Seniors USA 2009 Start and Finish notes..... # 711 reporting

On Mar 18, 10:15*am, Tim Newport-Peace wrote:
At 16:15 18 March 2009, Jim White wrote:

Perhaps the simple answer is to mount your colibri on the panel and use
the
logged altitude reading as your reference for starts, airspace, and
finishes. You do however need to know the difference in feet +/- between
real QNH/QFE and QNE (1013.2). I write this on a sticky.

Jim

At 14:31 18 March 2009, Andy wrote:
On Mar 18, 7:00=A0am, Darryl Ramm *wrote:

It is my impression that many piltos with built in loggers like the
Cambridge 302 do not understand that the flight recorder is using
cockpit ambient pressure and not the static line-in on the rear of
the
instrument (only used for airspeed calculations). This is a
requirement to prevent the pilot being able to connect to the static
line and tamperer with logged pressure altitude.

I'm aware of that but I see now that what I wrote may be ambiguous.
Perhaps this would have been better:

"loggers (which cannot have an external static connection) will read
lower than
an altimeter which has an external static connection. "

Andy

Just to put the record straight, since AL4 (25 May 2001) Pitot Static MAY
be used. However some older designs may still be using Cockpit Static.

/*Quote

Pressure Altitude - In a GNSS FR, this is a five numeric group indicating
the pressure altitude in metres with respect the International Standard
Atmosphere (ISA) used in aviation, to a sea level datum of 1013.25 HPa.
The pressure recorded in the *.IGC file may either be "cockpit static"
(vented within the FR box), or use a tube connection to the pressure from
glider instrument system static tubing. If the pressure altitude signal
within the FR is used for other purposes such as cockpit instrument
readings which can be set to other datums such as
QNH or QFE, a one-way transmission system must be used from the sensor so
that the IGC file always records the required ISA to the 1013 sea level
datum irrespective of other settings used for flight instruments. The
permitted use of instrument-static is intended for a GNSS FR mounted in
the instrument panel. With such an installation, an OO as part of the
inspection of the FR installation must check the tubing and the pressure
connection to the FR to ensure that they will be out-of-reach of the
aircrew in flight. This is to prevent alteration to the IGC-file pressure
altitude record by any method. (AL4)

Unquote*/

Tim Newport-Peace >
Skype: specialist_systemshttp://www.spsys.demon.co.uk/icom.htm

Oops. Thanks.

And hopefully the ultimate thing is to point people to their the IGC
approval document for their flight recorder (see (http://www.fai.org/
gliding/gnss/), all the ones I've looked at (C302, LX series, and even
the new Triadis) use the cockpit ambient pressure. Without looking
though all the approval documents, does anybody know of ones that do
use the static line?


Darryl