SKS777flyer - I've done the same without cones. Observe markings on the ground in line with the wing tips and abeam the cockpit. Observe the locations after sitting in the seat.
Another method is while taxiing behind the same aircraft type observe what their wingtips pass over (laterally). As you pass the same spot observe where those marks/signs/man hole covers/grass spot, etc are on your side windows.
It's fairly simple from the seat position I favor(lower than 'official'). If I can see it in the FO's side window(R2) it's outside of the wingtip. On my side the extended wingtip line is about 1/3 of the distance above the lower screw (757/767) on the aft side of the on the L2 window.
Any doubt....stop. Come anywhere near my 'marks'...stop.
Last edited by misd-agin; 13th Apr 2011 at 17:16.
Reason: spelling