Here's a leaking oil issue many of you probably don't know about.

I used to wrench on jets for my Uncle Sugar and his Yacht Club (U.S. Navy).
Pilots and aircrew do walk-around inspections of any aircraft they were to fly that day. F-14 pilots would check for hydraulic leaks on the flight line. No leaks, it must be empty and they would often refuse to accept the aircraft.

Interestingly enough, at altitude and speed, the fittings don't leak. Sitting on the line, they almost poured. In my early days, I got very good at working the handle on a HSU (hydraulic servicing unit).