Springs.pdf

Inspection and Testing Inspection Requirements Inspection and testing of springs are carried out according to the maintenance manual for the major assembly to which the spring belongs. Springs are inspected for: Blueing, which indicates overheating Pitting caused by corrosion Compression strength Fr...

Inspection and Testing Inspection Requirements Inspection and testing of springs are carried out according to the maintenance manual for the major assembly to which the spring belongs. Springs are inspected for: Blueing, which indicates overheating Pitting caused by corrosion Compression strength Free length Distortion. Free length - Measure the length of the spring in the relaxed position 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 402 of 498 Testing Methods The compression strength of a spring is measured with a spring tester. The spring is compressed to a specified height, and the force required to do so is measured to ensure it is within tolerance. Valve spring tester Another check which may be performed is spring free length. This check measures the length of the spring in the relaxed position against a straight edge to ensure it is not buckled or distorted. Spring distortion affects the control the spring exercises over a mechanism. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 403 of 498 Spring free length and distortion testing examples Always replace a spring with the correctly identified part. In some systems, a range of springs may be available; these could be identified by a coloured paint mark to indicate their particular range. Correctly operated and maintained, a spring can be expected to have a long life; however, its operating environment and the nature of its task exposes it to the risk of failure. The following list summarises some of the risks: Any nick or scratch concentrates stress and leads to a fracture. Overheating can change the heat treatment and temper of the spring steel. This causes loss of tension/compression or fatigue failure. Corrosion in an environment exposed to the atmosphere or corrosive elements leads to surface deterioration and adds to stress or fatigue failure. The nature of spring steel makes it vulnerable to corrosion, and protective surface treatments are easily damaged. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 404 of 498