I am from Madagascar and I believe my father had a french passport. He
was in the French militry for 15 years and traveled back and forth
from France to Madagascar. How can I trace my Fathers passport details
as he is now dead and his records were distroyed in a flood. I want to
try and get French citizenship through my fathers French passport.

I'm sorry to give you bad news, but it seems to be impossible for you
to apply for French nationality after your father's death.

" . .  vous devez résider avec votre père ou votre mère devenu/e français/e. "
http://www.justice.gouv.fr/publicat/gnationab.htm#2

If you would like to double-check this, you could ask at the French
consulate in Madagascar:
http://www.madagascar-contacts.com/consulfrance-tananarive/