B767 first officer reported diverting to an alternate airport after flight attendants and passengers...

Narrative:

While in cruise at FL380 the flight attendants called to let us know there was an unusual smell that several passengers had alerted them to that we quickly smelled. It did not last long and while looking at the overhead panel I noticed the gasper fans showed off with no EICAS or status message. The captain and I checked the QRH and found no checklist. The flight attendants called and said the smell was quickly dissipating. We felt this was something that overheated and had shut itself off. The other first officer who was on break was awakened and asked to check the cabin for any signs of smoke. While he was looking we attempted to use satcom to call dispatch and get patched through to [maintenance] which took almost 15 minutes to accomplish. The other first officer who was to be the flying pilot for landing called back and said the smell had returned and several passengers were complaining about it. By now we were talking with dispatch and [maintenance] as well as each other and all three of us decided since the smell returned no need for further risk and we diverted to [a nearby alternate]. Before we descended the other first officer switched seats with me and I resumed the position of relief officer. We landed uneventfully and taxied to the gate.

Original NASA ASRS Text

Title: B767 First Officer reported diverting to an alternate airport after flight attendants and passengers noticed an unusual smell in the cabin that may have been associated with the gasper fans.

Narrative: While in cruise at FL380 the flight attendants called to let us know there was an unusual smell that several passengers had alerted them to that we quickly smelled. It did not last long and while looking at the overhead panel I noticed the gasper fans showed off with no EICAS or status message. The Captain and I checked the QRH and found no checklist. The flight attendants called and said the smell was quickly dissipating. We felt this was something that overheated and had shut itself off. The other First Officer who was on break was awakened and asked to check the cabin for any signs of smoke. While he was looking we attempted to use SATCOM to call Dispatch and get patched through to [Maintenance] which took almost 15 minutes to accomplish. The other First Officer who was to be the flying pilot for landing called back and said the smell had returned and several passengers were complaining about it. By now we were talking with Dispatch and [Maintenance] as well as each other and all three of us decided since the smell returned no need for further risk and we diverted to [a nearby alternate]. Before we descended the other First Officer switched seats with me and I resumed the position of relief officer. We landed uneventfully and taxied to the gate.

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.

Attributes
ACN	1354480
Time
Date	201605
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B767 Undifferentiated or Other Model
Flight Phase	Cruise
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Type 1210
Events
Anomaly	Aircraft Equipment Problem Less Severe Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

B767 first officer reported diverting to an alternate airport after flight attendants and passengers noticed an unusual smell in the cabin that may have been associated with the gasper fans.