How Aircraft Can Be Caused to Crash In Conditions Of Low Ceiling/
Visibility

Not A theory on the Wellstone crash and other aircraft crashes
involving political persons per se, just some thought-provoking
facts.

NOTE: It cannot be emphasized enough that tampering with air
navigation equipment, or in any way interfering with the safe flight
of aircraft by transmitting spurious signals or otherwise, is a
Federal crime subject to the most severe penalties. In no way is the
following to be construed as advocating, facilitating or encouraging
any criminal act against aircraft or airports. This information is
provided SOLELY for the purpose of discussion in the context of
suspicious accidents involving aircraft, and to demonstrate the
simplicity of creating aircraft "accidents". Technical details that
would allow construction or operation of practical devices to cause
aircraft crashes have very purposely NOT been detailed, and certain
essential elements of the information below have been deliberately
skewed to be misleading. Note, however, that these distortions do not
alter the concept.

First a brief tutorial:

In conditions of low ceiling and/or low visibility, pilots rely on
instruments to keep them informed of an aircraft's altitude, attitude,
air speed, rate of climb or descent, etc. This is most important when
shooting an approach in high-performance aircraft under poor weather
conditions, when small errors can have tragic consequences.

Icing on airfoil surfaces can greatly influence a plane's stall speed
- an important consideration on final approach - but modern stall
warning indicators normally give ample warning of this sort of problem
and prompt the pilot to apply power before airspeed drops below
critical level. Most pilots practice stall-recovery on such a regular
basis that corrective measures are a natural reaction. If this were to
occur during approach, the pilot might decide to land provided there
were time to recover proper airspeed and control, or to abort the
approach and go around again.

When making a controlled descent through cloud cover, the altimeter
and rate of descent indicator are all-important, since a pilot cannot
(always) see the ground until he descends clear of the cloud cover or
ceiling. Two types of altimeters are in common use, the "manual" type
and the "radio" type. Both rely on the instrument being set to the
correct barometric pressure so as to indicate altitude accurately.

Altimeters:

Manual altimeters (common on small single-engine aircraft) are
adjusted by turning a knob to calibrate the altimeter to the local
barometric pressure. This is done before takeoff by setting the
instrument to the known runway elevation and may be readjusted for
changing conditions enroute by monitoring weather frequencies for
local barometer readings. Every novice pilot learns the rhyme "Low to
high, you're flying high. High to low, look out below." This reflects
the fact that when flying from an area of low pressure into a higher
pressure zone, the altimeter will indicate a lower-than-actual
altitude, meaning the aircraft will be higher than the altimeter
indicates. When flying from a high pressure area into a lower-pressure
one, the reverse is true and the aircraft will be lower than the
altimeter reading. There have been many accidents due to failure to
properly maintain correct altimeter settings. Such accidents most
often occur under IFR conditions in mountainous terrain and on
approach to landing.

Radio-altimeters (more common on high-performance and multi-engine
aircraft) are "self-adjusting" in the sense that they receive coded
barometric pressure signals transmitted from area service centers, and
automatically apply the necessary correction on a regular basis.

Approach Navigation:

Several Instrument Approach systems are in common use at general
aviation airports. Disregarding the highly sophisticated systems found
at large commercial or hub airports, approach systems may be
categorized as "Non-Precision Instrument" (NPI) and "Precision
Instrument" (PI) systems. Simply put, both types provide pilots with
information on the orientation of their aircraft relative to the
runway threshold, in terms of heading or course as well as approach
slope or glide angle. NPI systems typically rely on a Non-Directional
Beacon (NDB) and high intensity lights as well as other visual aids
such as the "Precision Approach Position Indicator" (PAPI). In
addition to lighting and visual aids, Precision Instrument approaches
incorporate electronic "NavAids" such as radio position markers and an
electronic Glideslope transmitter that provides a directional "beam"
to guide the aircraft in its descent to the runway. Full Instrument
Landing Systems (ILS) may include even more sophisticated position
locating equipment.

Effects Of False Signals:

1) Altimeter error:

As noted above, radio altimeters incorporate very-high-frequency (VHF)
radio receivers that allow them to continuously re-calibrate
themselves on the basis of encoded barometric information. However,
reception is only possible at altitudes high enough to afford a "line-
of-sight" to the transmitter. As an aircraft descends to lower
altitudes, the line-of-sight becomes less and signal strength is
reduced. When the signal is finally lost, the radio altimeter remains
set to its last calibration, which in normal circumstances is
completely accurate for the area of operation.

If a "false" altimeter transmitter is set up somewhere in the vicinity
of the landing zone, its signal will overpower and ultimately replace
the true signal as the aircraft descends. A deadly situation is
created if the encoded signal is such as to cause the aircraft's radio
altimeter to gradually recalibrate itself to a much lower barometric
reference point, since this will have the effect of indicating a much
higher-than-actual altitude. In low ceiling conditions at NPI airports
not equipped with an electronic Glideslope (such as Eveleth-Virginia),
a pilot may thus be made to think he is hundreds of feet higher than
he actually is. If the ceiling is only 200 feet or so (as it was at
Eveleth), the pilot would only become aware of the error when he broke
through the cloud base at 200 feet, at which altitude - and at a
descent rate predicated on a higher altitude relative to the runway
end - it would be too late to correct without stalling and crashing
the aircraft.

This type of "sabotage" would be extraordinarily simple to effect for
anyone with a knowledge of radio transmitters, would not require
disabling any air navigation equipment, and could make use of a
recorded or computer-generated encoded datastream.

2) NavAid error:

It is also possible to position a "false" Glideslope transmitter a
mile or so from the runway end and simultaneously disable the real
one. In conditions of poor visibility, this could cause an aircraft to
"land" catastrophically short of the runway. If Marker Beacon antennae
were similarly relocated, an aircraft could be totally disoriented. It
was exactly this kind of sabotage that was implicated in the crash of
a junbo-jet on a far-east mountainside ten or fifteen years ago. The
details escape me now, but the case attracted attention because some
high officials of something or other were killed. It was theorized at
the time that a glideslope transmitter had been mounted on a military
jeep parked in the jungle at some distance and at right angles to the
runway. When the pilot reached what he thought was the marker, he
turned and began his descent - right into the mountainside.

This kind of thing would require considerably more organization than
the scenario in 1) above, but it's certainly feasible for those with
the motivation and skill, not to mention those with ready access to
the necessary technical toys.

http://la.indymedia.org/news/2002/10/20736.php

More on EMP and how to murder a powerful political candidate. Who will
be next?

Weapons of Mass Destruction (WMD)

http.//www.rense.com/general15/gates.htm
http://www.angelfire.com/or/mctrl/microwave.html
http://www.skolnicksreport.com/aircrashes.html
http://www.voxfux.com/archives/00000039.htm
http://www.globalsecurity.org/wmd/library/report/1984/ERD.htm