Path: utzoo!attcan!uunet!ginosko!uakari.primate.wisc.edu!dogie.macc.wisc.edu!gatech!amdcad!military
From: cognos!sunray!roberts@uunet.uu.net
Newsgroups: sci.military
Subject: Re: XB-70
Message-ID: <27533@amdcad.AMD.COM>
Date: 28 Sep 89 07:13:08 GMT
References: <27497@amdcad.AMD.COM>
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From: cognos!sunray!roberts@uunet.uu.net
Sorry, still more on the crash of the XB-70 prototype at Edwards.

	[But providing some additional details , so I'm posting it. --CDR]

Following up to several postings on the cause of the crash:

I am fairly certain that the determined reason for the crash was pilot
error on the part of the pilot of the F-104.  His aircraft was caught in
the huge vortices generated in the area above and behind the six side-by-side
jet exhausts and slammed into one of the vertical stabs.  (Pilot error is a
somewhat brutal assessment, because no aircraft before or since the XB-70
has had the capability of generating such enormous forces in such a
restricted volume of air).  Most of the vertical stab was sheared off, and
the XB-70 went into a flat spin from which it was unable to recover.  There
is a fair amount of film footage of the accident available which shows all
of this.

When the crew tried to eject, the ejection sequencing failed.  Crew seats
deployed forward from the individual ejection pods, on little rails.  The
planned ejection sequence moved the seats back into the pods, closed the
pod doors, blew the aircraft skin hatches, and ejected the pods (hopefully
clear of the enormous vertical and horizontal surfaces).  The XB-70's flat
spin resulted in a very large centripetal force acting towards the nose of
the aircraft, based on the considerable distance of the cockpit forward of
the centre of rotation.  This force was apparently larger than the force
supplied for stage one of the ejection sequence, moving the seats back into
the pods.  (Only two crew were on board, in the left and right front seats.)

The crew member who did eject apparently managed to horse his seat into the
pod manually, by brute strength, and suffered severe injury in the process.
As I recall, the other crew member rode the aircraft into the ground,
because I think the ejection sequence was locked by the failure of stage
one.  The point is moot, ejecting with the seat deployed forward of the
ejection pod would not be survivable; in fact, it is unlikely that the pod
would clear the airframe, and the forces involved in a Mach-3 capable system
are extremely destructive.

Robert_S
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