fuel dump
From Wikpedia...
"United Airlines Flight 173 was a scheduled flight from John F. ... On December 28, 1978, the aircraft flying this route ran out of fuel while troubleshooting a landing gear problem and crashed in a suburban Portland neighborhood near NE 157th Avenue and East Burnside Street killing 10 people."
I believe that this was a DC8. It was dumping fuel and ran out on the way back to PDX