In the scene where the last time one sees the priest praying, in the last 10-15 minutes of the film, the man behind the priest, in the far back of the left of the cabin, appears to be wearing a dark-colored German officer or NCO military cap and a field gray tunic with Wehrmacht lapel patches on it. He's kind of ducking down while the priest is in frame. In the following scenes, he is wearing a normal 1950s business suit.
At the first sign of engine trouble, the crew clearly looks out of their right-hand window, and at the rightmost engine. There are even a few brief shots of that engine flaming up, clearly on the right wing of the plane. However, just after that, all outside shots of the plane show the leftmost propeller has stopped and the rightmost propeller spinning normally.
Although not stated in the film, the filmmakers clearly intended to depict a Douglas DC-7C. In the exterior scenes we see the "7 Seas" logo on the vertical fin, and in the close-up scenes of the engines we see four-blade props and prop spinners, as on a DC-7. However, with the exception of the logo, the plane shown in the exterior scenes is a DC-4, evident by the more rounded shape of the vertical fin, the length of the aircraft and no prop spinners.
In the exterior shots, the airplane is actually a DC-6, The DC-7 had four-bladed props with spinners. As incorrectly mentioned above, the airplane is not a DC-4--the DC-4 had oval cabin windows.
The information above is incorrect. Both outboard engines have failed, the were able to feather the left (#1) engine which keeps the prop from rotating and creating drag. They failed at an attempt to feather the right (#4) engine so it continued to spin from the airflow which creates additional drag and thus needed extra fuel to make their destination. This is the reason they were forced to ditch.