To say the ILS outage was a contributory factor is nonsense.
In NTSB-speak, the absence of a glideslope, like pretty well any other aspect of the accident, is classed
at this stage simply as a "finding" - a fact or conclusion that may or may not have had a bearing on what happened.
By the time the investigation report is published, all findings will have been classified in one of 3 categories:
A. Probable Cause (of which there can, of course, be more than one)
B. Factor (a situation, circumstance or event that contributed to one or more of the causes)
C. Event (anything that isn't a Cause or Factor)
There is no specific sub-category for something that had a bearing on the accident, but really shouldn't have had ...