Oh, FFS.
The only reason the BA flight made the media was the FAA saw a chance to promote USA based airlines.
Parts of the FAA are required to promote USA Aviation.
Other parts deal with safety.
The safety part was extremely embarrassed by the political part going public about this issue.
pprune readers would not even know about that BA flight if the politicians in the FAA had not heard of the story.
As wiggy says, with a 4 engine plane, it is perfectly OK to run with 3 of them.
End of story.