As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE THE DEICE TIMER LIGHT ILLUMINATED, THE CREW FOLLOWED THE QRH WHICH DIRECTED THEM TO LEAVE ICING CONDITIONS, DUE TO CURRENT WX THEY WERE NOT ABLE TO DEPART SO CREW DECLARED AN EMERGENCY AND RETURNED TO IAD. THE FLIGHT LANDED WITH OUT FURTHER INCIDENT. THE CABIN WAS PREPARED FOR AN EMERGENCY. REMOVED AND REPLACED REGULATOR VALVE RT SIDE IAW SAAB MM 36-11-05, REPAIRED LEAKING BOOT PATCH ON RT INBOARD BOOT IAW 30-10-35.