Date: 201310
Local time of day: 1201-1800
Location: STP.Airport, MN
Light: Daylight
Aircraft: No Aircraft
Reporter organization: Corporate
Reporter function: Other / Unknown
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine; Maintenance Apprentice; Maintenance Powerplant
Human factors: Confusion; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Airport; Human Factors
Primary problem: Airport

Narrative: This is a vehicle ground movement report. I returned with my fellow crewmember to the FBO in a rental car. Our aircraft had been placed in hangar storage the evening prior for possible inclement weather. We were not certain of hangar location; and asked lineman at the FBO for assistance; as we had baggage to load in the aircraft and pre-flight duties to complete. We were advised we could drive our car to hangar (not visible from our current location) by 'driving around the adjacent hangar.'We observed surface markings that indicated a taxiway to traverse to get there; but markings were inconsistent with ground vehicle markings on FAA website; there was nothing to indicate a movement/non-movement area border; and no signage to indicate any requirement to contact ATC for permission. There was also no road that we otherwise could have taken to get from the ramp area at the FBO to the storage hangar where our aircraft was located. The combination of these factors and the lineman's direction to drive around the adjacent hangar gave us no reason to believe this would create any concern. Since it was mid-afternoon; we had a clear view of the airfield; so we were able to determine that there were no active aircraft nearby. We proceeded a short distance on Taxiway 'W' from the FBO (located off large NW ramp area adjacent to southwest end of 'L') to the storage hangar immediately south. Shortly after arriving at the hangar (by car) a representative of MN Aero Commission arrived and advised of our driving across an active taxiway without prior permission. He stepped out and returned shortly to advise of a request to contact the tower; which I did. Tower Supervisor asked general questions on behalf of airport; took my name and phone number.Later that afternoon prior to departure I was advised to contact the Airport Manager the next day; which I did. He explained their review process for these incidents; using the phrase 'incursion' at one point; and asked questions related to my situation. I again explained the instructions we were given to drive to the hangar; non-standard markings; no signage indicating a need to call Tower and the fact that there was no separate road to get from the FBO to the hangar. He asked if I had seen a 'path' through a grassy area next to the taxiway; which he said was normally used by vehicles. I advised that although I had seen a path; given the soft appearance of the path from the rain the night before; it never occurred to me that this 'path' was the route that should have been followed to the storage hangar. The Airport Manager indicated similar events have taken place at STP in the past; and agreed with me that they did have some non-standard markings and needed to improve signage to prevent similar future occurrences.It should be noted that my fellow crewmember and I have over 65 years of flying experience and have been at many airports without ever having this type of problem because the ground markings and/or signage were clear. Based on my experience and training and the combination of circumstances; there was no reason to believe our actions were not appropriate or unauthorized.




Synopsis: Corporate flight crew is advised after the fact that that they have incurred on Taxiway W at STP while driving a vehicle to their hanger. There were no ramp markings indicating the non movement area boundary and the crew was not aware of dirt path normally taken by vehicles to avoid Taxiway W.