From: cid@athena.mit.edu (Derek H Cedillo)
Subject: Re: Aplogy to Robert Dorsett & More on El Al Disaster
Organization: Massachusetts Institute of Technology
Date: Tue, 13 Oct 1992 00:39:07 GMT

In article <1992Oct12.173032.17438@airdata.socal.com> chris@airdata.socal.com (Chris J. Davis) writes:
>In article <1992Oct10.214334.23045@athena.mit.edu> cid@athena.mit.edu (Derek H Cedillo) writes:



>[ 99 lines deleted ]
>>The cross sectional area of a turbofan such as the CF6-50 (GE's 747-
>>200 powerhouse-BTW what is the PW engine?  it's an old J line right?)
>
>it's a JT-9D i believe (Robert?)
>
>[...]
>>It would take a lot more than one bird in an engine to cause serious
>>problems like an uncontained failure.
>
>doesn't this depend on the size/mass of the bird?  what about one _big_
>bird?  (no derek, not the one on sesame street).  does anyone have some
>actual _facts_ on this?

I can't tell you for the 747 thrust range engines.
But in testing the GE CF34 (regional jet engine, Brother of
the A-10 Powering T34) The equivilent of about an 8-11 pound turkey
was the size of the bird tested.  Mostly they consider geese
and pheasant (depending on the area) the biggest threat.

>[...]
>and derek continues in the same sincerely apologetic tone:
>
>>And what do you know?  The key word here is "UNLIKELY", not "impossible".
>>My, you have a lot of hostilities pent up inside don't you? 
>>Before you explode, read more carefully.

He agreed with me, yet was trying to contridict.  To me that was senseless.

>[...]
>let's join derek now as he sets himself up for his next apology:
>
>>Bah! You piss me off right here!
>>Boy if I was an owner of any type of firm, I would sure hope you never
>>worked for me.  You make me sick.

I will not apologize for that kind of work ethic.  Some one who says
"Only after persistent catastropic failures of a component should we
"know to suspect".  I don't think that is good engineering.  
Thats like saying you shouldnt worry amout something till something
terrible happens (He said catastropic).  To me this sucks.  If there
is even a slight cause for beleiving something may fail, it is good
engineering practice to look at a fix for it as quickly as possible.


>>>>very heavy, especially when filled with cargo.  Without much altitude
>>>>its hard to recover, actually it is a 1/billion chance.
>
>where does this probability data come from?  the 747 is certificated to
>continue climb following the failure of a single engine after V1.  what
>climb/descent rate can be expected after a double-asymmetric failure?
>what i am curious about is why there would be a controllability problem
>other than difficulty in maintaining altitude.  doesn't failure of both
>engines on one side result in a configuration analogous to single-engine
>failure on a twin jet (e.g. a 737, A300, 757 etc)?  clearly the loss of
>half the available power on a 747 is more serious than on a 737 because
>the 737 will climb after losing 50% of its power, while the 747 is only
>certificated to do so after loss of 25% of its power.  does anyone have
>some actual data to shed some light on this?  (note the sci. hierarchy).

No data.  Just an estimate by a 747 pilot.

>>More rambling?  You wanna try it?  Are you calling 747 pilots liars?
>>This is where my info is from.  What about any of yours?  All your cases
>>are unsubstantiated.
>
>ok derek, since this is a science group, and you are throwing around
>accusations such as the above, please go ahead and name just one of
>your 747 pilot sources.

I cant give a name ( I dont know it) but one of them was a US Carrier
pilot.  Ill look up the article and tell you what airline specifically,
and I will directly quote the article for your benefit.



Derek