61-12 joint test assembly, departs from Hill Air Force Base. (Image: Craig Fritz)

“These B61-12 F-35A stockpile flight tests and captive carry flight test were the capstone accomplishment of a tremendous amount of planning and effort by those who were involved across not only Sandia, but many other agencies,” said Sandia’s Jeffrey Boyd, Surveillance Lead for the B61-12 and B61-13. “In addition, these B61-12 stockpile flight tests represent the completion of the most B61-12 flight testing surveillance scope in a year to date and the most in a given year for the foreseeable future.”

A B61-12 joint test assembly lands at Tonopah Test Range on Aug. 20. (Image: Tonopah Test Range Team)

Tonopah Test Range Manager Brian Adkins, who oversaw the tests at the range, said test days always require adapting a test plan with adjustments necessary to safely execute the test. “Expedient coordination by the entire test team resulted in two successful days of testing to evaluate three test assets,” he said.

Collaboration between Sandia stockpile systems, the operational test staff at Tonopah Test Range and the U.S. Air Force enhances operational evaluation of the F-35 aircraft’s reliability and accuracy for various missions. As data from these tests is analyzed, it will yield critical insights that support Sandia’s mission to advance the frontiers of science and technology and contribute to national security efforts at the Labs.

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