The Ministry of Defence has warned that F-35 availability will fall in the short term as it works through a backlog of corrosion-related maintenance, according to a letter from Permanent Secretary Jeremy Pocklington to the Public Accounts Committee.
Pocklington’s letter, dated 30 April 2026, describes corrosion worsened by maritime exposure as a growing concern that “impacts the availability of aircraft and will need constant management throughout the life of the programme.” While acknowledging the issue affects all F-35 nations, the letter states that “as maintenance activities intensify a short-term reduction is expected to clear the backlog.”
The MoD says it is addressing the problem through enhanced corrosion awareness and preventative practices at front line squadrons, deeper inspections conducted with UK and US industry partners, the development of more corrosion-resistant solutions within the wider F-35 programme, and by pushing the F-35 Joint Programme Office and industry to create what the letter describes as “rapid, agile and coordinated responses to corrosion occurrences.”
The admission of a forthcoming availability reduction is notable given that the PAC’s October 2025 report already found F-35 availability to be below both UK and global programme targets. The corrosion problem was exacerbated during Operation HIGHMAST, the carrier strike group deployment to the Middle East, with the letter noting that prolonged maritime deployment worsened corrosion issues and increased post-deployment recovery time. Those lessons have since informed planning for subsequent detachments including the early 2026 Cyprus deployment.
Corrosion is a challenge for carrier-based aviation more broadly, with salt air and humidity accelerating degradation of airframe components and coatings. For a stealth aircraft like the F-35, whose radar-absorbent surface treatments are critical to its low-observable characteristics, corrosion management carries operational as well as maintenance implications.
Wow. I thought availability was already low, now this on top.
Did older types like the Phantom, Bucc, Sea Harrier and SH FA2 have similar issues or is it a stealth coating RAM thing?