SR 3-5396507207
2022年8月，机队运行中连续两架飞机反应在尾撬余水口发现螺钉。
打开狗洞和尾撬的盖板，并未发现丢失，且该规范号并为在该区域找到适用。
波音表示非常少用到，可能与结构修理相关。
The screw found in B-17X5 looks similar to BACS12CK type screw. This screw has few installations in section 48. Boeing notes that BACS12CK screws are installed at the STA 1016 cable seal installation. See AIPC 27-41-00-11.
The bolt found on B-57X5 looks to be a typical structural permanent fastener, but the head marking does not reveal any possible source.
Boeing appreciates HNA completed inspection of tail skid zone and tail compartment. Boeing recommends reviewing recent maintenance or repairs in section 48 that would include part and fastener removals. Boeing recommends another inspection verification of systems installations for missing screws and structure installations, including brackets, for missing permanent fasteners.