Date: 201708
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 100
Light: Daylight
Aircraft: Sail Plane
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Climb
Aircraft component: Aileron Control System
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Human Factors

Narrative: Club owned training glider received disassembly and greasing of wing/control connections as part of normal maintenance by a group of pilots and club members. Aircraft was reassembled; positive control check was executed; and the aircraft was put back in service by the pilot in charge of the maintenance. I flew the aircraft on the following day. I did a normal preflight inspection and positive control check with a student prior to our flights; and found the aircraft to be airworthy. We executed two flights with no problems with the front seat/student pilot on the controls. On our third flight during aero tow; the student informed me that something seemed wrong with the controls - he was having to hold slight right aileron to stay wings level. The tow aircraft then flew a 270 degree left turn to keep us within our designated glider tow area. After completion of that turn; both glider and tow plane were wings level where we were able to assess that the aircraft left aileron was either coming disconnected; or partially disconnected - both ailerons were slightly (1/2 inch) above the wing trailing edge while we were holding right stick pressure. At that point; I radioed our tow pilot and informed him that we may be in the process of an emergency; and to slowly descend from our current altitude with the glider in tow. Following the radio call; I asked for the controls of the aircraft for the remainder of the flight. While descending on tow; the tow plane made a left turn to keep us within the glider box; and put us on a heading towards the airport. During this time; I assessed the maneuverability of the aircraft with the left aileron appearing to be partially connected. I decided that if nothing changed with the controls; that the aircraft was controllable and we would be able to fly a pattern to a landing. I again radioed our tow pilot and requested that he fly us in position to enter a crosswind entry into [the] pattern. I planned and set up a high crosswind entry and wide pattern so that we could fly shallow turns using only the slightest control inputs. I was able to fly this pattern to a normal landing and roll out. During the roll out the glider went over a bump in the asphalt; and I heard our left aileron disconnect. I checked visually; and saw that it had drooped and that stick inputs didn't move it. The right aileron remained positively connected. We rolled to a stop in control and on the runway centerline. Pilot in charge of maintenance ops was instructing students on glider assembly process allowing the students to make hotelier control connections on their own inside of the inspection port. Hotelier connectors may have been improperly assembled during instruction and not cross checked. No test flight was done after assembly. My student and I were both aware that the aircraft had been disassembled and reassembled the previous day; but did normal preflight checks and positive control check without visually checking the control hookups in the inspection port. As the person responsible for the safety of the flight; I was deficient in my duties as PIC by both not visually checking that the control connections were properly assembled; and by deeming the aircraft airworthy without this inspection. Personally; I am visually and physically checking hotelier connects on all preflight inspections. The club that owns the glider is in the process of discussing corrective actions and changes in operations related to both maintenance actions carried out by club pilots on club aircraft; and communications within the club glider pool. Corrections in procedures when maintenance is carried out; as well as how testing occurs and documentation completed when aircraft are put back into service post maintenance are being considered.




Synopsis: ASK 21 glider instructor pilot reported landing safely after noticing the left aileron had become partially disconnected from the control linkage apparently due to improper maintenance.