NavList:

From: Ken Gebhart <gebhart@celestaire.com>
Subject: [NavList] Re: FAA-H-8083-18 - Flight Navigator Handbook
To: garylapook@pacbell.net
Date: Monday, June 17, 2013, 11:34 AM

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I have a slightly different take on this issue.  Whenever a control input is made, an acceleration is imparted to the bubble. It is my belief that the only need for an averager is to compensate for the inputs made by an autopilot or second pilot, and natural oscillations of the plane such as dutch roll. So, I prefer a single shot with the sextant.  In preparation, take some practice sightings with the sextant to get the altitude set, star identified, etc.  Then for the actual shot, carefully trim the plane for "hands off".  Then quickly grab the sextant and take a quick shot. This should take less than 3 to 5 seconds.  Then quickly check the heading and airspeed.  If nothing has changed, You should have a good reading.  It would be interesting to compare the two methods.  

Ken

On Jun 17, 2013, at 12:37 PM, Gary LaPook wrote:

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--- On Mon, 6/17/13, Andrés Ruiz <navigationalalgorithms{at}gmail.com> wrote: From: Andrés Ruiz <navigationalalgorithms{at}gmail.com> Subject: [NavList] Re: FAA-H-8083-18 - Flight Navigator Handbook To: garylapook{at}pacbell.net Date: Monday, June 17, 2013, 5:55 AM Thanks Gary for the information, very illustrative videos. Two questions: - Could you give references about current aircraft sextant manufacturers? Nobody makes them anymore. - Without an autopilot an aircraft bubble sextant is suitable for shooting when the pilot and the navigator is the same person?. Yes. Note your heading then you level the wings, put the sextant to you eye, start the averager, follow the star for a few seconds, level the wings again back on heading, start shooting again note the ending heading so you can apply the "wander correction" if necessary. It works better in smooth air or with a copilot or autopilot. I took most of my in flight shots with an A-10A and I took some sights where more than half of the averager disk had marks showing that the instantaneous readings had ranged more than two degrees due to turbulence but still ended up with a usable average altitude. Almost all of my sights were taken while I was flying solo, only  few with a copilot, and not many with an autopilot. gl --  Andrés Ruiz Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/ : http://fer3.com/arc/m2.aspx?i=124378

: http://fer3.com/arc/m2.aspx?i=124383

: http://fer3.com/arc/m2.aspx?i=124384