Re: JEFX over Pahrump 4/22

In article <beb1eb7f-8a1e-4307-aed9-c79eff15e312
@u9g2000prm.googlegroups.com>, miso@sushi.com says...

On Apr 21, 7:05�pm, <nos...@notreal.com> wrote:

In article <ff71e2d8-47a2-49ed-b837-c416a8b7d963
@x18g2000prb.googlegroups.com>, m...@sushi.com says...

The JEFX exercise running now at Nellis is supposed to have some sort
of activity over Pahrump. This is the notam for the event.

A0984/10 - QRACA THERE IS A STATIONARY ALTRV IN THE PAHRUMP NEVADA
AREA BOUNDED BY THE FOLLOWING
POINTS: 3622N/11554W 3604N/11554W3604N/11612W 3630N/11630W 3630N/
11610W TO POINT
OF ORIGIN. ACTIVE FROM 10000 TO 14000 WITH HIGH SPEED MILITARY
AIRCRAFT. ALL
NON PARTICIPATING TRAFFIC IS ADVISED TO AVOID THIS AREA. NOTE: THIS
ALTRV EFFECTIVELY
CLOSES V135 BETWEEN
10000 FT-14000 FT DURING THE ACTIVE TIME FRAME. SEE TEXT - SEE TEXT,
22 APR
19:00 2010 UNTIL 22 APR 22:00 2010. CREATED: 17 APR 19:22 2010

This translates to more or less:
There is an altitude reservation in the Pahrump Nevada area bound by
(coordinates) from 10000 to 14000 ft above ground level with high
speed military aircraft. blah blah 22 April noon until 3PM PDT.

I'm told the ground staging is at the Calvada Air Park.


I am not sure if that is a NOTAM or not but as a rule, I would be very
surprised if they gave an advisory to pilots that was in AGL and not
MSL. �Just about everything I am familiar with concerning altitudes for
aircraft is given in MSL as that is what the standard barometric
altimeter indicates. �Also it would drive the pilot crazy trying to
figure out AGL, particularly over uneven ground as it would be
constantly changing. �


That is a notam since I copied it from https://www.notams.jcs.mil.

There is a transitional altitude where you change from AGL to MSL. If
you are flying low, you want AGL since the maps have obstructions in
AGL. After the transition altitude, you fly MSL so ATC can maintain
vertical separation.  Also above the transition altitude, you fly at
flight levels, not altitude per se. I'm not a pilot, but that is my
understand of how they write the notams.

There was a classic Blue Angels accident related to AGL versus MSL.


Actually I believe obstruction heights even on VFR sectional charts are 
given in MSL.   They show the AGL heights in parenthesis for 
informational purposes but the pilot is mainly interested in what the 
height of the obstruction is in reference to what is altimeter is 
indicating.