Allegheny lost a pair of CV-580s at BFD less than two weeks apart (
24 Dec 1968 and
6 Jan 1969) ... both flights were making approaches in blowing snow and low-visibility conditions; approximately half the passengers survived each accident
a significant outcome of the investigations was that AL revised their company procedures for approaches at airports without an Instrument Landing System to require minimum visibility of 1000 feet vertical and three miles horizontal