Confirm the problem
Read the technical log, speak to the reporting crew when possible and check whether the condition is present now. A vague complaint should be clarified before troubleshooting begins.
Understand the system
Review the system purpose, normal configuration, interfaces and indication logic. A good mental model makes the approved troubleshooting path easier to follow.
Separate facts from assumptions
List confirmed indications, recent maintenance, environmental conditions and repeat history. Do not treat a familiar symptom as proof of the same cause.
Follow approved logic
Use the current applicable fault-isolation source. Perform tests in the required order and respect cautions, access requirements and configuration conditions.
Close the loop
Document the action, result and any deferred follow-up clearly. Good troubleshooting includes good communication.