As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PARABOLA NUMBER 2 STRONG SMELL IN FLIGHT DECK AND CABIN AFTER NUMBER 5. COULD NOT IDENTIFY AND RETURNED TO BASE. MAINTENANCE FOUND THE SMELL TO BE SKYDROL FROM THE HYDRAULIC RESERVOIR PRESSURE REGULATOR LEAKING INTO THE PRESSURIZING LINE. THE LINES WERE FLUSHED AND THE REGULATOR WAS REPLACED.