B737-800
Flight Crew Air Transport Pilot (ATP)
Distraction; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Less Severe
Flight Crew Took Evasive Action; General Maintenance Action
Aircraft
This event occurred in cruise flight at FL360. While donning my oxygen mask in preparation for the First Officer to leave the cockpit; the inflated harness burst and failed. Exercising Captain's Emergency Authority; I removed the mask from its storage compartment and replaced it with the O2 mask from the First Observer's seat; as that seat was unoccupied. After ensuring proper operation of the mask and microphone; we resumed normal operations.
While donning his oxygen mask in preparation for First Officer's break; a B737-800 Captain's oxygen mask inflatable harness burst. An observer's mask replaced the Captain's for the flight's duration.