More than 200 of the Air Force’s most expensive and important aircraft were briefly grounded in February after it was discovered that the pins that hold the vertical stabilizer to the fuselages of most Air Force variants of the Boeing 707 were substandard. The five-inch pins are potentially a single point of failure since one of them bears 90 percent of the stress of keeping the tail on. KC-135 tankers along with highly specialized RC-135 and WC-135 surveillance planes were affected. The E-3 Sentry AWACS and E-8 JSTAR aircraft were not affected.
According to a Facebook post on an unofficial group for Air Force maintenance personnel, the pins are replaced every time the planes go for heavy maintenance. Between June of 2020 and December of 2022 pins made by a specific supplier were determined to have been made of the wrong material, were too small, weren’t plated properly and hadn’t been shot peened, which is necessary to strengthen them. There have been no mishaps so far and the inspection only takes 30 minutes. So far, about 25 faulty pins have been found.
