F-100 crash in Sao Paulo

From:         tassio@watson.ibm.com
Organization: IBM T.J. Watson Research Center
Date:         08 Nov 96 05:24:22 
Followups:    1 2
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   I have been following the news in Brazilian newspapers on the cause
of the TAM F-100 crash in Sao Paulo, Brazil.
  Two members of a maintenance crew at the airport witnessed the
inadvertent deployment of the thrust reverse in the right engine as
the airplane was about to get airborne.
   The maintenance records indicate uncommanded thrust reverse
deployment in flight for this very engine in the last few weeks. I don't
know which maintenance actions were taken as a result of this, but if
there were none, TAM will probably be found negligent. Of course, none
of this is official report yet.
   This particular airport has a short runway. If the deployment
had occurred prior to V1, the crew would have aborted the take-off.
If the deployment had occurred later in flight, I imagine the aircraft would
have enough speed to return to the airport.
   From what I know, power requirements for take-offs consider only an
engine *failure*, which translates to me as thrust = 0, but never this kind
of situation where an engine might actually be contributing with negative
thrust. Am I correct?