Date: 201207
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: EMB ERJ 190/195 ER/LR
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Horizontal Stabilizer Trim
Component problem: Design; Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Confusion; Situational Awareness; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Aircraft; Chart Or Publication; Human Factors; Manuals
Primary problem: Human Factors

Narrative: July 2012. On Aircraft X; an ERJ-190 aircraft; I removed and replaced the Captain's Pitch-Trim switch in accordance with Aircraft Maintenance Manual (AMM).  Did a Return to Service and Operational Test per AMM.  Operational Check good; MEL was cleared. Two days later; Pilot in ZZZ1 reported Captain's yoke Elevator Trim (Pitch Trim) switch operates opposite to input. In ZZZ1; Captain's [Pitch] Trim switch was re-installed per AMM and Operational Check good; OK for service.

Callback: Reporter stated that on the ERJ-190 aircraft; when replacing the Pitch Trim switch on the Captain's or First Officer's Control Yoke; the switch and the electrical wires to the switch are removed as one unit. The wire harness is disconnected from a Canon plug type connector at the bottom of the Yoke through an access plate and harness wires are pulled-up through the Yoke column and out through the yoke thumb switch position.  On older EMB-145's that were not modified to the Canon plug type electrical connector; the wires at the bottom of the Yoke for the Pitch Trim switch had to be soldered in place; when replacing the switch assembly.   Reporter stated that after he changed the Pitch Trim switch; Maintenance received a call from the Flight crew at the gate; just prior to pushback; that the Pitch Trim switch on the Captain's yoke was inoperative. He changed the Horizontal Stabilizer Actuator-Control Electronics (HS-ACE) unit; that did not help; so the switch was placed on MEL again and the aircraft departed. He was later told that a Line Mechanic in ZZZ1; noted the Captain's Pitch Trim switch had been installed in reversed; or upside down. He doesn't believe he actually did that; since he and an Inspector had to perform an Operational Check and visually verify the Horizontal Stab moved in the correct direction prior to clearing the original MEL deferral. The ERJ-190 Maintenance Manual does warn that the Pitch Trim switch can be installed incorrectly.  He believes the EMB-140/145 aircraft had a keynotch on the switch that would prevent; or at least make more difficult; an incorrect switch installation; but the ERJ-190 does not.



Synopsis: A Line Mechanic was informed that a Captain's Pitch Trim switch he had previously replaced on an ERJ-190 aircraft was found installed backwards; after a Pilot reported the Pitch Trim operated opposite to input.