Subscriber question:
"Are you every allowed to taxi across the double-solid, double-dashed lines at an airport coming from the side of the solid lines without explicit permission from Tower or Ground?" —
Martin:
“If you cross the line, you’ve crossed the line. We’ve all seen this in FAA pamphlets trying to combat the concerning trend of increasing runway incursions. ‘The line’, of course, refers to the double solid and double dashed yellow lines on the pavement, markings, which separate runways from taxiways. The FAA calls these Runway Holding Position Markings. Coming from the side of the two solid lines, explicit ATC permission is always required at a controlled airport before crossing any such runway holding position markings.
Or is it? Actually, permission is not always required. AIM section 2-3-5 a. lists two exceptions. First, at airports that exercise land-and-hold-short (LAHSO) operations, those same markings can be found on a runway, but pilots only need to hold short if ATC has requested they do so—only when land-and-hold-short operations are in effect. No surprise here.
It’s the second exception that sometimes surprises pilots: It’s when such markings protect the approach path of a nearby runway and crossing over the lines could put you close to an airplane still in the air, approaching a nearby runway. You will find ‘APCH’ in white letters on a red sign next to the taxiway, In this case, you only need to stop if ATC has explicitly asked you to.
So, for efficiency, it pays off to know the difference between markings protecting runways and markings protecting approach paths. Though it goes without saying that if you are not 100 percent confident whether you can cross one of those lines, stop and ask ATC so they can clarify.”