What indicates a properly repaired engine blade?

A properly repaired engine blade is marked with blue or red metal ink to indicate that it has gone through the necessary inspection and meets the required standards for airworthiness after being repaired. This marking serves as an important visual cue that communicates to maintenance personnel that specific repair procedures were followed and that the blade is safe to use.

The use of colored ink, such as blue or red, is a standardized practice in aviation maintenance to easily identify which components have been inspected or repaired. This practice helps ensure that only components meeting safety and performance criteria are reinstalled on aircraft, facilitating better tracking and accountability in maintenance practices.

In contrast, the other characteristics mentioned, such as having a jagged edge, showing heavy wear and tear, or having visible cracks, would typically indicate damage or inadequate maintenance. These conditions would render an engine blade unfit for use and signify that it requires further inspection or replacement rather than validation as a properly repaired part.