To: lancair.list@olsusa.com
Date: Sun, 28 Feb 1999 09:45:08 -0800
Subject: Re:radar altimeter
Message-ID: <19990228.094509.-304969.1.refroelich@juno.com>
From: Robert E Froelich <refroelich@juno.com>
Mime-Version: 1.0

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Scott

I have been flying with a radar altimeter for more than 20 years (Bonzaar
before they went out of business and now Terra).  First in a Bonanza,
then in a turbo Aztec and now in a Lancair IV.  Currently flying in the
mountains.

I had an experience after a long day, before I had a radar altimeter,
flying a 3 hour VFR flight only to find IFR weather had moved into my
home airport.  The experience makes for me the radar altimeter a must if
flying IFR.  

The home airport glide slope was out for repairs, I broke out under the
clouds at about 500 feet, saw the runway lights and did not immediately
advance the throttles.  Next thing I noticed was a flash of strobe light
reflected off of a tree top.  Then I advanced the throttles, gained
altitude and made a safe landing.

Since I no longer fly IFR, my radar altimeter is set to give a note in
the headset at 900 feet (approx. pattern altitude).  It can be set for
decision height in 50 foot increments.  It gives an intermittent note as
you pass through 100 feet.  I do not use it for gear warning, but it can
be set for that.  It does not register any altitude above 2500 feet.   

I use the angle of attack unit for gear warning.  It says, "Landing gear"
if the gear is up and the speed is below 100 knots (a speed that I
decided on and set).

One fallacy with the radar altimeter is landing at St. George, Utah or
Morgantown, W.Va. and other airports that sit on a plateau.  The radar
altimeter could read several hundred feet above the ground while you are
actually below the runway elevation.  

The radar altimeter makes landing at a strange airport easier, in that
you do not have to know the altitude of the airport and then calculate
pattern altitude.  You just look at the altitude above ground (knowing
that the ground is fairly level between you and the airport).  

The other place a radar altimeter is helpful is over water.  It is very
difficult to judge  altitude over large bodies of water. 

This may be more that you wanted to know.

Bob