How many characteristics must be inspected in lockbolt fastener installations to ensure compliance with engineering specifications?

In lockbolt fastener installations, there are typically five critical characteristics that must be inspected to ensure compliance with engineering specifications. These characteristics ensure that the fastener is installed correctly and will perform as intended under operational conditions.

The five characteristics generally include things like the condition of the fastener (to ensure it's not damaged), the correct installation technique, the proper alignment of the fastener in relation to the materials being joined, the correct length of the fastener for the materials being connected, and the proper torque or tension applied during installation. Each of these factors is crucial in maintaining the joint integrity and overall performance of the assembly.

Inspection of these five characteristics helps to confirm that the installation meets the required safety and performance standards as outlined by engineering specifications, which is particularly important in aerospace applications where reliability is paramount.