Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 410; Flight Crew Type 9350
Troubleshooting
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem
Aircraft
While approaching ZZZ at approximately 3000 feet we reported the field in sight and were cleared the visual to XXL by Approach Control. I set up the MCP to capture final using LNAV and VNAV and set 1500 feet in the altitude window. The autopilot didn't seem to be capturing the magenta glide path symbol; and the ILS GS (Glideslope) diamond showed us slightly high on GS; so I decided to click off the autopilot and capture the GS and Localizer manually. Localizer was selected on the MCP and I started down the GS. I needed approximately 20 degrees of bank to intercept the Localizer. As I turned the control wheel; I noticed a definite binding in the ailerons anytime I went beyond 15 or 20 percent of wheel throw (eventually turning in both directions to align the aircraft). In retrospect; the controls felt very similar to the forces required during the use of control wheel steering. I mentioned to the FO (First Officer) that the ailerons felt weird and a little stiff; but completely controllable; so we continued. Once established on final; and while making only small corrections with the control wheel; the control wheel felt completely normal. The aircraft remained completely controllable at all times with normal aileron feel as we approached the runway. The landing was uneventful. Once at the gate; Dispatch; Maintenance Control; Chief Pilot; and local Maintenance were notified; and logbook entries were made. The aircraft was taken out of service for inspection and repair.This report is being filed in the interest of safety because it involves an unknown flight control abnormality; or possible operator error unknown at the time of occurrence.
B737-700 Captain reported aileron stiffness while hand flying an approach.