EMB ERJ 190/195 ER/LR
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 20500
Confusion
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Inflight Event / Encounter Other / Unknown
Flight Crew Returned To Departure Airport; General Maintenance Action; General Declared Emergency; General Flight Cancelled / Delayed
Procedure; Human Factors; Aircraft
RNAV departure; pitch trimmed airplane 'Up'; tried to engage autopilot at 1;000 feet MSL. Autopilot would not engage. Retrimmed pitch 'Up' again; Elevator Trim went to full down. Declared emergency. First Officer (FO) ran QRH for Pitch Trim runaway. Airplane accelerated to 265 knots; disengaged autothrottles; returned to field landed on Runway 17 L. Captain's Pitch Trim [switch on yoke] was wired backwards. [Recommend] better Quality Control; safety inspector.
Reporter stated flight crews were not required to check the Pitch Trim on the Control column during preflight or aircraft swaps; only the Back-Up Switch and Cutout switches were checked on the Center pedestal. The First Officer (FO) normally sets up the pitch trim during their preflight check. The previous day; a different Captain noted the Pitch Trim on the EMB190 did not work and they swapped aircraft. The EMB190 remained overnight. The next day; he and the FO were scheduled on that same EMB190; but there were no previous Log pages to indicate what work had been accomplished on the Pitch Trim System or Maintenance History available. His First Officer flew the first leg with no problems. The next flight was his and shortly after liftoff; when he tried to retrim the Pitch 'Up'; the Pitch Trim went to 'Full Down'.Reporter stated the EMB190 is an all 'fly-by-wire' aircraft. No physical control cables connect to the Horizontal Stabilizer from the cockpit. No Horiz Stab Manual Trim wheel on the side of the Center pedestal. When the event happened; he and the FO both started operating the Pitch Trim switch on each Control yoke. What they did not know was the Captain's Pitch Trim switch on the Captain's yoke overrides the First Officer's Trim switch input when operated at the same time; which is exactly what they were doing. A later discussion with their Senior Check Airman/Trainer; confirmed that the Captain's Pitch Trim switch will override the FOs switch. Had they known that; they would have tried operating the switches separately. Reporter stated he had wrapped both forearms around his Control column and pulled with at least 90 to 100 pounds of backpressure to overcome the pitch down attitude of the EMB190. He was not sure at that moment if they would regain pitch control. His Air Carrier issued a Flight Bulletin requiring all Flight crews to check operation of their (Manual) Pitch Trim switches on the Control yokes at originating flight of the day or; when swapping aircraft. Maintenance indicated Captain's Pitch Trim switch had been wired backwards during reinstallation of the switch; apparently when the aircraft stayed overnight. He was wondering if the wires were color-coded and if so; could a Technician that was color blind have incorrectly connected the switch wires? Does Maintenance require an Inspector to also check the installation on the switch?
Log page XXXX7. Pitch Trim Switch-2 fail on EICAS. Accomplished Fault Isolation Manual (FIM) for the Horizontal Stab (HS) System; all checks good; but four messages were shown on EICAS: 1) Pilot Pitch Trim switch fail. 2) Copilot Pitch Trim switch fail. 3) Back-up Pitch Trim switch fail. 4) Flt Control No Dispatch.Some other troubleshooting directed by Maintenance Control was accomplished. The last one was; the Return to Service Test; with the pilot's Pitch Trim switch disconnected. This test also passed. And Maintenance Control directed us (Mechanics X and Y) to replace the pilot's Pitch Trim switch. It was replaced per Aircraft Maintenance Manual (AMM) 27-43-02. Operational Test of the HS System successful; per AMM 27-40-00-710. The original Horizontal Stabilizer Actuator Control Electronics (HS-ACE) was reinstalled per AMM 27-43-01. I; Mechanic X; performed Operational Test of the Flight Control System successful per AMM 27-00-00-710. And no message on EICAS. According to the pilot [report]; the aircraft flew from ZZZ to ZZZ1; from ZZZ1 to ZZZ2 and then after takeoff from ZZZ2; the autopilot disconnected; Pitch Trim went 'Full' down; Pedestal Trim went inoperative; QRH was followed. Pilot Pitch Trim switch Removed and Replaced (RR) per AMM 27-43-02. An Operational Test performed good per AMM 27-40-00. HS-ACE computer replaced per AMM 27-43-01. Operational Test good per AMM 27-00-00.Instructions from the manual must be followed.
A Captain describes his efforts to regain control of an EMB190 aircraft during initial climb when the aircraft suddenly pitched 'Full Down' after he had attempted to retrim Pitch 'Up'; using the Manual Pitch Trim switch on his Control column. Aircraft had accelerated to 265 knots. Emergency declared. Two mechanics also report their involvement with replacement of the Captain's Pitch Trim switch that was later found installed backwards.