What is the proper check for TGB and IGB cap security?

The proper check for TGB (Tail Gearbox) and IGB (Intermediate Gearbox) cap security involves ensuring that the caps are properly secured to prevent any leaks or failures during operation. The correct amount of finger clearance, specifically 3-4 fingers, allows for a safe and effective assessment of the cap's tightness. This range indicates that the cap is neither too loose, which could present a risk, nor too tight, which might make it difficult to check or remove during maintenance.

Using this 3-4 finger guideline ensures that there is a balance between security and accessibility. It reflects training best practices that have been established based on engineering standards and maintenance regulations. When conducting this check, it's essential to maintain the integrity of the gearbox system, as any compromise could lead to high-stakes issues like fluid leaks or failures, impacting the safety and performance of the aircraft.