[Milsurplus] [ARC5] OT: What is the purpose of the 4th pointer on my Kollsman 671CLU-4-038 pressure altimeter?

[Jim Degenhart]

The other possibility is it needs a power source. If you check local 
weather and set the HG to local it should read the local ground elevation.

Jim

KF9XK



On 7/12/2016 8:15 AM, Clare Owens wrote:
> It was Ebay #201615219209? and in the picture for the listing the edge 
> pointer is at about 4.3 and the In. Hg is set to 30.55.  I did a 
> recalibration last night and noticed that although the three altitude 
> pointers stayed stationary, the edge pointer moved along with the 
> inches of mercury dial, so now it's at 8.4, with the In, Hg set to 
> 30.10.  It moves along with the In. Hg dial but the numeric 
> relationship escapes me...
>
> Thanks to all of you for the replies,
>
> Clare
>
> On Tue, Jul 12, 2016 at 2:06 AM, Sheldon Daitch <SDAITCH at bbg.gov 
> <mailto:SDAITCH at bbg.gov>> wrote:
>
>     Looking at eBay item 351778486635, it makes sense, now.
>
>     The  orange triangle is a reference altitude marker and is set
>     with the lower right know.
>
>     This unit is a high end altimeter system, and as noted, from a
>     B737/747 system.  Looks like it is from the older systems, steam
>     gauges as some pilots call them.
>
>     I've never flown an aircraft with that high end equipment, not on
>     my budget, and I have to make some guesses.  I don't think the
>     orange triangle marker is settable other than somewhere in the
>     1000 foot range, and usually set per one B-737 ops manual for the
>     minimum descent altitude on an instrument approach.  I also
>     suspect that altimeter pictured also has an output to an alerter
>     in the  cockpit to tell the pilots they are at MDA.
>
>
>
>     73
>
>     Sheldon
>
>
>
>     ------------------------------------------------------------------------
>     *From:* ARC5 <arc5-bounces at mailman.qth.net
>     <mailto:arc5-bounces at mailman.qth.net>> on behalf of Clare Owens
>     <clare.owens at gmail.com <mailto:clare.owens at gmail.com>>
>     *Sent:* Tuesday, July 12, 2016 1:18 AM
>     *To:* Discussion of AN/ARC-5 military radio equipment.;
>     armyradios at yahoogroups.com <mailto:armyradios at yahoogroups.com>;
>     Milsurplus
>     *Subject:* [ARC5] OT: What is the purpose of the 4th pointer on my
>     Kollsman 671CLU-4-038 pressure altimeter?
>     Hi All,
>
>     The altimeter has the usual three pointers in its center, for
>     100/1000/10000 feet.  But it also has a little triangular pointer
>     that rotates around the edge of the dial and moves at about the
>     same speed as the 100 foot pointer.  When the three normal
>     pointers are at zero, the one on the edge ia pointing to just a
>     little below 6.8.  Seems odd and I can't find any reference to the
>     edge pointer on line.
>
>     It looks like this unit needs to be recalibrated and I've found
>     instructions for that.
>
>     The altimeter has the typical Navy "US with anchor" stamp on its back.
>
>     Any Navy aviators out there?
>
>     Thanks,
>
>     Clare
>
>
>
>
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