Re: F-100 crash in Sao Paulo

Date:         10 Nov 96 05:29:12 
From:         Stephan Stephany <stephan@lac.inpe.br>
Organization: INPE
References:   1
Followups:    1 2
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tassio@watson.ibm.com wrote:
>
>    This particular airport has a short runway.

Not so short. Congonhas airport (SAO) has two runways (lengths
1,939 and 1,437 meters, don't know which was used by the ill-fated
F-100). The destination airport in Rio de Janeiro city was the
Santos Dumont airpot (SDU), also with 2 runways (1,323 and 1,260
meters, that is both with less than 1 stat mile) and there's a lot
of mountains, etc. around (not the case in SAO).

> 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?

Surely, as a twin engine aircraft it should have the capability to
take-off using only one engine, but with the other shut down and
not "braking" the aircraft. Reportedly, the plane took off and
the right thrust reverser opened and closed *four* times (during
the take-off run and the 100 ft climb).

In addition, *according* to the Brazilian press: after the examination
of the DFDR and CVR at the manufacturer (Allied Signal?) in USA, the
investigation board think that the crew was unaware of the thrust
reverser deployment. Each time the reverser was deployed, due to a
failure in the hydraulic shut off valve of the reverser or due to a
failure in the relay that commands that valve (who knows?), the throtle
came back to idle and the crew push it back to full power - the crew
thought it was a problem with the autotrotle, according to some
incidents with the autothrotle that happened before. Any mesage like
"reverser not locked" was inhibit during take-off. As I said in a
former msg, the crew was had a lot of experience (PIC had 12,000 hs
flight, 10,000 of these flying TAM) and also the 1st officer had some
thousand hours, but it seems they had not any chance.

Nobody knows if it was a faulty maintenance or a defective spare part
or even a design error. The investigation board went to Fokker and
probably they will reproduce the flight in a F-100 simulator (maybe
they already did it). It seems that Fokker is going to recommend
specific training for that situation, maybe a recall (if it is the
case of faulty spares) and maybe some s/w modificationto warn about
thrust reverser deployment during take-off on the EFIS.

Well, still they have to find out what caused the deployment of the
reverser.

Stephan Stephany
National Institute for Space Research
S. Jose dos Campos - BRAZIL