Seems a little strange-

"jsmith" wrote in message ...
Domestic Reduced Vertical Separation M?? begins at FL280.
Prior to January 20, 2005, vertical separation between aircraft above FL280 was 2000 feet. As of 20 January 2005, the
vertical separation between aircraft at FL280 and above is 1000 feet. Only aircraft properly equipped for DRVSM are
permitted to fly above FL280.


Altimeter accuracy ±65' for current birds and ±130' for older ones. Pretty amazing stuff actually, something like 1/4 of
1%...

On Tue, 25 Jan 2005 23:15:41 GMT, "Blueskies"
wrote:


"jsmith" wrote in message ...
Domestic Reduced Vertical Separation M?? begins at FL280.
Prior to January 20, 2005, vertical separation between aircraft above FL280 was 2000 feet. As of 20 January 2005, the
vertical separation between aircraft at FL280 and above is 1000 feet. Only aircraft properly equipped for DRVSM are
permitted to fly above FL280.


Altimeter accuracy ±65' for current birds and ±130' for older ones. Pretty amazing stuff actually, something like 1/4 of
1%...


Pretty sure that the ±65' and ±130' tolerance is for the "automatic
altitude control system" in regard to the "acquired altitude" in
"straight and level flight under nonturbulent, nongust conditions". If
there is an altitude select/acquire system, it's tolerance is ±25'
between the selected/displayed altitude and the corresponding signal
to the autopilot.

The tolerance for altimetry error is roughly between ±140' and ±200'.
There is also a requirement for an altitude alerter with a nominal
±200' ±50' (newer aircraft) and ±300' ±50' (older aircraft) alert
threshold.

If these numbers have changed recently, I apologize, am looking at
older reference/study material.

TC

wrote in message ...
On Tue, 25 Jan 2005 23:15:41 GMT, "Blueskies"
wrote:


"jsmith" wrote in message ...
Domestic Reduced Vertical Separation M?? begins at FL280.
Prior to January 20, 2005, vertical separation between aircraft above FL280 was 2000 feet. As of 20 January 2005,
the
vertical separation between aircraft at FL280 and above is 1000 feet. Only aircraft properly equipped for DRVSM are
permitted to fly above FL280.


Altimeter accuracy ±65' for current birds and ±130' for older ones. Pretty amazing stuff actually, something like 1/4
of
1%...


Pretty sure that the ±65' and ±130' tolerance is for the "automatic
altitude control system" in regard to the "acquired altitude" in
"straight and level flight under nonturbulent, nongust conditions". If
there is an altitude select/acquire system, it's tolerance is ±25'
between the selected/displayed altitude and the corresponding signal
to the autopilot.

The tolerance for altimetry error is roughly between ±140' and ±200'.
There is also a requirement for an altitude alerter with a nominal
±200' ±50' (newer aircraft) and ±300' ±50' (older aircraft) alert
threshold.

If these numbers have changed recently, I apologize, am looking at
older reference/study material.

TC

Yup, I looked at the docs again and it looks like you got it right, except the total altimetry system error may not
exceed 120 feet for pre-97 planes and 80 feet for recent birds....

You are correct, sir.

Unless it's a non "group" aircaft, then it's 160 feet in the basic
envelope, and 200 feet in the full.

Am thinking I just fulfilled my recurring RVSM training requirements
while on Usenet.

Gotta love those federal regulations...

TC