When trying for Gold Altitude in the West it can be very important to know
where the flight recorder thinks you are at 17,999'. With field elevations
near 7,000', getting the required 3000 meters gain means flying very close
to Class A, but not into it. We've had several badge attempts fail because
of differences in readings between the logger and the altimeter. We now
recommend setting the logger to field elevation and not exceeding 17,999
(well, 17,750 actually) on the logger display.

At lower field elevations, not so important.

John


"Don Johnstone" wrote in message
. com...
At 10:14 09 May 2012, Gary Patten wrote:
At 01:59 09 May 2012, akiley wrote:
I have a Colibri II (approved) flight recorder. This device allows
the user to adjust either the current altimeter setting, or adjust its
pressure altitude to match field elevation. Is this ok to do for
badge flights like silver/gold, or am I supposed to leave it set to
standard atmosphere?

....Aaron


If in doubt allways get the OO to take a photo of the gliders Altimeter
showing its settings matching what you have set your recorder too, and
declare what you've done pre flight

Why would you want to adjust a flight recorder to QFE? The data you are
interested in is the difference in height between the start of the soaring
task and the completion. It really does not matter what setting you use
QFE, QNH or standard atmospheric pressure as the two heights you are
interested in are the height after the completion of the launch and the
maximum height you achieve but the norm is to use standard atmospheric
pressure. It is not as though you are going to use the Colibri as an
altimeter in flight.
Other loggers do allow you to set QFE or QNH but the file is still
recorded
with the baseline at standard atmospheric pressure which does create
problems when checking for airspace violations when the limits of the
airspace are defined other than as a flight level.