Ah, I smell a philosophical difference. Since I'm not flying over trackless
wastes, have Loran, GPS, VOR's, finger on the sectional, etc., the plan is
just that, a plan. Like a battle plan, it starts to degrade at first
contact with reality.

The purpose of the spreadsheet is to give me the best prediction of fuel
burn, arrival times, and initial headings that can be generated a couple
hours before leaving for the airport. The probability that conditions will
change significantly is fairly low. Even lower is the probability that the
conditions I encounter will exactly match the forecasts. Although the plan
is a valuable guide to the flight and rough reality check on in-flight
calculations, it's really more of a "Pick me up at the airport at ____" tool
than a "where am I now" tool.

If I get a final briefing and find out that the winds are say 10% stronger
and have veered 30 degrees, I probably wouldn't rework the whole thing but
just make top of the head adjustments to the numbers. Initial headings are
just a convenience to help me settle down on the electric box's "Direct to"
pointer. Similarly, if I start running ahead or behind of my times to
waypoints, I'll just project ahead a similar approximate correction.

The spreadsheet is not a substitute for the Wiz Wheel or Electronic E6B. If
there is a significant change, say a 10 knot tailwind swinging around to a
25 knot headwind, I might sit down and rework the whole thing by hand with
the blank sheets I carry in my flight bag. More likely, in that case, I'll
be worried about the time, just make an overall correction, and interpolate
the rest as I go along. The plan, even though based on different wind
assumptions, still makes those gut estimates easier. Since I don't have a
$1000 headset or Oregon Aero seats, I don't fly very deep into my fuel
reserves anyway.

I have yet to find a reason to fiddle with the E6B in flight. There are too
many other ways to get the same answers while keeping eyes outside the
cockpit. Set your heading without wind correction, pick a landmark on the
horizon, then pick one closer. Crab until they stay in line, then hold that
course. Fly 10% of the distance to a waypoint and time it, now you know
your arrival ETA.

The most important VFR flight instrument is still the sectional on the lap
and the fingernail. When the GPS blips off, or the panel goes dark, that's
what will get you down safely.

--
Roger Long