Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!att!cbnews!military
From: ricko@rosevax.Rosemount.COM (Rick O'Brien)
Newsgroups: sci.military
Subject: Re: F-4 : really an interceptor
Summary: Question on cause of aircraft losses
Keywords: Light Off Detection
Message-ID: <7877@cbnews.ATT.COM>
Date: 30 Jun 89 03:19:45 GMT
References: <7740@cbnews.ATT.COM> <7832@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: Rosemount Inc., Eden Prairie, MN
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Approved: military@att.att.com



From: ricko@rosevax.Rosemount.COM (Rick O'Brien)

[Lots of interesting stuff deleted]

>              In 1972 the NAVY projected that for every 1000 flight hours,
>the engines in the Tomcat would see 597 afterburner lights and 1165 engine
>cycles (1 cycle being running engine through all power settings).  Between
>January 1975 and November 1978, we lost 31 Tomcats, with 35% (11) being
>lost due to the TF30 (~$400 M worth of planes).  
>
[More editing]
Does anyone have any info on what were the specific engine problems that
caused the loss of the aircraft?  I have heard rumors (from our marketing
types talking to people who don't actually work with the engines) that
on occasion when going to augmentor that one or the other burner may not
light and the LOD's (Light Off Detectors) doesn't pick up the lack of
ignition in time to let the engine controller know to shut down the 
increased fuel flow.  I understand that this situation is very uncomfortable
for the pilot & NFO.  I am working on a new design for LOD's (current 
technology uses a Gieger-Mueller tube to count UV photons) and would 
appreciate any solid information on this topic.  It seems that getting
something other than rumors on  in service engine sensors it extremely
difficult (many times the people using the sensors don't understand the
technology of the sensor; all they know is that it works or it doesn't.)

Thanks in advance.

Rick O'Brien

>------------------------------------------------------------------------------
>Fred J. Shubert         | "You haven't lived until you've seen a 'cat fly!!!"
>AT&T Bell Labs          |-----------------------------------------------------
>Whippany, N.J.          | DISCLAIMER:  All views are that of my own. PERIOD.
>Ma-Bell 201-386-3094    |