As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6205 - IAD-MHT - DURING CLIMB-OUT, RETURNED TO IAD DUE TO THE DUCT FAIL CAP LIGHT ILLUMINATING. AIRCRAFT LANDED AT IAD WITH NO FURTHER INCIDENTS. MX REPLACED THE RIGHT DUCT O-RINGS. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)