Message-ID: <3788C4C5.F7A12FA3@regandesigns.com>
Date: Sun, 11 Jul 1999 09:22:29 -0700
From: Brent Regan <brent@regandesigns.com>
To: lancair.list@olsusa.com
Subject: Re: GPS Certification
References: <19990711040154.AAA27489@truman.olsusa.com>
Mime-Version: 1.0

          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
Michael posted:

> Jim says: " According to AC 20-138, the FAA accuracy predictions assume
a 5 degree "mask angle", which I am assuming to mean that the sky is
obstructed from the horizon to 5 degrees above the horizon.  I'm
guessing yours will be more like 30 or 40 degrees through a significant
azimuth arc in the forward direction. If I can find somebody that knows
how to calculate the effects of the obstruction, we can try it that way."
<<<

In the movie The Great Race one of the racers proclaims "What is behind
you is not important!", not so in this case. It would seem that the
"masking angle" will be violated by ANY installation IN the Vstab, by the
rudder. In order to get a clear view of the sky you would need to be
mounted either on top of the fuselage (near the pilot's head) or on
TOP of the Vstab, like a Cessna beacon :(

Looks like you will be running the test. Let us know the results.

Thanks.

Brent Regan

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML homepage:   http://www.olsusa.com/Users/Mkaye/maillist.html