Can GPS be *too* accurate? Do I need some XTE??

"Icebound" wrote in message ...
In the "good old" VOR days, it must have been pretty difficult to fly down the centerline of an airway (or of any
direct track).

So an eastbound VFR/IFR aircraft descending from 7500/7000 to his destination, was more than likely to avoid
traffic... on the reciprocal track passing him by at 6500 or 6000... by some significant horizontal error-distance,
even if they didn't see each other (big sky theory :-) ).

GPS horizontal accuracy with WAAS is already in the order of magnitude of a Cessna's wingspan, and some are talking
about getting it down to mere inches.

So the question is: If my Westbound Cessna at 6000 feet (with the autopilot keeping it happily on the GPS-track
centerline) meets the descending Bonanza on the reciprocal track between the same two airports (using a similar
GPS/a-p combo), there is a distinct possibility that the horizontal clearance may be zero...

...so is there anything in the current crop of GPS and/or Autopilot systems that allow me to maintain a small
cross-track error of my choosing, without actually entering off-navaid-off-airport waypoints? ...or do we care; am I
overly concerned???



At midcourse, add a waypoint offset to one side or the other by a couple of miles. The enroute time would be changed
minimally...