Date: 201301
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
ATC / advisory: Ramp ZZZ
Aircraft component: Wing Access Panel
Component problem: Failed; Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Human factors: Situational Awareness
Second reporter function: First Officer
Anomaly: Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Pre-flight
Result: Aircraft Aircraft Damaged; General Maintenance Action
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: I was Captain. We reported to the aircraft at the usual time. As is typically done; the First Officer conducted the external preflight while I began cockpit checks and setup. Nothing unusual was observed on the preflight. We conducted a normal flight; where the First Officer did a post flight; and we left the aircraft. I had no idea that anything was unusual until our Chief Pilot called me two months later. Apparently; an inspection panel on top of the wing was left unsecured by Maintenance personnel during their work the night before. At some point between the time this maintenance mistake was made and two legs after we completed our flight; the unsecured panel came off and went into the engine; causing engine damage. We had no indication of anything amiss. The First Officer found nothing wrong on his preflight; and we had no anomalies during flight. The First Officer conducted a post flight inspection; where he found no discrepancies. Nothing was found until two additional flights were conducted by a different crew. Maintenance released the aircraft with an unsecured panel. Whatever systems and procedures our mechanics follow didn't catch the error. Any person can make mistakes; but the system should be able to catch things like this. Clearly this didn't happen. Due to the location of the panel; it is very hard to see on a normal pilot preflight. If the panel was in its normal position but not screwed in; it would be even harder to detect. I know that my First Officer is very conscientious and would have done a good preflight. The takeaway from all this is a reminder to do things the proper way; and be thorough. And be prepared for anything; since many errors and discrepancies can escape even a thorough preflight.


Second narrative: I performed my pre-flight walkaround of the aircraft like normal in accordance with airlines procedures and did not notice anything unusual. However; I have since learned that the maintenance access panels located on the top of the wing over the main gear were not properly affixed by Maintenance during the preceding night's maintenance inspection even though the aircraft had been signed off for return to service. I am told that at some point the panels separated from the wing surface and one of those panels was then ingested by the Number 2 Engine. We did not receive any unusual engine indications during our flight and I did not notice anything unusual during the post-flight walkaround either. The aircraft was handed off to another flight crew at our first destination and they then completed a round-trip before noticing that the panels were missing.I believe that it was extremely difficult to notice that these panels were not properly affixed for several reasons: First; this particular panel is above or almost above eye level and hard to see. Second; the screws that secure the panel are normally flush with the surface making it hard to notice when they are missing. Lastly; during this point in the inspection the pilot's attention is normally primarily devoted to the status of the main gear which is located directly below this panel on the underside of the wing. It is my opinion that it is unrealistic to expect the pilot to examine every screw on an aircraft of this size and complexity. In the future I will pay closer attention to these particular panels during my walkaround inspection but it will still be very difficult to see whether or not all of the screws are installed and secured properly.


Synopsis: A CRJ-900 crew reported that two upper wing service panels were missing; one of each wing; after an overnight landing gear pivot point service. The crew flew the initial flight after the service but were notified long after about the event.