As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TUS - CREW REPORTED RT OIL PRESSURE DROPPED TO 40 PSI AFTER TAKEOFF. THEY PERFORMED AN AIR TURN BACK AND MADE AN UNEVENTFUL LANDING. MAINTENANCE INSPECTED AIRCRAFT AND MADE GROUND RUN, BUT COULD NOT DUPLICATE OIL PRESSURE FLUCTUATION. (X)