Narrative:

We departed from ZZZ uneventfully enroute to ZZZ1. I was sitting third seat and the captain was the pilot flying. As previously agreed; myself and the first officer in the fourth seat would take first break; so we went to the bunks after top of climb. About 4 hours into our break; I was awakened by a cockpit interphone call from the flight deck. Upon leaving the bunk; I observed the captain lying on the floor of the upper deck in an unresponsive state; being attended to by some of the 4 deadheading crewmembers. The remaining deadheading crew were in the flight deck assisting the operating first officer with the medical emergency. I inquired as to what was happening and was told that the captain was in his seat in casual conversation when he became unresponsive and was removed from his seat and attended to by the other deadheading crewmembers. I quickly informed the other operating first officer ( who was also summoned from the other bunk) of the situation. I quickly got dressed and took station in the third seat relieving the deadheading crewmembers of their communication and coordination with company; ATC; and medlink. The other relief first officer occupied the captain's seat. The crew was already diverting to the nearest suitable airport; ZZZZ; but based on the captain's partial recovery; both dispatch and medlink recommended proceeding to ZZZ2 so we agreed and changed diversion airport to ZZZ2. Procedures were then carried out to proceed to ZZZ2 followed by an uneventful landing at ZZZ2.

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Original NASA ASRS Text

Title: B747 flight crew reported that the Captain became unresponsive; causing the crew to divert.

Narrative: We departed from ZZZ uneventfully enroute to ZZZ1. I was sitting third seat and the Captain was the Pilot Flying. As previously agreed; myself and the First Officer in the fourth seat would take first break; so we went to the bunks after top of climb. About 4 hours into our break; I was awakened by a cockpit interphone call from the Flight Deck. Upon leaving the bunk; I observed the Captain lying on the floor of the upper deck in an unresponsive state; being attended to by some of the 4 deadheading crewmembers. The remaining deadheading crew were in the flight deck assisting the operating First Officer with the medical emergency. I inquired as to what was happening and was told that the Captain was in his seat in casual conversation when he became unresponsive and was removed from his seat and attended to by the other deadheading crewmembers. I quickly informed the other operating First Officer ( who was also summoned from the other bunk) of the situation. I quickly got dressed and took station in the third seat relieving the deadheading crewmembers of their communication and coordination with company; ATC; and Medlink. The other Relief First Officer occupied the Captain's seat. The crew was already diverting to the nearest suitable airport; ZZZZ; but based on the Captain's partial recovery; both Dispatch and Medlink recommended proceeding to ZZZ2 so we agreed and changed diversion airport to ZZZ2. Procedures were then carried out to proceed to ZZZ2 followed by an uneventful landing at ZZZ2.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.