Glider down near Reno - pilot OK

In the vertigo induced confusion of IMC in high wind wave conditions, I'd
not recommend relying on most of what you wrote. Pushing the nose over to
increase ground speed at altitude and in high wind, can almost instantly
result in exceeding VNE. IMC is no place for trying to convince your ground
track "confused" GPS to rescue your butt! Nor would one likely have the time
to change speed and try to evaluate what the GPS is telling you - - and then
try to equate that to roll. The loud bang, indicating departure of wings,
would likely interrupt this process.

Better to be prepared and fly with both training and some sort of horizon
reference, be it Tru-trak, PC Flightsystems or MGL. PC flightsystems has a
new one that looks interesting http://www.pcflightsystems.com/EGYRO2.htm.
I'm happy with my Tru-trak and the Garmin 196 panel page (the 196 for
reasonable wind conditions).

bumper (instrument rated :c)
Minden, NV



wrote in message
oups.com...
GPS heading is based on, obviously, your ground track (the GPS has no
knowledge of your airspeed or magnetic heading). If your ground speed
is low, or zero, (as may well be the case in wave) the GPS heading is
useless. The only way to get useful information is to speed up so that
the ground speed is, at least, a healthy fraction of the airspeed (say
25-50%). This, of course, means you are no longer "parked" in the wave
and are moving relative to the ground. In your crabbing scenario, a
wind speed change will lead to a change in your heading over the
ground. In IMC, the pilot will not know whether he rolled or whether
the wind changed, at least not immediately. If he rolled, however, the
heading will continue to change, while if the wind speed changed to,
and remainded constant at, a new value the heading will initially
change and then remain at the new heading. In both situations the pilot
can react be rolling the opposite direction and either:

1. correct the roll
or
2. commence a turn that returns the heading to the desired point.

A better solution for strong wave conditions is an artificial horizon,
which are now available in electronic form (although the power
consumption is somewhat higher than I would like). But GPS can still be
used for an emergency descent in IMC conditions, IF you keep your
airspeed significantly above the wind speed.

Tom

Pushing the nose down won't "instantly" result in exceeding Vne! If you
are going to fly wave you had better now what your speed limits are at
altitude. If you don't, DON'T GO!!

If you are close to Vne then you will have to turn down wind and suffer
the consequences.

I have descended thru 7K feet of IMC on just a compass, altimeter and
ASI; I wasn't confused, nor was I suffering from vertigo. That can
happen to pilots regardless of their equipment. If you don't believe
me, just ask JFK Jr (or his heirs). There will be those who chose not
to equip their gliders with artificial horizons; I am simply advising
them of their options should they encounter inadvertant IMC. You can
tell them that they shouldn't fly wave w/o an artificial horizon, but
they will anyway. When the s**t hits the fan, you use what is
available.

Tom