Narrative:

A potential ground mishap is very real at seatac airport. While aircraft taxi for takeoff (especially to the north runways 34L and 34R/taxiway Q) numerous planes line up. Meanwhile as planes land and taxi back to concourse B, south, or a gates, these aircraft are routinely asked to taxi east of the planes on taxiway B. This is a very tight fit and requires pilots to determine their own wingtip clearance which is very difficult and something they are not trained for. This is the only airport in the USA that I can think of where pilots are required to provide their own wingtip clearance. In addition, there is a vehicle road near the concourses. Numerous large trucks also pose a ground mishap potential as aircraft 'squeeze' between aircraft to the west and vehicles to the east. On many aircraft pilots cannot even see their wingtip from the cockpit. Suggestion: paint a dotted line east of taxiway B which we can taxi on and list the aircraft types which can utilize this dotted line and can safely pass certain aircraft types on taxiway B. Put this information on the 20-9 page so pilots know for sure which aircraft they can safely pass while keeping clear of vehicle traffic too.

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Original NASA ASRS Text

Title: A B737 PLT IS CONCERNED THAT MULTIPLE TAXI LANES BETWEEN CONCOURSES B, C AND THE RAMP EDGE ON TXWY B AT SEA ARE INADEQUATELY MARKED AND MAY CONSTITUTE A HAZARD WHEN INBND ACFT ARE INSTRUCTED TO PASS ABEAM ACFT AWAITING DEP ON THE NBOUND RWYS AT TXWY Q.

Narrative: A POTENTIAL GND MISHAP IS VERY REAL AT SEATAC ARPT. WHILE ACFT TAXI FOR TKOF (ESPECIALLY TO THE N RWYS 34L AND 34R/TXWY Q) NUMEROUS PLANES LINE UP. MEANWHILE AS PLANES LAND AND TAXI BACK TO CONCOURSE B, S, OR A GATES, THESE ACFT ARE ROUTINELY ASKED TO TAXI E OF THE PLANES ON TXWY B. THIS IS A VERY TIGHT FIT AND REQUIRES PLTS TO DETERMINE THEIR OWN WINGTIP CLRNC WHICH IS VERY DIFFICULT AND SOMETHING THEY ARE NOT TRAINED FOR. THIS IS THE ONLY ARPT IN THE USA THAT I CAN THINK OF WHERE PLTS ARE REQUIRED TO PROVIDE THEIR OWN WINGTIP CLRNC. IN ADDITION, THERE IS A VEHICLE ROAD NEAR THE CONCOURSES. NUMEROUS LARGE TRUCKS ALSO POSE A GND MISHAP POTENTIAL AS ACFT 'SQUEEZE' BETWEEN ACFT TO THE W AND VEHICLES TO THE E. ON MANY ACFT PLTS CANNOT EVEN SEE THEIR WINGTIP FROM THE COCKPIT. SUGGESTION: PAINT A DOTTED LINE E OF TXWY B WHICH WE CAN TAXI ON AND LIST THE ACFT TYPES WHICH CAN UTILIZE THIS DOTTED LINE AND CAN SAFELY PASS CERTAIN ACFT TYPES ON TXWY B. PUT THIS INFO ON THE 20-9 PAGE SO PLTS KNOW FOR SURE WHICH ACFT THEY CAN SAFELY PASS WHILE KEEPING CLR OF VEHICLE TFC TOO.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.