Back from Eternity (1956)
A surprisingly well made movie. The plot is a big contrivance in a way, a calculated drama of conflicting character types in a survival situation. But the acting is excellent, the script tight, and the direction and pacing really strong.
Robert Ryan leads the group, literally as the pilot of the doomed plane, and he's in great, restrained form. Eventually he is matched, as an actor, but the nuanced, quirky Rod Steiger, who plays a criminal of sorts. The two leading women are Anita Ekberg, who is here as an ornament as usual, but ends up being a decent character after all, and Phyllis Kirk, and dependable secondary actress.
It's probably coincidence, but here is a movie about an airplane by the studio (RKO) run by Howard Hughes, and aircraft industrialist. And it was one of RKO's last films, being ruined (along with all the studios) by the collapse of Old Hollywood. While not a big budget movie, the sets are contrived to work within their limitations, being stuck, as it were, in the jungle.
The weirdest thing here might be that the director (and producer), John Farrow, made the same movie in 1939. The first one is supposed to be better, but I haven't seen it, and this one holds its own. Partly it's just the searing acting of Steiger, and of Ryan. If the plot were not quite so improbable, and the inevitable weeding out of the survivors from the victims, the movie might be considered really excellent. It never wavers (except maybe the girl fight in the pool, which is stupidity), and it has lots of nuances and romantic touches.