FAA Powerplant Written Practice Test

How should terminal lugs be installed to prevent movement in the direction of loosening?

1. With a removable design

2. By locking them against movement

3. With additional adhesive

4. In a flexible manner

The correct answer is: By locking them against movement

The installation of terminal lugs is critical to ensure a reliable electrical connection, and one of the primary considerations is preventing movement that can lead to loosening over time. Locking terminal lugs against movement serves the dual purpose of maintaining connection integrity and preventing wear and tear caused by vibration and thermal expansion variations. When terminal lugs are securely locked in place, they are less likely to experience the micro-movements that can cause loosening. This is often achieved through various methods, such as using locking features on the lug design, appropriate torque specifications during installation, and sometimes employing mechanical locking mechanisms or lock washers. These techniques ensure that the lugs do not shift or rotate in their mounted position, thus maintaining a stable electrical connection. In contrast, other methods such as using a removable design or applying additional adhesive may not provide the same long-term stability and may lead to challenges during maintenance or replacement. Additionally, a flexible installation is not advisable in this context, as flexibility can lead to movement and subsequent loosening.