Date: 201505
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Flight phase: Parked
Aircraft component: Aileron
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Maintenance Action
Contributing factors: Human Factors; Incorrect / Not Installed / Unavailable Part; Procedure
Primary problem: Human Factors

Narrative: First Officer (FO) reported to me that on preflight walk around that he saw what appeared to be aircraft skin delamitation occurring on the back side/top of both wings. We called for a Mechanic who met us plane side.  He retrieved a maintenance lift truck and he and I went up to look at the wing. There was a rubber seal under the back of the outboard aileron that had curled laterally.  It was present on both wings at the same aileron location. We discussed it and I asked him if an Airframe/Powerplant (A/P) Mechanic could take a look at it. He stated that he was an A/P. He speculated that it may be caused by wing bending due to fuel load in the wings and thought it may subside once the fuel had been used. He stated that he would go to the Maintenance office and confer with other mechanics.  About 15 or 20 minutes later he returned to the cockpit and stated that he had discussed it with five other mechanics and a few of them had gone up on the lift to inspect the wing. According to the Mechanic I was working with; all six of them agreed and their consensus was that is was probably caused by too much painting over on the rubber seal that caused it to curl; but it would not propose a problem to fly the airplane. I discussed it with my FO and the Mechanic and we concluded that it was not a safety of flight issue and that flying the airplane to ZZZ1 would be fine.  The Mechanic did advise that we write it up once we arrived in ZZZ1 to get it into the Maintenance log for future repair scheduling. We departed for ZZZ1 and prior to landing sent a maintenance request write-up to ZZZ1 Maintenance to give them a heads up. At the gate in ZZZ1; I spoke with the Mechanic who met our flight and briefed him on what had taken place. He stated that he had seen this issue all the time and I took that as to mean it was not a problem. A few hours later I learned from the Captain scheduled to fly the airplane back to ZZZ; that the airplane had been taken out of service because the rubber seals had been installed backwards. Preflight checklist conducted on the flight controls in the cockpit indicated free and clear movement of the ailerons. We had no issues flying the airplane and it handled normally in all phases of flight.




Synopsis: Captain was informed that the B757 aircraft he had just flown was taken out of service due to rubber seals at Left and Right ailerons were installed backwards and curling laterally. Conditions of the seals were noted by himself and Maintenance at the previous departure station; but were not considered to be a safety of flight issue.