B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 151; Flight Crew Total 4723; Flight Crew Type 4723
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
Upon completing the flight in ZZZ Tech Ops requested me to look at aircraft exterior problem. I met him and he showed the forward drain mast had failed and was detached from fuselage but still attached by the drain tube. A visual inspection showed that the trailing 75% of the fairing attach point had been fatigued and failed for some time. There was a fresh break in the forward 25% of the fairing attach point. All components looked intact; but dangling by the drain tube. I did the walk around in ZZZ1; and with total certainty the fairing was in place and attached. It did not appear that a ground object or bird had caused the damage. I believe it just structurally failed during the flight. Tech Ops said they had entered the discrepancy.
B737 Captain reported that a drain mast had fatigued and failed during flight and was discovered at the destination airport by maintenance.