EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; General Maintenance Action
Aircraft
After starting both engines; flight control check was initiated; during aileron travel check to the left; resistance was felt in the yoke around 40 degrees of travel; and I had to force it the last 5-10 degrees to the stop; full deflection was noted left on the MFD. During the right aileron check; travel to the stop was normal; however inboard spoilers did not show fully deployed on the MFD. I had the First Officer check the aileron travel with his yoke; the travel was normal from stop to stop in both directions with no resistance to the left; and with full deflection noted in both directions. I called Dispatch and had them connect me with Maintenance. After talking with Maintenance we returned to the gate. During checks with Maintenance back at the gate my First Officer verified visually that the spoilers on the right-hand wing were not coming up fully during operation of the Captain's yoke during full right-hand travel as compared to the full left deflection. Back at the gate it was interesting to note that after the hydraulics were turned off; and no pressure in the system the resistance prior to the stop in the left aileron travel of the Captain's yoke was still there. My concern is that with no hydraulic pressure on the systems the problem was still there; and with the hydraulics on the First Officer wheel travel from aileron stop to stop was normal with full deflection indications.
EMB170 Captain reports an unsatisfactory aileron check after starting both engines using the Captain's yoke; but the check is satisfactory using the First Officer's yoke. Flight returns to the gate for maintenance; where the flight control anomalies are confirmed visually.