Navaids?
Any Conghonas aviators confirm approach aid details? Looks like NDB and VOR/DME but no ILS on any of the runways.
Might ILS have helped (assuming they had somewhere to put the localiser arrays)? The weather was dull and damp but scarcely on minimums, and presumably the PAPIs were working.
As usual the last thing we will learn is if there was an unexpected distraction or technical malfunction.