Date: 202112
Local time of day: 1801-2400
Location: MSN.Airport, WI
Flight conditions: Marginal
Weather elements / visibility: Wind
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Taxi
ATC / advisory: Ground MSN
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Situational Awareness; Distraction
Second reporter function: Captain; Pilot Flying
Anomaly: Conflict Ground Conflict; Less Severe; Ground Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: Taxi
Result: General Flight Cancelled / Delayed
Contributing factors: Airport; Weather
Primary problem: Weather

Narrative: Taxing out to Runway 18 from ramp. Normal taxi route of H; Runway 32; B; M; M1 unavailable due to snow removal at Runway 32. Decided to taxi H; M; M1 because it was the next shortest route and the only restriction was the wingspan on east ramp of 150 feet. Our aircraft has a wingspan of 147 feet. When we turned onto M we were finally able to see that the taxiways did not have enough space to get thru due to aircraft parked in the triangle concrete area south of M and west of E. There were also a few fuel trucks that seemed to be within 20 feet of the Taxiway M center line just off of the FBO and it did not meet the clearance for our aircraft to get thru. No one was working at the FBO so nothing could get moved out of our way and we could not turn around. We had to have our maintenance cross runway 32 and push us back onto the ramp to taxi out to Runway 18 via a different route. Nothing else significant happened.The confusion of how the airport diagram depicts the east ramp on the taxi diagram. It shows that we should have been able to get through the taxi ways and not interfere with the east ramp. That was not the case.A more clear picture that the taxiway lines are apart of east ramp. Also if it has a wingspan restriction; not reducing that ability without a NOTAM.


Second narrative: Pushed from ramp to taxi to Runway 18 for departure.  Tower closed; non-tower ops in effect with snow removal in progress.  Usual taxi route under these circumstances is H - Runway 32 to B - M - M1.  Runway 14/32 was not accessible as it wasn't plowed.  So H - M - M1 seemed reasonable.  Jepp 10-9 page shows E Ramp accessible to aircraft with a wingspan of 150 ft or less (ours is 147' 1').  After we made the left turn onto M from H; we saw private jets parked in the triangle concrete area south of M and west of E.  They weren't really visible until turning onto M as it was night and they were sort of behind a snow bank.  There were also a number of fuel trucks by FBO where E and M meet.  The trucks seemed to be in the taxiway somewhat.  The combination of the jets and trucks made the gap between them unsafe to try and navigate.  Contacted an airfield ops vehicle via CTAF and they tried to find someone at the FBO to move the trucks; but were unsuccessful.  Contacted the ramp and they sent out the tug and pushed us back to the south ramp where we taxied out a different route.Cause - Nighttime; non-tower ops; snow on the airfield; previously unused and unfamiliar taxi route; FBO possibly parking things in the taxi lane (no idea what their restrictions / requirements are).Suggestions - It seems that the whole east ramp area; even though it's open to our type aircraft; should probably be restricted from use by our company aircraft...doesn't seem like a good idea generally speaking taxiing over there.  Put a note on the taxi chart and Company page to avoid the east ramp area.


Synopsis: Air carrier flight crew reported ramp congestion and charting issues at MSN airport.