Date: 202008
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe
Contributing factors: Human Factors; Aircraft
Primary problem: Aircraft

Narrative: As I prepared for departure of Aircraft X; I inquired about the lack of a [Maintenance Release]. I was told the a Ramp Service Employee had reported a cotter pin missing on a NLG (Nose Landing Gear) door and maintenance was investigating. Curious as to what cotter pin a ramp service employee would be looking at and why; I went down to the nose wheel well to see. It seems that the aft Nose gear doors on Aircraft X each have an adjustable proximity stop on their forward ends. This stop consists of a length adjustable bolt that is held in it's adjusted position by a metal clip or pin. That pin was missing on the right door adjusting bolt which allowed it to spin freely; varying its length. Upon examining the left bolt; it struck me as something not very likely to become dislodged. I would like to believe that if the clip was an item that required frequent examination; it would have been pointed out during walk around training. It was not. We did have the part at ZZZ; but the maintenance manual called for a gear swing to confirm nose gear door alignment. As a result; Aircraft X was taken out of service. A replacement aircraft was brought down from the hangar. While the Tech Ops employees were preparing Aircraft Y for departure they expressed their extreme frustration that this particular ramp service employee was 'constantly' touching things that were not part of his job and finding aircraft faults that were not within his purview. They went on to say that this ramp employee had been caught in the cockpit manipulating switches. When confronted he stated that he had seen it on YouTube and wanted to see for his self. I took my First Officer's down to the nose wheel well of Aircraft X to show them where the fault had been found. All of them reported that they were unaware of the stop limit bolts and none had been trained to inspect them. As we stood there; three Ramp Servicemen happily approached; two of them pointing at the third who identified himself as the person who had found the faulty bolt on the other aircraft. The person that found the faulty bolt explained to me that he 'liked to touch those bolts after in plugged in his cord'. I did not ask why and I resisted the urge to ask him not to touch parts of the equipment that were not his responsibility. I know that we are on a very slippery slope when we ask someone not to report faults. However; I am concerned and uncomfortable to learn that an employee with no technical training is examining my aircraft in search of mechanical faults. I'd like to think that the retaining clip had departed the aircraft on it's own volition and the ramp serviceman was so proud of himself because he had found a problem; but; given the anecdotal information supplied by the Tech Ops and CS employees about our recent performance at ZZZ; I am left to wonder.As an aside; as part of the preparation for our flight; Tech Ops had to run both engines to get an accurate quantity check. Just before pushback I was asked to run the left engine again because this same ramp serviceman thought he saw an oil leak. Net result 3:19 late out 2:44 late in and [next flight was] 2:01 late out and 1:35 late in.




Synopsis: Air carrier flight crew reported a missing aircraft part was discovered by ramp agent and resulted in a flight delay.