The pilots of small aircraft can easily determine if they're clear of the runway by visually looking back through the side windows.

How do the pilots of big commercial jets determine that all parts of their aircraft are clear of the runway after landing? It looks like the same visual check as used by GA is almost impossible given the size of their aircraft. Do they have some special ways or measures to do that?

  • $\begingroup$ After takeoff or landing? $\endgroup$
    – Ben
    Jul 17, 2017 at 21:45
  • $\begingroup$ @Ben I meant after landing. $\endgroup$ Jul 17, 2017 at 22:43

1 Answer 1


Using TLAR (That Looks About Right). Pilot turns off a runway onto a taxiway spur and sees the runway safety area lines and just estimates a point beyond roughly equal to or greater than the length of the fuselage and places the cockpit over that point.

Other methods include geo-referenced airport diagrams on a moving map display showing the position of the aircraft.

  • 2
    $\begingroup$ Your answer begs me a question. Is it safe to use TLAR? What if their guess is wrong and the tail of the aircraft stays well outside the hold short line? I'm curious whether there was any accident caused by this. $\endgroup$ Jul 18, 2017 at 2:51
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    $\begingroup$ @lemonincider If they're still on the runway then the next flight will see that, and go around/not takeoff. Remember, all pilots have eyes, not just the ones vacating the runway. $\endgroup$ Jul 18, 2017 at 5:06
  • 4
    $\begingroup$ Yes it's fine. A lot of flying is estimation and being conservatively over. If he's no clear of the active the tower will growl at him to move. I've never heard of cases where pilots miscalculated clearing a runway on a taxiway. $\endgroup$ Jul 18, 2017 at 6:35
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    $\begingroup$ Wouldn't the tower generally be keeping an eye on runway clearance and directing loiterers to continue, also? $\endgroup$
    – Weaver
    Jul 18, 2017 at 6:52
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    $\begingroup$ @lemonincider My experience was in 747-100/200 in the 1990s, and back then at least TLAR worked fine. Pilots internalize (for lack of a better word) the size of the airplane they fly constantly, and they just know where the wingtips and the tail are going to be. I never heard of anyone leaving their tail out on the runway. A captain might have to remind a fresh first officer not yet accustomed to the airplane of something pertaining to the size of the aircraft, but people catch on quickly. $\endgroup$
    – Terry
    Jul 18, 2017 at 7:40

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