Re: Korean Air 801 crashed on approach to Guam

From: (Larry Stone)
Date:         08 Aug 1997 18:50:31 -0400
Organization: Kapor Enterprises, Inc.
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In article <5sd6ah$gd0$>,
(Ernie Alston) wrote:

> At about 200 Ft a small alarm goes off letting the pilots know they
> are at decision height (DH). If they don't have the runway right in front
> of them, and are not comfortable with their approach by then, again its
> an automatic go around for another try.

That's not part of standard ILS receiving equipment (unless you mean the
middle marker). Many airplanes (almost all commercial transports) have
altitude alerters than sound an audible warning when the plane approaches
a pilot-set altitude. Also, a "standard" part of an ILS (but not present
on every ILS) are the marker beacons. The outer marker is about 5 to 6
miles from the runway and is approximately at the altitude the plane will
intercept the glideslope. The middle marker is approximately at the point
where the glide slope is 200 feet above  the runway, and the inner marker,
at the few places that have them, is at roughly 100 feet. These are all
radios that will cause a light to flash on the panel and, if you have it
selected, be heard over the radio speakers or headphones.

> I'd be interested to know from the CVR if that went off.

Note that markers are fixed on land and are not tied to the airplane's
altitude. From what I've heard, the plane was a few miles from the airport
so if it's the middle marker you're referring to, they would not have
heard it as they were not there.

-- Larry Stone ---
   Schaumburg, IL, USA