MD-80 Series (DC-9-80) Undifferentiated or Other Model
Maintenance Powerplant; Maintenance Airframe
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
General Maintenance Action
Procedure; Human Factors; Aircraft
Aircraft X; on approach to ZZZ had following PIREP: on approach the rudder travel unrestricted light did not illuminate until 140 kts. Per MM 27-20-00 Page block 101. Rudder and Tab-Troubleshooting. 1. Troubleshooting A.F.Steps 1-5. The Rudder Travel Unrestricted Warning Light should have come ON at or before 191 kts. It did not illuminate until 140 kts. The Contract Maintenance Employee only accomplished step 3 in the troubleshooting guide. Contract Employee's signoff: Accomplished bite check of both rudder proximity switches...inspected rudder throw limiter proximity sensor brackets...cleaned debris from sensors. This contract employee's actions are covered under step 3 in the troubleshooting guide; and all was found to be OK. Employee DID NOT DO ANY MORE TROUBLESHOOTING to determine why the rudder travel did not become unrestricted until 140 knots. If the Pilot Flying had to execute an evasive maneuver; i.e. possible bird strike; windshear; go-around; auto-pilot disconnect; weather event; evasive action to prevent mid-air collision; etc.... The aircraft's rudder movement was limited; thereby restricting its movement and the subsequent full-authority control of the aircraft. The ZZZ employee should have done more troubleshooting to determine why the discrepancy occurred. Rudder not rigged properly. Rudder Limiter System; Excessive Friction. Pitot tube sump clogged. Throw-Limiter actuator and linkage out of adjustment. The employee only accomplished a sensor check - Step 3- and returned the aircraft to service. The problem repeated on another flight. Cause: Inadequate experience level; troubleshooting skills; MD-80 familiarity; unfamiliar with Maintenance Manuals. Suggestions: Follow Maintenance Manual Procedures as defined by company policy and CFR's.
MD-80 Maintenance Technician reported that Contract Maintenance did not complete the Rudder Travel Unrestricted Warning Light troubleshooting procedure.