Overview

• The watchdog reports Block 4 is at least $6 billion over prior estimates and will deliver fewer capabilities than originally planned.
• Lockheed delivered 110 aircraft in 2024 and all were late by an average of 238 days, with TR-3 cited as the primary cause.
• The Pentagon has accepted about 174 jets with TR-3 hardware but immature software for training use pending retrofit.
• GAO found incentive structures rewarded late performance, allowing fees on aircraft up to 60 days late, and urged DOD to reevaluate fees and contractor capacity.
• Parts shortages and engine delays continue to strain production, with more than 4,000 shortages and 52 jets pulled from the line, while engine and cooling upgrades now push post–Block 4 capabilities into the early 2030s and total lifecycle costs above $2 trillion.