Name of this black and white movie?

a plane crashes in the jungle. among the pengers are and elderly couple a convict and a little girl. the find out the hard way that the natives are either headhunters or cannibals, they have to empty out the plane to make it lighter. they leave the convict and the elderly couple and the a gun with 2 bullets. the convict shoots the elderly couple to save them from the natives but does not have a bullet to same himself.