Narrative:

Early afternoon I received taxi instruction from tus ground for taxi from the FBO. I was advised to taxi delta to runway 11R. Upon approaching 11L; was advised by ground to continue and cross runway 11L which I did. I was observing foreflight ipad taxi diagram and [was] unfamiliar with the airport never having been there before. I noted on taxi diagram that gray color taxiway did not seem to actually cross the runway and assumed it was ok to continue with that area looking clear of the actual runway. I accidentally went further on the delta taxiway than I realized; apparently being near the approach area of runway 11R. Ground control notified me to hold short runway 11R but by then I was in the middle of that area so advised them that I was already almost across that area. Believe the diagram is somewhat confusing due to the gray taxing area color as opposed to the black color for the runways on the diagram. If the approach area at delta and the intersection of both runways were black; feel it would be a bit more obvious of the runway area. Runway 11R is also very narrow and easy to miss at that location. I realize it is a 'hotspot' area but initially missed it.

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Original NASA ASRS Text

Title: A Corporate pilot unfamiliar with TUS and using an iPad; was cleared to cross Runway 11L but could not visually identify or did the EFB Airport Chart indicate Taxiway D as an extension of Runway 11R and so he taxied onto it.

Narrative: Early afternoon I received taxi instruction from TUS Ground for taxi from the FBO. I was advised to taxi Delta to Runway 11R. Upon approaching 11L; was advised by Ground to continue and cross Runway 11L which I did. I was observing Foreflight iPad taxi diagram and [was] unfamiliar with the airport never having been there before. I noted on taxi diagram that gray color taxiway did not seem to actually cross the runway and assumed it was OK to continue with that area looking clear of the actual runway. I accidentally went further on the Delta taxiway than I realized; apparently being near the approach area of Runway 11R. Ground Control notified me to hold short Runway 11R but by then I was in the middle of that area so advised them that I was already almost across that area. Believe the diagram is somewhat confusing due to the gray taxing area color as opposed to the black color for the runways on the diagram. If the approach area at Delta and the intersection of both runways were black; feel it would be a bit more obvious of the runway area. Runway 11R is also very narrow and easy to miss at that location. I realize it is a 'Hotspot' area but initially missed it.

Data retrieved from NASA's ASRS site as of July 2013 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.