New US Air 427 Hypothesis

From:         al683@freenet.carleton.ca (Scott Wright)
Organization: The National Capital FreeNet
Date:         29 Sep 94 00:15:38 
Followups:    1 2
Next article
View raw article
  or MIME structure



As of the time of this posting, I have not heard anyone mention
the latest area of investigation for the Pittsburgh crash.  CNN
reported today that investigators are now looking at the possible
role that wake turbulence might have played in this crash.  This
is the first time I have heard them mention the issue in the
news reports.

Interestingly, a few days after the crash, I happened to notice
a short article in a January or February issue of Aviation Week &
Space Technology that might be relevant.  The article referred to
an NTSB study into whether or not separations should be increased
for small to medium-sized jets on approaches when following 757s.
There have apparently been several reports of moderate turbulence
encountered by aircraft in the same weight class as the 737 that
were following 757s on approach.  (Does anyone know what type of
aircraft Flight 427 was following?)

While moderate turbulence would not normally put an aircraft out
of control, I wonder if it might not be enough to precipitate the
suspected intermittent hard-over rudder, or even a wing stall if 
it happened during the transition to an approach configuration.
While I doubt that the data recorder could detect the initial
turbulence, I would think that a detailed analysis of the data
would be able to either refute or leave open the possibility of
such a sequence of events.

It seems to me that a scenario like this (whether precipitated by
following a heavy aircraft or by a wind rotor) could also have
occurred with the COS 737 crash.  I don't think they ever firmly
established that the rudder controls were *not* a factor, and
I believe it had an older style of data recorder that provided
even less data for analysis.  Do you think they might be able to
link these two crashes?  Most people have discounted the link
because the current best theory for the COS crash assumes that
the mountain weather patterns were involved.

Please note:  I'm not trying to be sensational.  I just like to
to test my amateur knowledge against the professionals.  Sorry
if you don't think it belongs here.

Scott Wright


--
_____________________________________________________________________________
Scott Wright               "You can't have everything...
Ottawa, Canada                    Where would you put it?"
E-mail: swright@gallium.com                -Steven Wright (no relation)