Date: 201307
Local time of day: 1801-2400
Location: EAU.Airport, WI
Flight conditions: VMC
Light: Night
Aircraft: Super King Air 200
Operator: Air Taxi
Operating under: Part 135
Flight plan: None
Mission: Passenger
Flight phase: Taxi
ATC / advisory: CTAF EAU
Reporter organization: Air Taxi
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Situational Awareness
Anomaly: Other Unwanted situation
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airport; Chart Or Publication; Human Factors
Primary problem: Airport

Narrative: Before our passengers arrived I briefed our taxi route from the ramp to Runway 32. As we taxied out we followed the direction signs to Runway 32. As we followed the taxiway centerline around the air carrier ramp we noticed a 'restricted' sign way off to the left; approximately 20-30 yards prior to exiting the ramp. The ramp was not lit at all; leading us to believe there were access roads to the left off of the ramp prohibiting aircraft from entering. There were no paint markings or other signs on the immediate route to show that the taxiway ended and the service road began. Also; ahead and to the right down the 'old' taxiway was a sign showing the direction to Taxiway C1 that leads onto Runway 32. This is misleading; especially at night when the cues all point to a proper taxiway. Nobody was in danger nor was safety comprised. It is just misleading and further briefing could have caught this but with the lighting and signs in the area; it is very misleading. After we landed I called a ramp worker back at the FBO concerning the situation. He said [the confusion] happens all the time. I can really see this situation happening frequently; especially when the Tower is closed. I believe the problem could be prevented with additional markings and signage closer to the actual taxiway; also barricades or barriers could be used to prohibit aircraft in this area; since it was once a taxiway.In the daylight the route is probably very obvious; but at night the illusions become very confusing.

Callback: The reporter advised he was departing; after the Tower was closed; from an FBO facility on the northeast end of the U-shaped 'terminal' ramp and was taxiing via the ramp to Runway 32. His confusion occurred as he turned south-southeast toward the southeast end of the terminal ramp and saw the 'restricted' signs at the end of the ramp where an earlier location of Taxiway C still exists; although is not charted. It was only his reluctance to continue into the otherwise dark ramp area that caused him to look for alternatives at which time he saw Taxiway B and realized it connected to the 'new' Taxiway C; parallel to Runway 14/32.He believes that a sign exiting the FBO ramp advising uncontrolled/nighttime departures to utilize Taxiways 'A' and/or 'C' to access all runways would avoid the confusion and prevent the potential for larger aircraft to be trapped at the southeast end of the ramp; unable to reverse course and/or utilize the restricted and now uncharted old Taxiway C.The reporter further noted that; subsequent to filing his report; he had spoken to a Controller at the Tower who confirmed they were aware of frequent instances of departures actually taxiing down the southeast end of the ramp; some even deciding to continue down the (uncharted) old taxiway thence to C1 to the runway. The reporter was not pleased by the Tower Controller's failure to act on those events to preclude future such questionable operations.



Synopsis: A King Air flight crew; departing the terminal ramp for Runway 32 at EAU; was confused by taxiway signs to assist him in doing so safely. The confusion was increased by a 'restricted' sign at the end of the ramp from which it was reasonable to expect a taxiway to the runway.