As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD - FLT 1921 - EN ROUTE IAD-DFW - DETECTED RIGHT SIDE OIL PRESSURE DECREASE TO ZERO. RETURNED IAD AND LANDED WITHOUT FURTHER INCIDENT. REPLACED RIGHT SIDE ENGINE. ANALYSIS DETERMINED THAT THE OIL PRESSURE SENSING LINE FAILED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)