As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
# 1 engine low oil pressure light on in flight. Oil pressure was 46 psi. Engine was shut down at 0905 Z. Windmilling oil pressure on secured engine was 12 psi for 19 minutes. Replaced low pressure switch IAW DC-8 MM 79-30. Ran # 1 engine, no leaks noted. Engine indication normal. Replaced # 1 engine main oil filter, leak checked good.