In which scenario would a CAT 3 TPDR be necessary?

A Category 3 Technical Procedure Deviation Report (TPDR) is specifically designed for situations where the deviation from standard procedures does not pose a significant risk to safety or mission capability. This means that in the scenario where there is a minor situation and an acceptable workaround is available, a CAT 3 TPDR is appropriate. The existence of a workaround indicates that the operation can continue without critical delays or serious safety implications, which aligns perfectly with the definition and use of CAT 3 reports.

In contrast, situations characterized by major safety risks, critical technical malfunctions, or significant operational impacts would necessitate higher-category reports, as they would not meet the criteria of being minor or acceptable without immediate corrective action. Therefore, the context of having a minor issue with an established workaround justifies why a CAT 3 TPDR is necessary in that scenario.